8.0 Multiple Choice Questions (MCQs) I

Question 1

Viruses that cause zoonotic infections:<div>A. have non-humans as natural hosts</div><div>B. cause diseases with high mortality/morbidity</div><div>C. include influenza virus</div><div>D. may be transmitted by insects</div><div>E. include measles virus</div>

Answer 1

<div>Viruses that cause zoonotic infections:<div>A. have non-humans as natural hosts (TRUE)</div><div>B. cause diseases with high mortality/morbidity (TRUE)</div><div>C. include influenza virus (TRUE)</div><div>D. may be transmitted by insects (TRUE)</div><div>E. include measles virus (FALSE)</div></div>

Question 2

The group of reversiviruses includes<div>A. human immunodeficiency virus</div><div>B. variola virus</div><div>C. hepatitis C virus</div><div>D. Rous sarcoma virus</div><div>E. hepatitis B virus</div>

Answer 2

<div>The group of reversiviruses includes<div>A. human immunodeficiency virus (TRUE)</div><div>B. variola virus (FALSE)</div><div>C. hepatitis C virus (FALSE)</div><div>D. Rous sarcoma virus (TRUE)</div><div>E. hepatitis B virus (TRUE)</div></div>

<div><br></br></div>

<div>Reversiviruses replicate their genome via a reverse transcriptase step - and shares this property with retroviruses.</div>

<div><br></br></div>

<div>B - F; variola virus is a poxvirus e.g. smallpox</div>

<div>C - F; a flavivirus</div>

Question 3

These viruses commonly enter their host via the alimentary canal<div>A. Rotavirus</div><div>B. Blue tongue virus</div><div>C. Hepatitis B virus</div><div>D. Rhinovirus</div><div>E. Poliovirus</div>

Answer 3

<div>These viruses commonly enter their host via the alimentary canal<div>A. Rotavirus (TRUE)</div><div>B. Blue tongue virus (FALSE)</div><div>C. Hepatitis B virus (FALSE)</div><div>D. Rhinovirus (FALSE)</div><div>E. Poliovirus (TRUE)</div></div>

<div><br></br></div>

<div>B - F; transmitted by blood biting insects</div>

<div>C - F; transmitted via blood e.g. iatrogenic</div>

<div>D - F; transmitted via the respiratory tract e.g. common cold</div>

<div>Viruses that commonly enter via the alimentary canal include poliovirus, hepatitis A virus, rotavirus, enteric adenoviruses</div>

Question 4

Interferon beta<div>A. Is induced following activation of Toll-like receptors</div><div>B. Induces expression of interferon stimulated genes (ISGs) via NFkB</div><div>C. Signals through type 1 IFN receptors</div><div>D. Directly binds viruses and blocks entry</div><div>E. Up-regulates class I MHC</div>

Answer 4

<div>Interferon beta<div>A. Is induced following activation of Toll-like receptors (TRUE)</div><div>B. Induces expression of interferon stimulated genes (ISGs) via NFkB (FALSE)</div><div>C. Signals through type 1 IFN receptors (TRUE)</div><div>D. Directly binds viruses and blocks entry (TRUE)</div><div>E. Up-regulates class I MHC (FALSE)</div></div>

<div><br></br></div>

<div><br></br></div>

<div>B - F; NFkB leads to the production of IFN alpha/beta which then goes on to stimulate ISGs through JAK-STAT pathway and ISGF-3</div>

<div>D - F; they induce downstream pathways that leads to increased likelihood of recognition by the immune system (MHC-class I indirectly upregulated) and they inhibit viral protein synthesis via production of OAS, Mx, PKR</div>

Question 5

Yellow Fever Virus<div>A. Is a zoonotic infection</div><div>B. Is commonly transmitted congenitally</div><div>C. Causes respiratory infection</div><div>D. Is a non-enveloped RNA virus</div><div>E. Causes haemorragic fever</div>

Answer 5

<div>Yellow Fever Virus<div>A. Is a zoonotic infection (TRUE)</div><div>B. Is commonly transmitted congenitally (FALSE)</div><div>C. Causes respiratory infection (FALSE)</div><div>D. Is a non-enveloped RNA virus (FALSE)</div><div>E. Causes haemorragic fever (TRUE)</div></div>

<div><br></br></div>

<div>B - F; it is transmitted by the female aedes aegypti mosquito</div>

<div>C - F; causes haemorrhagic fever<br></br>D - F; is a flavivirus which are enveloped viruses; they are positive strand ssRNA viruses</div>

Question 6

Influenza Virus<div>A. Is an RNA virus</div><div>B. Encodes an ion channel protein that promotes un-coating of the virus</div><div>C. Causes disease with high seasonality in temperate climates</div><div>D. Requires a high pH environment to activate membrane fusion</div><div>E. Pandemics are associated with HA drift</div>

Answer 6

<div>Influenza Virus<div>A. Is an RNA virus (TRUE)</div><div>B. Encodes an ion channel protein that promotes un-coating of the virus (TRUE)</div><div>C. Causes disease with high seasonality in temperate climates (TRUE)</div><div>D. Requires a high pH environment to activate membrane fusion (FALSE)</div><div>E. Pandemics are associated with HA drift (FALSE)</div></div>

<br></br><div>D - F; it requires a low pH. Low pH leads to a conformational change in the HA2 subunit that allows the fusion peptide (N terminal part) to integrate into the endosomal membrane. This destabilises the membrane and promotes fusion between the viral envelope and the endosomal membrane.</div><div>E - F; pandemics are associated with HA shift; shifts results in production of new strains due to reassortment of RNA segments between two virions of different strains within a cell infected by them both at the same time</div>

Question 7

Pattern-recognition receptors (PRRs)<div>A. Are important for viral entry</div><div>B. Mediated phagocytosis of free virus particles</div><div>C. PRRs activate the JAK-STAT signalling pathway within the infected cell</div><div>D. Detect viral DNA in the cytoplasm</div><div>E. Activate the IRF3 TF within the infected cell</div>

Answer 7

<div>Pattern-recognition receptors (PRRs)<div>A. Are important for viral entry (FALSE)</div><div>B. Mediated phagocytosis of free virus particles (TRUE)</div><div>C. PRRs activate the JAK-STAT signalling pathway within the infected cell (FALSE)</div><div>D. Detect viral DNA in the cytoplasm (TRUE)</div><div>E. Activate the IRF3 TF within the infected cell (TRUE)</div></div>

<div><br></br></div>

A - F; PRRs are important host cell viral recognition proteins that detect PAMPS such as nucleic acids in the cytoplasm, and they activate the innate immune system.<div>C - F; the JAK-STAT pathway is activated in neighbouring cells, that helps to protect them from viral infection</div>

Question 8

Human immunodeficiency virus (HIV)<div>A. Binds to macrophages using the CCR5 cytokine receptor</div><div>B. Is a zoonotic infection</div><div>C. Converts its positive sense RNA genome into DNA via reverse transcription</div><div>D. Is controlled by CD8+ cytotoxic T lymphocytes in patients termed ‘slow progressors’</div><div>E. Requires ribosomal frame-shifting to express env</div>

Answer 8

<div>Human immunodeficiency virus (HIV)<div>A. Binds to macrophages using the CCR5 cytokine receptor (TRUE)</div><div>B. Is a zoonotic infection (TRUE)</div><div>C. Converts its positive sense RNA genome into DNA via reverse transcription (TRUE)</div><div>D. Is controlled by CD8+ cytotoxic T lymphocytes in patients termed 'slow progressors' (TRUE)</div><div>E. Requires ribosomal frame-shifting to express env (FALSE)</div></div>

<div><br></br></div>

<div>E - F; expression of env protein requires splicing, expression of gag vs. gag-pol requires frame-shifting</div>

Question 9

In viral infection:<div>A. Herpes virus establish persistent (latent) infections</div><div>B. Hepatitis B establishes persistent (chronic) infection in about 90% of normal adults</div><div>C. Measles virus always causes an acute infection</div><div>D. Varicella zoster virus establishes latency in sensory ganglia</div><div>E. Influenza viruses always cause acute infection</div>

Answer 9

<div>In viral infection:<div>A. Herpes virus establish persistent (latent) infections (TRUE)</div><div>B. Hepatitis B establishes persistent (chronic) infection in about 90% of normal adults (FALSE)</div><div>C. Measles virus always causes an acute infection (FALSE)</div><div>D. Varicella zoster virus establishes latency in sensory ganglia (TRUE)</div><div>E. Influenza viruses always cause acute infection (TRUE)</div></div>

<div><br></br></div>

A - they establish latent infection in sensory nerves<div>B - it establishes chronic infection in about 90% of neonates but the rates are much lower in adults [~10%]</div><div>C - if people are vaccinated they won’t necessarily get the acute infection + measles virus mutants can persist in the CNS and cause a chronic demyelinating disease (SSPE) with a frequency of about 1/million infections</div><div>D - hence classic dermatomal pattern of reactivation</div><div>E - T</div>

Question 10

The following statements are true:<div>A. Cryptococcus neoformans causes a slowly progressive meningo-encephalitis</div><div>B. Invasive infections with Aspergillus fumigatus has high fatality</div><div>C. Candida albicans is a common commensal organism of human mucous membranes</div><div>D. Structural barriers play a minor role in innate protections from fungal infection</div><div>E. Protein synthesis in fungi can be blocked by nystatin</div>

Answer 10

<div>The following statements are true:<div>A. Cryptococcus neoformans causes a slowly progressive meningo-encephalitis (TRUE)</div><div>B. Invasive infections with Aspergillus fumigatus has high fatality (TRUE)</div><div>C. Candida albicans is a common commensal organism of human mucous membranes (TRUE)</div><div>D. Structural barriers play a minor role in innate protections from fungal infection (FALSE)</div><div>E. Protein synthesis in fungi can be blocked by nystatin (FALSE)</div></div>

<div><br></br></div>

A; T - abundant in bird droppings and possesses a thick polysaccharide capsule that is an important virulence determinant. Infection is acquired by inhalation. The organism has a strong tendency to spread from the lungs through the circulation to the CNS. In people who are HIV positive, or immunosuppressed it can cause a slowly worsening meningo-encephalitis, with progessively worsening headache, fever, confusion, hydrocephalus (insufficient reabsorption of CSF), and then coma. 20% fatality; survivors often have persistent neurological disability including blindness. Can treat with amphotericin plus flucytosine, followed by long-term high-dose fluconazole.<div>B; T - an environmental mould that occurs worldwide and produces abundant air-borne spores which are inhaled by people every day (hospital re-building work, mouldy hay, compost heaps), causes airway colonisation, aspergilloma and invasive infection of lung or paranasal sinuses and spreads along blood vessels leading to dissemintated infection. Invasive infection has a very high fatatlity. Treatment is with amphotericin or voriconazole, and surgery if possible.<br></br>C; T - moist epithelial surfaces, usually restrained by host defences and bacterial competition<br></br>D; F - the intact epithelium of the skin or moist mucosal surfaces of the mouth, intestine, genital tract are key structural barriers to prevent fungal entry. Damage to it can lead to fungal invasion, through the epithelium, into the connective tissue and blood vessels followed by dissemiantion to other parts of the body.<br></br>E; F - nystatin blocks ergosterol function in fungal membranes.</div>

Question 11

Regarding fungal infection:<div>A. Ringworm is a superficial fungal infection</div><div>B. The candidate albicans toxin candidalysin targets endothelial cells</div><div>C. Cryptococcus neoformans is abundant in bird-droppings</div><div>D. Aspergillus fumigatus is a filamentous saprophyte</div><div>E. Filamentous fungi are common components of the normal human flora</div>

Answer 11

<div>Regarding fungal infection:<div>A. Ringworm is a superficial fungal infection (TRUE)</div><div>B. The candidate albicans toxin candidalysin targets endothelial cells (FALSE)</div><div>C. Cryptococcus neoformans is abundant in bird-droppings (TRUE)</div><div>D. Aspergillus fumigatus is a filamentous saprophyte (TRUE)</div><div>E. Filamentous fungi are common components of the normal human flora (FALSE)</div></div>

Question 12

Regarding Fungi<div>A. Most are saprophytes</div><div>B. Many are parasites of humans and animals</div><div>C. They can be eukaryotes or prokaryotes</div><div>D. They have a cell wall containing both chitin and glucans</div><div>E. Many, but not all, are dimorphic</div>

Answer 12

<div>Regarding Fungi<div>A. Most are saprophytes (TRUE)</div><div>B. Many are parasites of humans and animals (FALSE)</div><div>C. They can be eukaryotes or prokaryotes (FALSE)</div><div>D. They have a cell wall containing both chitin and glucans (TRUE)</div><div>E. Many, but not all, are dimorphic (TRUE)</div></div>

Question 13

In fungi<div>A. DNA is organised in chromosomes within a membrane-bound nucleus</div><div>B. Hyphae are branching cylinders that grow by cell division</div><div>C. At 37 degrees the spores of dimorphic fungi germinate into yeasts</div><div>D. The azole toxin drug Fluonazole inhibits the synthesis of fungal microtubules</div><div>E. The anti-fungal drug Caspofungin inhibits the synthesis of glucan, a component of the cell wall</div>

Answer 13

<div>In fungi<div>A. DNA is organised in chromosomes within a membrane-bound nucleus (TRUE)</div><div>B. Hyphae are branching cylinders that grow by cell division (TRUE)</div><div>C. At 37 degrees the spores of dimorphic fungi germinate into yeasts (TRUE)</div><div>D. The azole toxin drug Fluonazole inhibits the synthesis of fungal microtubules (FALSE)</div><div>E. The anti-fungal drug Caspofungin inhibits the synthesis of glucan, a component of the cell wall (TRUE)</div></div>

<div><br></br></div>

<br></br>D - F; fluconazole is an azole class but it inhibits synthesis of ergosterol which is part of the cell membrane. Ergotamine is a toxin produced by fungi.<br></br>

Question 14

In haematopoiesis<div>A. NK cells derive from the common lymphoid precursor</div><div>B. Platelets are derived from erythroblasts</div><div>C. Macrophages and dendritic cells are both derived from monocytes</div><div>D. Plasma cells give rise to B cells</div><div>E. The common myeloid progenitor gives rise to both granulocytes and monocytes</div>

Answer 14

<div>In haematopoiesis<div>A. NK cells derive from the common lymphoid precursor (TRUE)</div><div>B. Platelets are derived from erythroblasts (FALSE)</div><div>C. Macrophages and dendritic cells are both derived from monocytes (TRUE)</div><div>D. Plasma cells give rise to B cells (FALSE)</div><div>E. The common myeloid progenitor gives rise to both granulocytes and monocytes (TRUE)</div></div>

Question 15

The cell surface molecule<div>A. LFA-1 is a marker for T cells</div><div>B. CD8 binds to MHC class II molecules</div><div>C. ICAM-1 binds to LFA1</div><div>D. CD4 is expressed on helper T cells</div><div>E. CD3 is expressed on the majority of NK cells</div>

Answer 15

<div>The cell surface molecule<div>A. LFA-1 is a marker for T cells (FALSE)</div><div>B. CD8 binds to MHC class II molecules (FALSE)</div><div>C. ICAM-1 binds to LFA1 (TRUE)</div><div>D. CD4 is expressed on helper T cells (TRUE)</div><div>E. CD3 is expressed on the majority of NK cells (FALSE)</div></div>

<div><br></br></div>

A - F; LFA-1 is a marker for neutrophils. They are integrin family adhesion molecules that bind to Ig superfamily molecules, ICAMs. They mediate tight binding. Initially the interactions are weak but signalling through chemokine receptors causes a conformationl changes in LFA-1 that reuslts in a high affinity binding state.<div>B - F; CD8 binds to MHC class I molecules.</div><div>E - F; FCgammaRIII is involved; it recognises antigen/antibody complexes. Ligation of this receptor leads to release of cytoplasmic granules containing lytic enzymes. This leads to ADCC.</div>

Question 16

Pattern recognition receptors include:<div>A. TLR5 which binds flagellin</div><div>B. TLR3 which in conjunction with CD14 recognises LPS</div><div>C. NOD2 which recognises muramyl dipeptide</div><div>D. TLR9 which binds methylated CpG-rich DNA</div><div>E. NLRP3 (also known as NALP3) which recognises cholesterol crystals</div>

Answer 16

<div>Pattern recognition receptors include:<div>A. TLR5 which binds flagellin (TRUE)</div><div>B. TLR3 which in conjunction with CD14 recognises LPS (FALSE)</div><div>C. NOD2 which recognises muramyl dipeptide (TRUE)</div><div>D. TLR9 which binds methylated CpG-rich DNA (FALSE)</div><div>E. NLRP3 (also known as NALP3) which recognises cholesterol crystals (TRUE)</div></div>

<br></br>B - F; TLR3 recognises double-stranded viral RNA and it forms a homodimer. LPS is recognised by TLR4 homodimer.<br></br>D - F; TLR9 recognises unmethylated CpG-rich DNA because methylated is eukaryotic.

Question 17

In the acute inflammatory response:<div>A. Histamine comes from stored sources</div><div>B. Leukotrienes are actively synthesised</div><div>C. C3a, C3b, C5a are derived from precursors present in plasma</div><div>D. Mast cells release endogenous pyrogens to activate the acute phase response</div><div>E. Histamine is released from mast cells by substance P released from nerve fibres</div>

Answer 17

“<div>In the acute inflammatory response:<div>A. Histamine comes from stored sources (TRUE)</div><div>B. Leukotrienes are actively synthesised (TRUE)</div><div>C. C3a, C3b, C5a are derived from precursors present in plasma (TRUE)</div><div>D. Mast cells release endogenous pyrogens to activate the acute phase response (FALSE)</div><div>E. Histamine is released from mast cells by substance P released from nerve fibres (TRUE)</div></div><div><br></br></div><br></br>D - F; macrophages release endogenous pyrogens [e.g. molecules/cytokines that induce fever]. These include IL-1beta, TNF-alpha and IL-6.”

Question 18

In the complement system:<div>A. The classical pathway is always first to act</div><div>B. The alternative pathway is the main pathway responsible for generating C3b</div><div>C. Factor H speeds up activation of the alternative pathway</div><div>D. DAF disrupts the C3 convertase C3bBb</div><div>E. MCP makes C3b susceptible to cleavage by factor I</div>

Answer 18

“<div>In the complement system:<div>A. The classical pathway is always first to act (FALSE)</div><div>B. The alternative pathway is the main pathway responsible for generating C3b (TRUE)</div><div>C. Factor H speeds up activation of the alternative pathway (FALSE)</div><div>D. DAF disrupts the C3 convertase C3bBb (TRUE)</div><div>E. MCP makes C3b susceptible to cleavage by factor I (TRUE)</div></div><div><br></br></div>A - F; the first to act is the alternative pathway, then the lectin pathway and then finally the classical pathway<div>C - F; factor H antagonises the alternative pathway. It is the main control factor responsible for regulating complement activation in solution. It is a soluble cofactor for factor I that attaches to sialic acid on host membranes. It causes dissociation of C3bBb (the alternative pathway C3 convertase) and makes C3b susceptible to cleavage by factor I.</div>”

Question 19

The following statements regarding cytokines are true:<div>A. IL-12 activates NK cells.</div><div>B. IL-4 inhibits the generation of Th1 cells</div><div>C. IL-8/CXCL8 is referred to as an endogenous pyrogen</div><div>D. Neutrophils follow a concentration gradient of IL-8/CXCL8</div><div>E. IL-6 activates the acute phase response</div>

Answer 19

“<div>The following statements regarding cytokines are true:<div>A. IL-12 activates NK cells. (TRUE)</div><div>B. IL-4 inhibits the generation of Th1 cells (TRUE)</div><div>C. IL-8/CXCL8 is referred to as an endogenous pyrogen (FALSE)</div><div>D. Neutrophils follow a concentration gradient of IL-8/CXCL8 (TRUE)</div><div>E. IL-6 activates the acute phase response (TRUE)</div></div><div><br></br></div><br></br>C - F; CXCL8 activates and recruits NK cells, as well as neutrophils. It is a chemokine e.g. controlled in cell movement.”

Question 20

In the complement system:<div>A. The membrane attack complex is initiated by cleavage of factor C5.</div><div>B. C3b and C5b increase inflammation and enhance vascular permeability.</div><div>C. Mannose-binding lectin interacts with MASP-1 and MASP-2.</div><div>D. The alternative pathway C3 convertase is C4bC2a.</div><div>E. C-reactive protein on bacterial surfaces recruits complement component C2.</div>

Answer 20

“<div>In the complement system:<div>A. The membrane attack complex is initiated by cleavage of factor C5. (TRUE)</div><div>B. C3b and C5b increase inflammation and enhance vascular permeability. (FALSE)</div><div>C. Mannose-binding lectin interacts with MASP-1 and MASP-2. (TRUE)</div><div>D. The alternative pathway C3 convertase is C4bC2a. (FALSE)</div><div>E. C-reactive protein on bacterial surfaces recruits complement component C2. (FALSE)</div></div><div><br></br></div><div>B - F; C3a and C5a are anaphylatoxins which stimulate inflammation; not the b parts<br></br>D - F; the classical C3 convertase is the C3bC2a. The alternative pathway C3 convertase is C3bBb<br></br>E - F; CRP on bacterial surfaces recruits complement component leads to activation of the classical pathway. Cq1 can bind to CRP, and this leads to activation of C1r and C1s subunits. C1s is able to cleave C4 to expose a reactive thioester group which can covalently attach C4b to the pathogen surface. Activated C1 then associates with and cleaves C2 depositing the C2a fragment on C4b forming C4bC2a, the classical C3 convertase. This can cleave C3 and deposit C3b on the microbial surface, and then membrane associated C3b generated can utilise the alternative pathway amplification loop by binding to factor B to generate C3bBb. The classical convertase C3bC2a can also associate with C3b to generate C4bC2aC3b, a classical pathway C5 convertase.</div>”

Question 21

Immunological tolerance:<div>A. Can involve regulatory T cells which have the signature transcription factor GATA3.</div><div>B. In pregnancy involves IDO which catabolises tryptophan.</div><div>C. Depends on the transcription factor IPEX being expressed in the thymus</div><div>D. Requires that all B cells with receptors that recognise self undergo apoptosis or anergy</div><div>E. Can be induced if T-cells receive signalling through MHC 1 in the absence of costimulation</div>

Answer 21

“<div>Immunological tolerance:<div>A. Can involve regulatory T cells which have the signature transcription factor GATA3. (FALSE)</div><div>B. In pregnancy involves IDO which catabolises tryptophan. (TRUE)</div><div>C. Depends on the transcription factor IPEX being expressed in the thymus (FALSE)</div><div>D. Requires that all B cells with receptors that recognise self undergo apoptosis or anergy (FALSE)</div><div>E. Can be induced if T-cells receive signalling through MHC 1 in the absence of costimulation (TRUE)</div></div><div><br></br></div>A - F; T regs are positive for FOXP2. GATA3 transcription factor is the signature Th2 TF.<br></br>C - F; Depends on the TF AIRE in the thymus. IPEX is an X-linked disease that only occurs in boys in which there is a lack of Tregs due to mutations in FOXP3; they die by two years unless treated due to lymphoproliferation and autoimmunity because of a lack of self-tolerance<br></br>D - F; because they require T cell activation if the T cell is tolerised then the B cell is not a worry”

Question 22

Regarding autoimmunity:<div>A. C1, C2 or C4 complement deficiency predisposes to SLE</div><div>B. Type 1 diabetes is more prevalent in individuals with an aspartate residue in position 57 in DQB1</div><div>C. EAE (experimental autoimmune encephalomyelitis) is predominantly due to T_H2 T cells</div><div>D. Myasthenia gravis involves antibodies to TSH recepetor</div><div>E. T_FH (T-follicular helper) cells principally activate macrophages</div>

Answer 22

“<div>Regarding autoimmunity:<div>A. C1, C2 or C4 complement deficiency predisposes to SLE (TRUE)</div><div>B. Type 1 diabetes is more prevalent in individuals with an aspartate residue in position 57 in DQB1 (FALSE)</div><div>C. EAE (experimental autoimmune encephalomyelitis) is predominantly due to T_H2 T cells (FALSE)</div><div>D. Myasthenia gravis involves antibodies to TSH recepetor (FALSE)</div><div>E. T_FH (T-follicular helper) cells principally activate macrophages (FALSE)</div></div><div><br></br></div><br></br>B - F; less prevalent with the charged aspartate<br></br>C - F; predominantly due to CD4+ T helper cells, but not specific to Th2 cells<br></br>D - F; Grave’s disease<br></br>E - F; they principally activate B cells; they are responsible for antibody development, isotope switching and affinity maturation”

Question 23

In transplantation:<div>A. Direct recognition of allogeneic transplants requires donor derived dendritic cells.</div><div>B. Indirect recognition occurs only when MHC molecules are mismatched</div><div>C. HLA matching is more important for haemopoietic stem cells transplants than for liver transplants</div><div>D. HLA typing is not necessary in the autologous situation</div><div>E. A GvH response is never advantageous</div>

Answer 23

<div>In transplantation:<div>A. Direct recognition of allogeneic transplants requires donor derived dendritic cells. (TRUE)</div><div>B. Indirect recognition occurs only when MHC molecules are mismatched (FALSE)</div><div>C. HLA matching is more important for haemopoietic stem cells transplants than for liver transplants (TRUE)</div><div>D. HLA typing is not necessary in the autologous situation (TRUE)</div><div>E. A GvH response is never advantageous (FALSE)</div></div>

Question 24

The endogenous pathway of antigen presentation involves:<div>A. Mostly peptides derived from extracellular pathogens</div><div>B. Presentation of antigen on MHC class I molecules<br></br></div><div>C. Presentation of antigen to cytotoxic T cells</div><div>D. Presentation of antigen to T_H1 cells</div><div>E. Presentation of antigen to B cells</div>

Answer 24

“<div>The endogenous pathway of antigen presentation involves:<div>A. Mostly peptides derived from extracellular pathogens (FALSE)</div><div>B. Presentation of antigen on MHC class I molecules (TRUE)<br></br></div><div>C. Presentation of antigen to cytotoxic T cells (TRUE)</div><div>D. Presentation of antigen to T_H1 cells (FALSE)</div><div>E. Presentation of antigen to B cells (FALSE)</div></div><div><br></br></div>A - F; presents intracellular antigens, on MHC I molecules for CD8 cells. Proteins within the cytosole are continually being degraded into peptides by the proteasome. These peptides are moved from the cytosol into the ER via TAP [transporter associated with antigen processing]. Suitable peptides are then loaded onto partially folded MHC class I molecules in a process that is assisted by chaperone proteins known as the peptide loading complex [PLC]. Fully loaded MHC peptide complexes are released from the chaperones, pass through the golgi, and then follow the secretory pathway to the cell surface. See diagram.<br></br>D - F; Th1 cells are CD4 cells and so interact with MHC class II<br></br>E - F; B cells do not bind to antigen presented on MHC molecules. B cells binds antigen via its specific surface BCR/Ig and internalises it. The endocytosed antigen is then processed and presented on the surface MHC class II peptide complex. This peptide is then recognised by T helper cells which interacts with the MHC II molecules with its TCR. Also requires co-stimulatory moelcules to provide signal 2. This promote B cell proliferation, B cell survival signals and promotes Ig class switching. This interaction also leads to activation of the T cell.”

Question 25

Antigen presentation:

A. Professional antigen presenting cells include macrophages, dendritic cells and B-cells.

B. Co-stimulatory molecule expression is a defining feature of professional antigen presenting cells.

C. Foreign antigen presented by B lymphocytes is mainly taken up by phagocytosis.

D. Peptide anchor residues interact with pockets in the MHC peptide binding groove.

E. The proteasome generates the majority of peptides presented by MHC class II molecules

Answer 25

"

Antigen presentation:

A. Professional antigen presenting cells include macrophages, dendritic cells and B-cells. (TRUE)

B. Co-stimulatory molecule expression is a defining feature of professional antigen presenting cells. (TRUE)

C. Foreign antigen presented by B lymphocytes is mainly taken up by phagocytosis. (FALSE)

D. Peptide anchor residues interact with pockets in the MHC peptide binding groove. (TRUE)

E. The proteasome generates the majority of peptides presented by MHC class II molecules (FALSE)

C - F; B cells are non-phagocytic. They have BCRs that can interact with a wide variety of molecules in their native conformation. Antigen bound to the BCR is endocytosed and processed to be presented on MHC II molecules for presentation to B cells. 
E - F; the proteasome generates the majority of peptides presented by MHC class I molecules. Peptides presented on MHC II molecules are taken up into the cell by endocytosis and are then degraded into peptides by proteases. "

Question 26

MHC class II molecules

A. Are highly polymorphic and show more variation than TCR molecules

B. Are expressed on all cell types

C. Present peptides to CD4 restricted T cells

D. Can undergo somatic hypermutation

E. Are present on follicular dendritic cells

Answer 26

"

MHC class II molecules

A. Are highly polymorphic and show more variation than TCR molecules (FALSE)

B. Are expressed on all cell types (FALSE)

C. Present peptides to CD4 restricted T cells (TRUE)

D. Can undergo somatic hypermutation (FALSE)

E. Are present on follicular dendritic cells (FALSE)

A - F; they are highly polymorphic with many different alleles in the population - 9,342 protein variants. However, TCR molecules show the most variation with up to 10¹⁸ variants.
B - F; they are expressed on professional antigen presenting cells e.g. macrophages, B cells and dendritic cells. Class II molecules can be induced to be expressedon other cells in the presence of IFNgamma.
D - F; B cells undergo somatic hypermutation in their production of antibodies. Point mutations are introduced into heavy and light chain variable regions. This involves deamination of cytosine to uracil by the enzyme activation induced cytidine deaminase (AID). Antibodies with increased affinity are selected by affinity maturation. The mutation rate is abut 1/1000 BP per cell division.
E - F; they are present on dendritic cells NOT follicular dendritic cells. These two types of cell are from different lineages and are not related either structurally or functionally. "

Question 27

Regarding the MHC. 

A. Every individual possesses hundreds of different MHC I and II alleles

B. A particular MHC molecule will be specific for only one peptide

C. Exposure of DCs to PAMPs decreases surface expression of MHC class I molecules

D. Polymorphism in MHC class I molecules is concentrated in the a1 and a2 domains

E. MHC class I molecules binds peptides in the ER

Answer 27

"

Regarding the MHC. 

A. Every individual possesses hundreds of different MHC I and II alleles (FALSE)

B. A particular MHC molecule will be specific for only one peptide (FALSE)

C. Exposure of DCs to PAMPs decreases surface expression of MHC class I molecules (FALSE)

D. Polymorphism in MHC class I molecules is concentrated in the a1 and a2 domains (TRUE)

E. MHC class I molecules binds peptides in the ER (TRUE)

A - F; every individual possesses 3 MHC class I isotypes and 3 MHC class II isotypes and hence each individual has 6 different MHC class molecules. I = A, B, C. II = DP, DQ, DR.
B - F; a particular mHC molecule will be specific for anchor residues, and for particular lengths of peptide but it will not be specific for the residues in between these anchor residues meaning that it can present a wide array of peptide fragments.
"

Question 28

Pathogen associated molecular patterns

A. Can evolve quickly to counter new pathogens

B. Are present in vertebrate hosts

C. Are specific to the individual organism

D. Can recognise double stranded RNA

E. Include lipopolysaccharide

Answer 28

"

Pathogen associated molecular patterns

A. Can evolve quickly to counter new pathogens (FALSE)

B. Are present in vertebrate hosts (FALSE)

C. Are specific to the individual organism (FALSE)

D. Can recognise double stranded RNA (FALSE)

E. Include lipopolysaccharide (TRUE)

A - F; they are highly conserved which helps our cells to detect PAMPS regardless of the exact type of pathogen present/or regardless of slight mutations between different pathogens.

B - F; they are a sign of infection hence are not normally present. DAMPS are normally present. 
C - F; they are highly conserved across different classes of organisms. This means that we don't need as many different PRRs to detect them.
D - F; PRRs can recognise double stranded RNA. Double stranded RNA might however act as a PAMP e.g. from RNA viruses e.g. TLR3.

"

Question 29

Prions:

A. Are infectious proteins that can be transmitted by ingestion

B. Have a mainly alpha-helical structure in the disease form of the protein

C. Are expressed at high levels in the CNS

D. Are inactivated by UV irradiation

E. Can cause progressive neurodegenerative diseases

Answer 29

"

Prions:

A. Are infectious proteins that can be transmitted by ingestion (TRUE)

B. Have a mainly alpha-helical structure in the disease form of the protein (FALSE)

C. Are expressed at high levels in the CNS (TRUE)

D. Are inactivated by UV irradiation (FALSE)

E. Can cause progressive neurodegenerative diseases (TRUE)

B - F; the PrP has a mainly beta-sheet structure in the disease form. This form is very stable (resistant to protease digestion) and catalyses the conversion of the normal protein. 
D - F; infectivity is not destroyed by irradiation that would destroy nucleic acids
"

Question 30

Influenza Virus

A. can have filamentous or spherical morphology

B. encode an RNA-dependent DNA polymerase
C. require a high pH environment to fuse with cellular membranes
D. encode 3 viral envelope proteins
E. cause seasonal epidemics due to the process of antigenic drift

Answer 30

"

Influenza Virus

A. can have filamentous or spherical morphology (TRUE)

B. encode an RNA-dependent DNA polymerase (FALSE)
C. require a high pH environment to fuse with cellular membranes (FALSE)
D. encode 3 viral envelope proteins (TRUE)
E. cause seasonal epidemics due to the process of antigenic drift (TRUE)

B - F; encode an RNA-dependent RNA polymerase made up of PB1, PB2 and PA polypeptides
C - F; they require a low pH
"

Question 31

Measles virus:

A. Is controlled by a subunit vaccine

B. Is highly infectious

C. Is enveloped

D. Can infect neurons

E. Is a cell associated virus

Answer 31

"

Measles virus:

A. Is controlled by a subunit vaccine (FALSE)

B. Is highly infectious (TRUE)

C. Is enveloped (TRUE)

D. Can infect neurons (TRUE)

E. Is a cell associated virus (TRUE)

A - F; by a live vaccine - all MMR are live
"

Question 32

Viruses that often establish chronic or latent infections include:

A. Foot and mouth disease virus

B. Rotavirus
C. Herpes simplex virus
D. Human cytomegalovirus
E. Hepatitis C virus

Answer 32

Viruses that often establish chronic or latent infections include:

A. Foot and mouth disease virus (FALSE)

B. Rotavirus (FALSE)
C. Herpes simplex virus (TRUE)
D. Human cytomegalovirus (TRUE)
E. Hepatitis C virus (TRUE)

Question 33

Gene transfer by transduction is mediated by

A. Sex pili

B. Contact between bacteria

C. Bacteriophages

D. Naked DNA

E. Bacterial plasmids

Answer 33

"

C. Bacteriophages

- Transduction = via bacterial viruses e.g. bacteriophages

- Transformation = from dead (lysed) bacteria

- Conjugation = direct transfer between two bacteria via sex pili

"

Question 34

Pathogenic bacteria have evolved in close association with their host. Which is the most accurate description? They…

A. Are simple eukaryotic cells

B. Use mitochondria to generate energy

C. Are often obligate intracellular parasites

D. Do not undergo meiosis

E. Have a large number of introns in their genome

Answer 34

"

D. Do not undergo meiosis

- Bacteria are prokaryotes not eukaryotes

- They do not contain mitochondria because they don't have intracellular membrane bound organelles

- Some bacteria are obligate intracellular parasites - e.g. chlamydia. However, most can make ATP and protein and hence are not intracellular pathogens. Chlamydia has lost many of the metabolic enzymes and pathways and is adapted to scavenge essential metabolites from the host cell. 

- Bacteria do not have as many introns as eukaryotes

"

Question 35

Bacterial endotoxins are clinically important. Which best describes a property of endotoxins?

A. They are more heat stable than exotoxins

B. They are lipopolysaccharide

C. They are characteristic of gram-positive bacteria

D. They are cytolysin

E. They are secreted from the bacterial cell

Answer 35

"

A. They are more heat stable than exotoxins

- Endotoxin is lipid A which is a component of the gram-negative bacterial cell wall e.g. lipopolysaccharide (e.g. it is not a lipopolysaccharide, it is a component of lipopolysaccharides)

- It is released from dying bacteria and is a major alarm signal that triggers a wide-ranging immune response

- It is not a pathogen specific toxin since lots of bacteria have this lipid A; however, it is unique to bacteria and hence acts as a good host alarm signal

- Endotoxin overload can occur as large numbers of bacteria die e.g. in septicaemia, causing septic shock

- Exotoxins are pathogenic protein toxins secreted by bacteria and can be denatured by heat to produce non-toxic immunogenic forms used for vaccination

- Exotoxins can be divided into cytolysins and intracellular enzymatic toxins

"

Question 36

Cholera toxin is an important virulence factor. Which best describes a property of the protein? It… 

A. Enters host cells by receptor-mediated endocytosis

B. Is a single polypeptide

C. ADP ribosylates translation elongation factor 2

D. Cleaves synaptobrevin

E. Causes net influx of chloride ions into host cells

Answer 36

"

A. Enters host cells by receptor-mediated endocytosis

- V. cholerae colonises the small intestine via fimbrial adhesin

- V. cholerae is a gram -ve curved rod with a polar flagellum

- The principal disease symptoms are caused by secreted cholera toxin (CTX)

- CTX genes are carried on a bacteriophage integrated into the bacterial chromosome and are co-regulated with adhesin and other genes by a HAP signal transduction system

- Toxin structure is AB5; B binds to the host receptor GM1-ganglioside and is taken up via receptor-mediated endocytosis and retrograde transport to the ER where A and B dissociate; active A subunit is translocated into the host cell cytosol

- Not a single peptide because of the AB5 structure e.g. 6 peptides in total

-A subunit is an ADP-ribosylase and it activates stimulatory G protein Gs, fixing it on the on state e.g. inhibits GTP hydrolysis thereby leading to GTP bound to G protein

- Results in uncontrolled high levels of cAMP which leads to increased activity of the CFTR channel and causes net efflux of Cl- from the epithelial call

- Ion imbalance leads to water/electrolyte loss (up to 20 L/day) into the lumen which leads to copious watery diarrhoea (rice water), shock, collapse and cardiac failure

- Diphtheria toxin ADP-ribosylates translation elongation factor-2

- Synaptobrevin is cleaved by botulinum and tetanus [botox on peripheral nerves and tetanus on centrla nerves]

"

Question 37

Helicobacter pylori

A. Survives by producing spores

B. Is motile by flagella

C. Is associated with colon cancer

D. Causes antibiotic-associated diarrhoea

E. Produces uric acid

Answer 37

"

B. Is motile by flagella

- H. pylori causes gastric and duodenal ulcuers [90% are associated w/ infection]

- Half of the human poopulation is colonised

- It colonises the mucin layer near gastric mucosal cells in the lower stomach antrum - although only a few percent will get ulcers

- Very motile by means of flagella and binds to cells via adhesins

- Gram negative bacteria that is spiral shaped

- Neutralises acid by urease which splits urea into ammonia, thereby raising the pH, which makes the gastric mucous less viscous and so it is easier for the H. pylori to swim to the epithelium

- Associated with gastric cancer; chronic inflammation may expose proliferating mucosal stem cells to dietary carcinogens and generate mutagenic reactive oxygen, in addition, bacterial effector CagA delivered into gastric epithelial cells interferes with signalling pathways and may lead to increased cell proliferation

- Destroys epithelial cells via VacA which is a pore-forming vacuolating cytotoxin; secreted by H. Pylori, it inserts into the membrane to form anion selective channels that are endocytosed; these disturb the ion balance of late endosomes and water flows in, swelling the endosomes to form characteristic vacuoles

- H. Pylori also attracts PMNs via stimulating epithelial cells to produce IL-8

- C. diff induced diarrhoea is associated with antibiotic use

- Spore forming bacteria: clostridium tetani, clostridium perfringens, clostridium botulinum, bacillus anthracis [e.g. some bacteria produce dormant endospores to survive the environment]

"

Question 38

Which statement most accurately relates to corynebacterium diphtheriae infection?

 

A. Toxic shock syndrome can develop

B. Toxin production is repressed in the presence of iron

C. Cytotoxic T cells play a major role in host defence

D. The toxin gene is carried on a plasmid

E. Bacteria induce their own uptake into epithelial cells

Answer 38

"

B. Toxin production is repressed in the presence of iron

- Corynebacterium diphtheriae is a gram-positive rod

- Not many cases any more due to toxoid vaccination but it is still a major kill worldwide, especially in children

- It has a close counterpart in animals e.g. C. ulcerans and C. pseudotuberculosis which leads to a range of diseases in sheep, goats, cows and horses

- Produces diphtheriae toxin - DTX

- Toxin gene is carried on bacteriophage, not a plasmid; DTX gene is controlled by a bacterial transcription factor; DtxR which represses gene expression when bound by iron e.g. transcription is switched on in the host where the concentration of free iron is low

- Bacteria colonise the nasopharyngeal epithelium and secrete A-B toxin which results in intense local inflammation and damage to mucosal cells and growth of bacteria in inflammatory exudate, and formation of pseudo-membrane which occludes the airway

- Toxin can lead to irregular heartbeat, coma and death

- Bacteria don't actually enter the epithelial cells themselves; but the A-B single polypeptide binds to the HB-EGF receptor (via B peptide); host furin protein then nicks the A-B but A-B remains covalently attached via a disulphide bridge; toxin is then taken up by endocytosis; acidification of the endosome then occurs; by V-ATPase; then B-dependent translocation of A across vesicle into the cytosol; in the cytoplasm the disulphide bond is reduced and A is released  and blocks protein synthesis by ADP-ribosylating translation elongation factor-2 (EF-2)

- Toxic shock syndrome is associated with Staph. Aureus infection

- Cytotoxic T cells are important in viral infections/intracellular infections but C. diptheria is not an intracellular pathogen

- Not all strains of corynebacterium diphtheriae are toxigenic --> depends whether they have the bacteriophage with the DTX on within it or not

"

Question 39

Regulation of cAMP levels is important for controlling ion balance. Which of the following induce elevated cAMP levels without targeting host adenylate cyclase.

A. Shigella

B. Vibrio cholerae

C. Bordella pertussis

D. Enterotoxigenic E. Coli

E. Clostridium difficile

Answer 39

"

C. Bordella pertussis

- B. Pertussis (whooping cough) and bacillus anthracis (anthrax) actually produce toxins that are adenylate cyclases, thereby not directly interacting with the host AC but mimicing it

- B. Pertusis also produces a toxin that does ADP-ribosylate regulators of host AC as well

- Enterotoxigenic E. Coli (ETEC) produces cholera-like enterotoxin LT (labile toxin) which causes a similar diarrhoea in children in developing countries, as well as travellers' diarrhoea

- V. Cholerae induces high cAMP via increasing the activity of the G-protein and thereby indirectly increasing host AC activity

- C. Difficile toxins glycosylate small GTPases involved in regulation of signal transduction - it disrupts actin cytoskeleton and tight junctions

- Shigella produces shiga toxin (produces bacterial dysentery) which is a glycosidase that depurinates 28s rRNA. Blocks protein synthesis of the host cell. 

"

Question 40

Some diseases are characteristically spread by propagated outbreaks. Which of the following is least likely to be spread by this route?

A. Dysentery

B. Cholera

C. Whooping cough

D. Typhoid

E. Bubonic plague

Answer 40

"

E. Bubonic plague

- Propagated outbreaks, where host-to-host transmission results in ever greater numbers of infection is common for whooping cough, TB, gonorrhoea, dysentery, cholera and typhoid

- Dysentery + Cholera are spread by faecal-oral route via water

- Whooping cough is spread by respiratory tract (air-borne droplets)

- Typhoid is spread by faecal-oral route

- Bubonic plague is spread from rodents (point/continuous source) to humans, in which the disease becomes pnuemonic --> and then can cause propagated outbreaks, but this is penumonic plague NOT bubonic plague

"

Question 41

Which of the following most accurately describes properties of pathogenic bacteria

A. Genomes contain between 300 and 600 genes

B. Genomes are usually DNA but sometimes RNA

C. Genomes contains blocks of virulence genes separated by introns

D. Transduction of genes is effected by bacteriophage

E. Transduction of genes requires contact between bacteria

Answer 41

"

D. Transduction of genes is effected by bacteriophage

- Genomes typically contains ~ 4,500 genes (Salmonella)

- Genomes are DNA

- There are not many introns in bacterial genomes

- Transduction of genes is via bacteriophages

- Conjugation allows for transferral of plasmid; bacteria contact via a pilus

"

Question 42

Cholera toxin

A. Undergoes retrograde transport

B. Is injected into host cells

C. Inhibits host protein synthesis

D. Disrupts control of host protein production

E. Is related to an E.Coli heat stable toxin

Answer 42

"

A. Undergoes retrograde transport

- The toxin is endocytosed into the epithelial cells of the host; not injected

- Diphtheria toxin ADP-ribosylates EF-2 to inhibit host protein synthesis

- Is related to E. Coli heat labile toxin [enterotoxin]; e.g. not heat stable

- Acts to alter ion balance, but doesn't directly act upon host protein production just cAMP

"

Question 43

Diptheria is a respiratory tract infection 

A. Is caused by a gram-positive rod-shaped bacterium

B. Diphtheria toxin acts by activating host protein synthesis

C. Diphtheria toxin activity requires endosome acidification

D. Infection is especially common in patients with cystic fibrosis

E. Diptheria toxoid vaccination is ineffective in the developing

Answer 43

"

C. Diphtheria toxin activity requires endosome acidification

- It is caused by a gram positive rod but not rod shaped; tennis racket/club shaped 

- Diptheria toxin acts by inhibiting host protein synthesis

- Acidification of the endosome (by a V-ATPase proton pump) triggers B-dependent translocation of A across the vesicle membrane into the cytosol where it can then inhibit EF-2 and hence inhibit elongation

- Pseudomonas infection is particularly common in people with CF; P. aeruginosa biofilms form in the lungs

- Diptheria toxoid vaccination is effective in preventing the disease; and has significantly lowered rates where it is used

"

Question 44

Which of these bacteria best fits the criteria of being an obligate aerobe and also have an outer cell membrane

A. Salmonella typhi

B. Shigella dysenteriae

C. Pseudomonas aeruginosa

D. Corynebacterium diphteriae

E. Staphylococcus aureus

Answer 44

"

C. Pseudomonas aeruginosa

- Outer cell membrane = gram negative

- Salmonella = gram negative + facultative anaerobe

- Shigella = gram negative + facultative anaerobe

- Pseudomonas = gram negative + obligate aerobe

- Corynebacterium diphtheriae = gram positive + facultative anaerobe

- Staphylococcus aureus = gram positive + facultative anaerobe

- TB is also an obligate aerobe

"

Question 45

Transmission from animals is characteristic of human disease outbreaks caused by which bacteria?

A. Vibrio cholerae

B. Salmonella typhi

C. Shigella dysenteriae

D. MRSA

E. Yersinia pestis

Answer 45

"

E. Yersinia pestis

- Yersinia pestis causes pneumonic plague; infecting bacteria in flea spread through lymphatics to form enlarged lymph nodes which we call buboes; then haemorrhagic inflammation occurs with spread of the bacteria to the blood and the lungs; can also cause meningitis, septiciaemia, and multi-organ failure. The necrotic lesions give it the name black death.

- Cholera is spread by the faecal oral route via infected water

- Salmonella is spread by food/water borne infection

- MRSA is caused by staph aureus, an opportunistic infection which is often nosocomial e.g. hospital acquired; e.g. it is spread via inanimate objects e.g. in burns, surgical wounds and following catheterization

- Shigella dysenteriae is spread via faecal oral route of infected water

"

Question 46

The bacterial cell wall is a major target for antimicrobial agents. Which of these binds to bacterial D-ala-D-ala containing tetrapeptides?

A. Trimethoprim

B. Methicillin

C. Lysozyme

D. Vancomycin

E. Beta-lactamase

Answer 46

"

D. Vancomycin

- Vancomycin is a glycopeptide that binds to D-Ala-D-Ala and blocks access to the transpeptidase, preventing crosslinking of PG; vancomycin resistant gram-positive pathogens produce different peptidoglycan biosynthesis enzymes that synthetise D-Ala-D-Lac alternative peptide crosslinks

- Trimethoprim inhibits DHFR (dihydrofolate reductase) thereby inhibiting folate synthesis [conversion of dihydrofolic acid to tetrahydrofolic acid] which is an essential step in the synthesis of nucleotides

- Methicillin - a penicillin type antibiotic that inhibits the transpeptidase enzyme and hence inhibits cell wall synthesis

- Lysozyme is produced in host tears and splits bacterial peptidoglycan

- Beta-lactamase is not an antibiotic but a produce produced by bacteria that hydrolyse beta-lactam based antibiotics e.g. penicillins to produce penicilloic acid

"

Question 47

These bacteria are the most common cause of chronic disease resulting in immune mediated pathology?

A. Mycobacterium leprae

B. Clostridium tetani

C. ETEC

D. Vibrio cholerae

E. Treponema pallidum

Answer 47

"

A. Mycobacterium leprae

- Mycobacterium leprae causes leprosy which is chronic, the condition involves granuloma formation

- C. tetani doesn't produce chronic infection

- ETEC (enterotoxigenic E. Coli) causes travellers' diarrhoea, but doesn't produce chronic infection

- Cholera doesn't produce chronic infection

- Treponema pallidum causes syphilis --> which is chronic, however, it is not as immune mediated as mycobacterium leprae e.g. in mycobacterium leprae there is granuloma formation etc. whereas there are no granulomas in syphilis

"

Question 48

Which of these is most important with respects to pathology associated with bacterial endotoxin?

A. Is a secreted protein

B. Is a component of lipopolysaccharide

C. Activates macrophages

D. Forms pores in host cell membranes

E. Contributes to the inflammation characteristic of Salmonellosis

Answer 48

"

C. Activates macrophages

- It is not a secreted protein; LPS is released from dead bacteria

- Acute inflammation is triggered by the lipid A component of gram-negative bacterial LPS

- LPS released is bound by LPS-binding protein and is delivered to macrophage receptors, CD14 and TLR4, which triggers signalling pathways that activate cytokine genes

- Lipid A is unique to gram negative bacteria and so it is a very good host alarm signal, triggering a strong innate immune response - overload can lead to sepsis/shock

- It does contribute to the inflammation characteristic of Salmonellosis but this is not the most important aspect of its pathology since it is not specific to salmonella infection

- Salmonella induces host ctoskeletal rearrangement via SP-1 encoded needle and effectors SipA, SipC, it forces entry directy via the apical surface epithelial cells of the distal ileum and proximal colon; it then remains within membrane bound vacuolles in a replicate niche and multiplies. It is then released from epithelial cells by lysis and induces inflammation principally by LPS-lipid A, producing gastroenteritis

- Lipid A does not form pores in host cell membranes

"

Question 49

Which of the following best describes features of infection by Mycobacterium Tuberculosis? It…

A. Is caused by a gram positive rod shaped bacteria

B. Results in damage to the lungs by a bacterial exotoxin

C. Is resolved by a strong TH17 response

D. Requires an effective IL-12 response for control

E. Is spread to humans from cattle

Answer 49

"

D. Requires an effective IL-12 response for control

- Mycobacterium is neither gram +ve or -ve because the waxy impermeable cell envelope made up of mycolic acid prevents staining and also making it more resistant to immune attack; it is therefore referred to as acid fast and is stained with Ziehl-Neelsen stain

- It results in damage to the lungs through granuloma formation and cavitation; persisting M. tuberculosis leads to type IV granulomatous inflammation in which activated macrophages are surrounded by fibroblasts and a few lymphocytes ‘wall off’ the pathogen. Granulomas show ongoing tissue destruction (necrosis), repair (fibrosis, scarring) and inflammation

- There is a separate mycobacterium bovis which is in cattle and is closely related - it can be spread through unpasteurised milk but this is still M. Bovis and not M. Tuberculosis

- M. Tuberculosis is an obligate aerobe

- Bacteria spread by small droplets and are ingested by alveolar macrophages; virulent strains can resist intracellular killing by establishing safe uptake pathways that arrest phagosome-lysosome fusion; the bacteria can cross the alveolar epithelium and enter the lymphatics, drain to the regional lymph nodes and may enter the blood to disseminate around the body to produce new foci of infection

- Lysis of host cells and dissemination is facilitated by small secreted ESAT6 protein, that forms pores to interfere with macrophage signalling pathways e.g. down-regulates ROS

- When infection persists there is a shift as CD4+ TH2 cells produced in addition to protective Th1 cells; however, normally Th1 cells activate macrophages via IFNy. TNFalpha and NO are produced and bacteria are phagocytosed and killed and cell-mediated immunity is established

- IL-12 is important in inflammatory Th1 responses - it is released by activated macrophages and leads to activation of NK cells, as well as differentiation of CD4 T cells into Th1 cells

- Th17 responses are involved in the removal of extracellular bacteria and fungi at epithelial surfaces

"

Question 50

Which of the following is least likely to cause disease of the GI tract by attaching to endothelial cell using pili?

A. EPEC E. coli

B. Salmonella typhi

C. Clostridium difficile

D. Vibrio cholerae

E. Vac A expressing H. pylori

Answer 50

"

C. Clostridium difficile

Only gram negative bacteria form pili and all of the other bacteria in the list are gram negative and hence C. diff must be the answer since this is gram positive

"

Question 51

Bacterial virulence genes are important for host colonisation. Which best describes a genetic feature that allows bacterial effector gene expression to be coordinated? Genes are…

A. Located on introns

B. Located on pathogenicity islands

C. Located on plasmids

D. Subject to global regulation

E. Spread between bacteria without cell-to-cell contact

Answer 51

"

B. Located on pathogenicity islands

- Bacteria don’t have introns in their genome

- Genes required for infection and survival in the host are grouped on pathogenicity islands; they have evolved by integration of transposons, plasmids and bacteriophage and incorporation of transformed DNA; they typically have a high G+C content that differs from the surrounding chromosomal DNA; they increase dissemination of virulence traits and facilitate virulence gene co-regulation

"

Question 52

Diptheria is generally well controlled by vaccination. Which feature is most important for the pathogenicity of diphtheria toxin?

A. The toxin causes bacterial secretion of a pseudomembrane

B. The toxin undergoes retrograde transport to the endoplasmic reticulum

C. The toxin requires a low iron environment for release of the A subunit

D. The diphtherias vaccine prevents infection with corynebacterium diptheriae

E. The toxin is encoded by a gene carried on a bacterial virus

Answer 52

"

E. The toxin is encoded by a gene carried on a bacterial virus

- The formation of the pseudomembrane in the airway leads to occlusion which can lead to death

- The toxin requires a low iron environment for transcription e.g. DTX gene is controlled by bacterial transcription factor DtxR which represses gene expression when bound by iron (Fe)

-  The toxin undergoes retrograde transport but not via the ER; it is taken in via an endosome and then is released into the cytosol

- Vaccination does not prevent infection, but means that the individual has pre-existing immunity to infection

- The toxin is encoded on a bacteriophage gene that is then integrated into the genome; hence some strains are not pathogenic because they don’t have the virulence gene incorporated; non-toxigenic strains

"

Question 53

Which of the following statements about cholera is untrue

A. Can be endemic

B. Can be epidemic

C. Can be pandemic

D. Involves bacterial entry into host cells of the GI tract

E. Produces diarrhoea as a result of a protein toxin

Answer 53

D. Involves bacterial entry into host cells of the GI tract

Question 54

Which of the following statements about salmonella species is true. They…

A. Produce spores

B. Have between 250 and 300 genes

C. Have a capsule

D. Are obligate intracellular pathogens

E. Can grow anaerobically

Answer 54

"

E. Can grow anaerobically

- They do not produce spores

- They do not have a capsule

- They have around 4,500 genes

- They are not obligate intracellular pathogens

- They are facultative anaerobes

"

Question 55

Which of the following does not cause food-borne disease

A. Clostridium botulinum

B. Clostridium tetani

C. Salmonella enterica

D. Listeria monocytogenes

E. Staphylococcus aureus

Answer 55

"

B. Clostridium tetani

- You get tetanus from soil getting into a wound via spores

- Listeria can be found in unpasteurized cheese, salad and hence why pregnant women don’t eat this cheese

- Salmonella is food-borne via chicken/eggs

- C. botulinum can be via food e.g. old home canned food

- Staphylococcal food poisoning is also a thing

"

Question 56

Which of the following statements about streptococcus pyogenes is most accurate

A. Survives by producing endospores

B. Forms clusters of cells

C. Is a coccobacillus

D. Causes fasciitis

E. Can be an intracellular pathogen

Answer 56

"

D. Causes fasciitis

- Can cause pharyngitis, tonsillitis, scarlet fever, necrotizing fasciitis, erysipelas and impetigo

- Is a gram positive cocci

- Staphylococci forms clusters of cells

- Extracellular pathogen

- Does not produce spores

"

Question 57

Which of the following do not specifically inhibit protein synthesis

A. Trimethoprim

B. Tetracycline

C. Chloramphenicol

D. Streptomycin

E. Gentamycin

Answer 57

"

A. Trimethoprim

- Trimethoprim - inhibits DHFR

- Tetracycline - inhibits binding of amino acyl tRNA to ribosome; 30S subunit; inhibits translation

- Chloramphenicol - inhibits peptidyl transferase activity of 50S subunit; inhibits translation

- Streptomycin + gentamycin - alter conformation of 16S rRNA in 30s subunit so inhibits tRNA binding and hence translation

"

Question 58

Which of the following infections is most likely to be involved in granuloma formation

A. Neisseria meningitidis

B. Pseudomonas aeruginos

C. Mycobacterium leprae

D. Bordetella pertussus

E. All bacteria producing superantigens

Answer 58

"

C. Mycobacterium leprae

- Leprosy also causes granuloma formation and causes chronic bacterial infection

- Neisseria meningitidis causes meningitis --> it can colonize several percent of the population, but meningococcal disease is uncommon. Neisseria meningitidis strains have sialic acid capsules, an example of host mimicry. Polysaccharides are weakly immunogenic, but anti-capsular antibodies can protect against specific serotypes. 

- Pertussus causes whooping cough but this is an acute severe disease of young children which involves colonisation of the respiratory epithelium, damage to epithelial cells by LPS lipid A, and production of pertussis toxin and adenylate cyclase. Produces fever and bronchitis. This and toxin action on neurons promotes paroxysms of coughing. Life-threatening in infants with underlying disease, can lead to neurological sequelae.

- Superantigens can lead to shock due to SAg bridging weakly interacting MHC II molecules and TCRs by binding outside the normal antigen-binding pocket. This leads to activation of useless T cells by promoting tighter binding and stronger singalling in T cells. This results in a cytokine storm.

"

Question 59

Which of these diseases/infections is least likely to be spread by propagated outbreaks

A. Gonorrhoea
B. Influenza
C. Meningitis
D. Botulism
E. Typhoid

Answer 59

"

D. Botulism

- Botulism is caused by food poisoning --> so unless you also eat the toxins then you will not get it from an infected person

- C.f. all the other which can be transmitted between humans 

- Typhoid is spread is spread by water via the faecal-oral route

- Gonorrhoea is sexually transmitted

- Influenza is spread via inhalation of air-droplets and is easily spread

- Meningitis may be caused by several pathogens, some of which colonize the nasopharynx asymptomatically (carriers can therefore be important in outbreaks). Pathogens that can cause meningitis include:

1) Neisseria meningitidis

2) Haemophilus influenza type B (Hib)

3) Streptococcus pneumoniae 

4) E. Coli 

"

Question 60

Which of the following is the most accurate statement

A. Lipid A is part of the bacterial cell wall peptidoglycan

B. Obligate aerobic bacteria have a mitochondrion

C. Pathogenic bacteria have between 8,000 and 12,000 genes

D. Bacteria take up free DNA by transduction

E. Salmonella uses the usher secretion pathway

Answer 60

"E. Salmonella uses the usher secretion pathway

All gram negative bacteria use the usher secretory pathway to get things from the periplasm to the outer membrane

- Lipid A is a component of LPS not PG

- Bacteria don't have mitochondria 

- Bacteria take up free DNA released by dead cells by transformation

- Pathogenic bacteria can have a variety of genome sizes e.g. Salmonella genome is ~ 4,500 genes but chlamydia has a smaller genome ~ 900 genes and makes up for the loss of proteins via being an obligate intracellular bacteria

"

Question 61

The following cause infections of the respiratory tract

A. Bordetella pertussis and streptococcus pyogenes

B. Salmonella typhi and Yersinia pestis

C. Legionella pneumophila and staphylococcus aureus

D. Vibrio cholerae and streptococcus equi

E. Pseudomonas aeruginosa and Helicobacter pylori

Answer 61

"

A. Bordetella pertussis and streptococcus pyogenes

- Pertussis causes whooping cough.

- Streptococcus pyogenes can produce a number of different things including pharyngitis + Scarlet fever + Necrotising fasciitis, puerperal fever, eryseipela and impetigo.

- Salmonella typhi causes gastroenteritis.

- Yersinia pestis causes bubonic plague (can then spread to pneumonic plague).

- Legionella pneumophila causes an atypical pneumonia.

- Streptococcus equi causes strangles in horses which is a severe upper respiratory tract infection.

- Pseudomonas aeruginosa can cause conjunctivitis, UTI, infect burns, wounds. It can also produce lung infection.

- Helicobacter pylori causes gastric ulcers + cancer.

- Staphylococcus aureus can cause erysipelas, impetigo, skin infection and toxic shock syndrome. Also causes severe diarrhoea and vomitting.

- Cholera causes diarrhoea and vomitting

"

Question 62

The following specifically inhibit synthesis of the bacterial cell wall

A. Tetracyclin

B. Ciprofloxacin

C. Trimethoprim

D. Cephalosporin

E. Neomycin

Answer 62

"

D. Cephalosporin

- Tetracyclin inhibits the amino-acyl tRNA binding to the 30S subunit thereby inhibiting translation

- Ciprofloxacin is a fluoroquinolone that inhibits DNA topoisomerase II (DNA gyrase) + IV this inhibits replication and transcription since these enzymes are important in controlling DNA topology

- Trimethoprim inhibits DHPR thereby interferring with folic acid and thus pyrimidine synthesis 

- Cephalosporin is a beta-lactam antibiotic

- Neomycin is an aminoglycoside like gentamicin and alters the conformation of teh 16S rRNA in the 30S subunit where the ribosome 'reads' mRNA and recruits aminoacyl-tRNA. This inhibits tRNA selection and polypeptide elongation. 

"

Question 63

Which of these bacteria is least likely to be considered part of the normal microflora of humans

A. Bacteroides fragilis

B. Staphylococcus epidermidis

C. Salmonella typhi

D. Streptococcus viridans

E. Streptococcus pneumoniae

Answer 63

"

C. Salmonella typhi

- Bacteroides fragilis --> part of normal gut microflora

- Staphylococcus epidermidis --> part of the normal human skin flora + sometimes mucosal too

- Salmonella typhi

- Streptococcus viridans --> commensal found in the mouth/gut/genital region

- Streptococcus pneumoniae --> this is the cause pneumonia/meningitis, however, it can also be a commensal

"

Question 64

Which of the statements regarding Typhoid is least accurate

A. Can be endemic

B. Can be epidemic

C. Is characterised by the action of a protein toxin

D. Involves survival of bacteria in host macrophages

E. Can involve a host carrier state

Answer 64

"

C. Is characterised by the action of a protein toxin

It is a protein toxin, however, the toxin does not appear to influence disease severity; strains that are deficient in the toxin seem to be pretty much indistinguishable from those producing the toxin and hence typhoid is not really characterised by its actions.

- Typhoid causes typhoid fever 

- Salmonella typhi replicates in macrophages and is spread locally and systemically via blood stream to liver and spleen; but not always

- Severe symptoms are caused by typhoid toxin (CDT - cytolethal distending toxins) that cleaves DNA and response to LPS lipid A

- Bacteria are shed in bile, returning to the intestine and environment

- Carriers can be important (typhoid Mary)

- Up to 50% of the world is in a typhoid endemic region

- Spread by water via faecal-oral route

- Can be a point source or a continuous source outbreak, or propagated outbreaks (if the carrier for example is not isolated)

"

Question 65

Which statements about Infection with Mycobacterium tuberculosis is most accurate? Infection

A. Is eliminated by formation of epithelioid granulomas

B. Is preventable by a toxoid vaccine

C. Leads to ingestion of the bacteria by macrophages

D. Leads to immunity through development of specific antibodies

E. Is detected by a type 2 hypersensitivity reaction in response to BCG

Answer 65

"

C. Leads to ingestion of the bacteria by macrophages

- The response to persistance (not elimination) of TB is via type IV granulomatous inflammation in which aggregates of activates macrophages (which may differentiate to epithelioid cells or multi-nucleate giant cells), surrounded by fibroblasts and a few lymphocytes that 'wall-off' the pathogen

- Granulomas show ongoing tissue destruction (necrosis), repair (fibrosis, scarring) and inflammation 

- Leads to caseous necrosis aids spread of the bacterium (Miliary TB)

- Antibodies against TB are not very effective due to the mycolic acid coat --> instead the immune response to is primarily via Th1 cells that activate macrophages and produce IFNgamma

- It is detected by a type IV hypersensitivity reaction in the Mantoux test against a small amount of injected tuberculin into the skin of the forearm e.g. memory Th1 cells release cytokines that recruit and activate macrophages

- The vaccine is M. bovis not a toxoid vaccine (e.g. a vaccine made from a toxin that has been made harmless but that still elicits an immune response) 

"

Question 66

Which of the following statements about Salmonella is least accurate?

A. Salmonella can cause food-borne infections

B. Can be typed using the O cell surface lipopolysaccharide antigen

C. Can invade intestinal epithelial cells

D. Can resist killing by macrophages

E. Can cause gastric ulceration

Answer 66

"

E. Can cause gastric ulceration

- Salmonella is found in chicken and eggs

- Salmonella is a gram negative bacteria meaning that it will have the O cell surface LPS antigen; see diagram

- Salmonella can induce host cytoskeletal rearrangement and forces entry directly via the apical surface of epithelial cells of the distal ielum and proximal colon; requires SPI-1 encoded needle and effectors e.g. the actin binding SipA and SipC

- Salmonella remains within a membrane-bound vacuole - a 'replicative niche' and multiplies

- Released from epithelial cells by lysis and induces inflammation via LPS lipid A

- It is then taken up by macrophages where it replicates. It survives intracellulary by switching on SPI-2 genes encoding effectors that inhibit maturation of the phagolysosome and confer resistance to defensins and oxidative burst (pumps, superoxide dismutase, catalase)

"

Question 67

Which of the following statements about E. Coli infections of the GI tract is most accurate

A. ETEC colonises by fimbrial (pili) adhesions
B. EPEC produces a cholera-like enterotoxin LT (labile toxin)
C. EHEC produce yellow colonies on McConkey agar
D. ETEC produces a shiga-like toxin (SLT) that accentuates inflammation
E. E. Coli 0157 is an ETEC found in beefburgers

Answer 67

"

A. ETEC colonises by fimbrial (pili) adhesions

- ETEC colonises by fimbrial pili adhesions --> it is a common cause of diarrhoea in children as well as Traveller's diarrhoea. It is spread by contaminated water

- Labile toxin is an E. coli entertoxin e.g. ETEC

- E. coli are lactose fermenting and hence they will be red on McConkey agar
- EHEC produces shiga like toxin that is a glycosidase that depurinates 28S rRNA thereby blocking protein synthesis
- E. Coli 0157 is an EHEC found in beef

"

Question 68

Which of the following statements about diphtheria toxin is most accurate? The toxin:

A. Forms large pores in host cell membranes

B. Acts as an ADP-ribosylase in the host cell

C. Targets epithelial cells of the intestine

D. Is produced by all strains of cornebacterium diphtheriae

E. Targets the host cell adenylate cyclase

Answer 68

"

B. Acts as an ADP-ribosylase in the host cell

- It ADP-ribosylates elongation factor 2 thereby preventing protein synthesis

- It is not produced by all strains; just the toxigenic strains that have been infected with the bacteriophage carrying the toxin 

- It is a respiratory tract disease that is air-borne --> it colonises the nasopharyngeal epithelium, not the intestine

"

Question 69

The following do not cause disease by infecting the GI tract

A. Vibrio cholerae

B. Salmonella typhimurium

C. Helicobacter pylori

D. Clostridium botulinum

E. Shigella dysenteriae

Answer 69

"

D. Clostridium botulinum

- C. botulinum does not infect the GI tract

- It grows anaerobically in food and produce botulinum toxin that is then ingested

- Botulinum toxin is a neurotoxin

- Bacterial dysentery, caused by invasive shigella causes highly infectious disease characterised by acute inflammation of the colon and low-volume diarrhoea containing blood mucus and PMNs. Damage is caused directly by the shiga toxin and indirectly by the inflammatory response

"

Question 70

Which of the following is false - the bacterial cell wall is:

A. Disrupted by lysozyme

B. Disrupted by tetracycline

C. Disrupted by penicillin

D. Made of peptidoglycan

E. Strengthened with a pentaglycine cross-link

Answer 70

"

B. Disrupted by tetracycline

- Tetracyline binds to the amino-acyl tRNA binding of the 30S subunit thereby inhibiting elongation

- Lysozyme in tears splits bacterial peptidoglycan

"

Question 71

Which statement regarding Salmonella is most accurate. Salmonella:

A. Like shigella causes zoonotic infections

B. Causes disease by secreting many enzymatic toxins

C. Can enter epithelial cells by inducing cytoskeletal change

D. Has a single cell membrane

E. Causes toxic shock syndrome

Answer 71

"

C. Can enter epithelial cells by inducing cytoskeletal change

- It is caught via ingesting chicken and eggs but is not directly zoonotic

- Toxic shock syndrome is caused by Staph. Aureus

- It has an inner and outer membrane because it is a gram negative bacteria

- It causes disease primarily by release of Lipid A which leads to gastroenteritis

- It can enter epithelial cells by inducing cytoskeletal change; in order to do this is uses SPI-1 (pathogenicity island) needle and injects SipA and SipC which bind to actin; this occurs within the distal ileum and the proximal colon; within these cells salmonella remains within membrane bound vacuoles where it multiplies.

"

Question 72

Which statement regarding bacterial cells is least accurate? They

A. often contain extrachromosal DNA

B. divide by binary fission

C. are haploid

D. possess intermediate filaments

E. contain mitochondria

Answer 72

E. contain mitochondria

Question 73

Which statement regarding bacterial exotoxin is least accurate? They...

A. Are secreted from the bacterial cell

B. Are heat labile

C. Are proteins

D. Have similar effects regardless of the bacterial species of origin

E. May be encoded by plasmids

Answer 73

"

D. Have similar effects regardless of the bacterial species of origin

- There are lots of different types of bacterial toxins which are all exotoxins

- They are all secreted

- They are heat labile because they are proteins --> can be used to form non-toxic immunogenic proteins

- Two broad groups

1) cytolysins

2) intracellular enzymatic toxins

"

Question 74

Which statement regarding bacterial evasion of host defences is least accurate? They...

A. Subvert macrophage function

B. Avoid phagocytosis

C. Integrate DNA into the host genome

D. Destroy antibody

E. Undergo phase variation

Answer 74

"

C. Integrate DNA into the host genome

- Retroviruses can integrate their DNA into the host genome

- Lots of bacteria subvert macrophage function e.g. Yersinia injects multiple effectors into macrophages:

1) YopT, a protease that targets small GTPases to disrupt the cytoskeleton

2) YopP an acetyl transferase that inhibits signalling, triggering apoptosis. 

- Bacteria can inactivate antibody e.g. secretory IgA is cleaved by specific proteases of mucosal pathogens e.g. strep pneumonia, H. influenzae, N. gonorrhoea, N. meningitidis

- Bacteria can avoid phagocytosis by shielding with antiphagocytic capsules e.g. polysaccharides:

1) Steric hindrance e.g. physical block

2) Non-immungenic polysaccharide e.g. sialic acid

3) Lack of affinity for complement factor B: C3b not formed

- Bacteria can shut off or switch on expression of surface antigens via phase variation e.g. Salmonella flagelline

1) Rearrangement of an invertible promoter region, flanked by recombination sequences recognised by site-specific DNA recombinase

"

Question 75

Which statement regarding bacterial virulence genes is least accurate?

A. Can be acquired by transformation

B. May be grouped in pathogenicity islands

C. May be carried on plasmids

D. Are involved in the establishment of maintenance of infections

E. Evolve less rapidly than other genes

Answer 75

"

E. Evolve less rapidly than other genes

- Transformation is when genes are taken up from DNA released from dead/lyesd bacteria

- They will involve more rapidly since this is important in evading host responses

"

Question 76

Which statement regarding tetanus toxins is most relevant to its function?

A. it is produced by spores of C. tetani in anaerobic wounds

B. the 'A' chain acts on peripheral nerves, causing spastic paralysis

C. it is a protease cleaving synaptobrevin

D. it inhibits a small GTPase in the CNS, disrupting neurotransmitter release

E. The 'A' chain undergoes retrograde transport and blocks release of inhibitor neurotransmitters in the CNS, causing flaccid paralysis

Answer 76

"

C. it is a protease cleaving synaptobrevin

- Tetanus neurotoxin is made during anaerobic growth of the pathogen in a wound

- The 'A' chain acts on central nerves/intermediate neurons

- It reduces neurotransmitter release from the inhibitory interneuron

- It causes spastic paralysis

"

Question 77

Regarding these infections which statement is least accurate?

A. Streptococcus pyogenes is beta-haemolytic, forms gram-positive chains, and is Lancefield-typed by cell surface M proteins

B. Pneumonia and meningitis are caused by streptococcus pneumoniae and haemophilus influenza both of which have a capsule and secrete IgA protease

C. Protection against whooping cough caused by Bordetella pertussis is provided by the DPT combination vaccine

D. Diphtheria toxin is a single polypeptide A-B toxin that glycosylates translation elongation factor EF-2, inhibiting protein synthesis

E. Antigen-antibody complexes resulting from streptococcus pyogenes infection cause type III hypersensitivity, specifically glomerulonephritis

Answer 77

"

D. Diphtheria toxin is a single polypeptide A-B toxin that glycosylates translation elongation factor EF-2, inhibiting protein synthesis

- Diphtheria toxin ADP-ribosylates EF-2

- Streptococcus pyogenes causes pharyngitis acutely but can lead to glomerunephritis and rheumatic fever more long term

"

Question 78

This organism is an obligate anaerobe that produces endotoxin:

A. Salmonella typhi

B. Clostridium tetani

C. Bacteroide fragilis

D. Vibrio cholera

E. Clostridium sporongenes

Answer 78

"

C. Bacteroide fragilis

- Salmonella typhi is an gram negative facultative anaerobe

- Clostridium tetani is a gram positive obligate anaerobe

- Bacteroides fragilis is a gram negative obligate anaerobe; see diagram

- Vibrio cholera is a gram negative facultative anaerobe

- Clostridium sporongenes is a gram positive obligate anaerobe

"

Question 79

In pathogenic bacteria, which statement is most accurate?

A. Growth involves haploid chromosome replication and binary fission

B. Virulence genes are typically distributed randomly on the chromosome

C. Between 4000 and 6000 genes are arranged without introns in the nucleus

D. Transformation involves bacterial pili

E. Transduction requires contact between bacterial cells

Answer 79

"

A. Growth involves haploid chromosome replication and binary fission

- Virulence genes are found on pathogenicity islands

- Pathogenic bacteria can vary in the number of genes they have ~500-7,500 (depending to an extent on whether they are intracellular or extracellular bacteria)

- Transformation involves taking up genes that have been released by lysed bacteria

- Transduction requires contact via pili between bacterial cells

"

Question 80

Regarding TB, which statement is least accurate?

A. M. tuberculosis is spread by small droplets and is ingested by alveolar macrophages

B. Chronic granulomatous disease is typically resolved by a Th1 response

C. M. tuberculosis resists macrophages by means of an alignate polysaccharide coat

D. Caseous necrosis aids spread of the pathogen and is associated with miliary TB

E. The presence of immunity is detected as a T cell response by the tuberculin skin test

Answer 80

"

C. M. tuberculosis resists macrophages by means of an alignate polysaccharide coat

- Pseudomonas aeruginosa produces an alginate polysaccharide 'slime' coat during lung infections; this protects the bactera in the biofilm from the host immune response and antimicrobials

"

Question 81

Which of the following most typically causes propagated outbreaks of food-borne disease in humans?

A. Streptococcus aureus

B. E. coli 0157 (EHEC)

C. Helicobacter Pylori

D. Vibrio Cholerae

E. Clostridium difficile

Answer 81

"

B. E. coli 0157 (EHEC)

- E. Coli 0157 is commonly found in beef

- Staph. aureus can grow in custard and processed meats

- Cholera is from water borne

- C. Diff is antibiotic associated not food associated

- H. Pylori doesn't produce propagated outbreaks of disease

"

Question 82

In antibiotic action and resistance which statement is most accurate?

A. TolC is an inner membrane transporter in efflux pumps conferring multi-drug resistance

B. Vancomycin mimics D-Ala-D-Ala crosslinks to inhibit peptidoglycan synthesis, and resistance to it is mediated by altered crosslinks

C. Rifampicin and ciprofloxacin both act on the DNA-dependent RNA polymerase

D. Trimethoprim and sulphonamide inhibit dihydrofolate reductase and thus folate synthesis

E. Chloramphenicol acts at the bacterial ribosome to prevent translation, and resistance to it typically involves antibiotic modification by an acetyl transferase

Answer 82

"

E. Chloramphenicol acts at the bacterial ribosome to prevent translation, and resistance to it typically involves antibiotic modification by an acetyl transferase

- TolC is a transporter which spans the periplasm and the outer membrane. It confers multi-drug resistance e.g. in gram negative pseudomonas and E. Coli; see diagram

- Penicillin mimics the D-Ala-D-Ala peptidoglycan crosslink. It binds to the active site of the transpeptidase irreversibly inhibiting PG crosslinking. 

- Vancomycin binds to D-Ala-D-Ala and resistance is mediated by production of D-Ala-D-Lac via different peptidoglycan biosynthetic enzymes

- Rifampicin blocks bacterial DNA-dependent RNA polymerase but ciprofloxacin is a fluoroquinolone that inhibits topoisomerases

- Trimethoprim inhibits DHFS but sulphonamides inhibit DHPS

- Resistant bacteria produce acetyl transferases that modify (acetylate) chloramphenicol + aminoglycosides (gentamicin, neomycin) to prevent ribosome binding

"

Question 83

Regarding gastrointestinal infections which statement is least accurate?

A. Helicobacter pylori is a motile gram-negative bacteria that causes inflammation of the gastric mucosa and gastric ulcers

B. ETEC causes traveller's diarrhoea colonizes host cells by modulating the actin cytoskeleton to form pedestals and secreting a cholera-like ADP-ribosylating toxin

C. Cholera toxin A subunit short-circuits adenylate cyclase control, so disturbing the activity of membrane ion pumps

D. C. Diff causes inflammation of the colonic mucosa and secretes glycosylating toxins that disrupt epithelial tight junctions

E. Shiga toxin is a glycosidase that blocks host cell protein synthesis, causing kidney damage

Answer 83

"

B. ETEC causes traveller's diarrhoea colonizes host cells by modulating the actin cytoskeleton to form pedestals and secreting a cholera-like ADP-ribosylating toxin

- EPEC + EHEC produces pedestal formation: the bacterium uses specialised needles to 'inject' proteins into the host cell, including a specific Tir (translocated intimin receptor). Tir then binds to the bacterium via bacterial surface protein intimin and promotes actin polymerisation

- ETEC produces LT (labile toxin) which is the cholera like ADP-ribosylating toxin. It causes traveller's diarrhoea.

- C. Diff secretes a toxin that glycosylates small GTPases involved in signal transduction - this disrupts the actin cytoskeleton and tight junctions

- Shiga toxin produced by Shigella that causes dysentery is a glycosidase that depurinates 28s rRNA and blocks protein synthesis. This leads to renal failure. Shiga like toxin is produced by EHEC and also damages the kidney.

"

Question 84

Regarding bacterial toxins, which statement is most accurate:

A. Pneumolysin, streptolysin O and E. Coli haemolysin all form pores in the cell membranes

B. Staphylococcal and botulinum toxins are both superantigens causing food poisoning

C. Endotoxin (lipid A) can be converted to a protective vaccine by heating

D. C. perfringens alpha-toxin is a phospholipase that can be detected by its actions on egg yolk agar (ELEK test)

E. Pertussis and cholera toxins are multimeric ATP-ribosylate enzymes that target adenylate cyclase

Answer 84

"

A. Pneumolysin, streptolysin O and E. Coli haemolysin all form pores in the cell membranes

- Pneumolysin = streptococcus pneumoniae, streptolysin O + S = streptococcus pyogenes, haemolysin = E. Coli (UPEC)

- Staph aureus produces a superantigen but botulinum toxin is not a superantigen. Staph aureus bacteria are ingested in food but do not colonise while botulinum toxin is found in food. 

- Exotoxins can be converted to a vaccine via heating e.g. toxoid vaccines

- Clostridium perfringens does produce an alpha-toxin. It enzymatically degrades membrane phospholipids. However, the ELEK test is used to looks for toxigenic strains of corynebacteria diphtheria. 

- Pertussis and cholera toxins produce multimeric ADP-ribosylating enzymes that target adenylate cyclase

"

Question 85

Among pathogenic bacteria which statement is most accurate?

A. Mycoplasma do not gram stain as they do not have a cell wall, but rather a waxy lipid coat

B. Treponema pallidum is a spiral shaped spirochaete that causes tick-borne Lyme's disease

C. Bacillus anthracis and cornebacterium diphtheriae are spore-forming bacteria producing enzymatic protein toxins

D. Botulinum toxin cleaves a neuronal SNARE so preventing release of acetylcholine, causing flaccid paralysis that is exploited in cosmetic procedures

E. Shigella is a zoonotic infections that also transmits person-to-person

Answer 85

"

D. Botulinum toxin cleaves a neuronal SNARE so preventing release of acetylcholine, causing flaccid paralysis that is exploited in cosmetic procedures

A - Mycobacteria are referred to as 'acid-fast' because they are difficult to destain due to a waxy impermeable cell envelope (mycolic acid) that makes the pathogen resistant to disinfectants and protects it from immune attack; they do however still have a cell wall

B - Treponema pallidum causes syphillis. It is a spirochaete (e.g. spiral shaped). Lyme's disease is caused by Borrelia Burgdorferi.

C - Bacillus anthracis is a pore forming bacteria but cornebacterium diphtheriae is not.

E. - Shigella is a very infectious disease that transmits via the faecal-oral route. Man is the main reservoir.

"

Question 86

NK cells 

a. kill target cells using perforin and granzymes 

b. kill target cells by antibody dependent cell cytotoxicity (ADCC) 

c. kill virus infected cells through recognition of MHC class I molecules presenting virus-derived peptides 

d. have inhibitory receptors that recognise classical MHC class I molecules 

e. activate macrophages by secreting IFN-γ

Answer 86

A - T; perforin forms pores in the cell membrane and allows apoptosis inducing granzymes into the cell

B - T; NK cells have FcyRIII receptor that binds to Ab Fc regions --> this binding activates the NK cell and leads to release of perforin and granzymes

C - F; Th1 cells do this. Virally infected cells therefore decrease MHC1 exression but NK cells recognise this as 'missing self' and kill cell

D - T; thereby not killing normal host 

E - T

Question 87

In the complement system 

A. generation of C3(H2O) is a reversible reaction 

B. C4b can covalently attach to pathogen surfaces 

C. mannose-binding lectin is a soluble pattern recognition receptor 

D. deficiency in factor I results in uncontrolled alternative pathway activation and C3 depletion 

E. individuals deficient in complement component C1 are predisposed to immune-complex disease

Answer 87

A - ?; it's hydrolysis so probably if you remove H2O again?

B - T; C1s can cleave C4 to expose reactive thioester group which can covalently attach C4b to pathogen surface

C - T; it binds close knit arrays of mannose and fucose residues found on microbial surfaces of bacteria, yeast and fungi and some viruses (important in lectin pathway)

D - T; because factor I is a serine protease that degrades C3b and C4b (with help of cofactors MCP and factor H)

E - T; also C2 and C4 deficiency

Question 88

Pattern Recognition Receptors 

a. include TLR4 which recognises components of Gram–negative bacterial LPS 

b. include NOD2 which recognises muramyl dipeptide and is often mutated in individuals with Crohn’s disease 

c. recognise either pathogen associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs), but not both 

d. are all transmembrane signalling receptors 

e. that recognise bacterial cell wall components often activate proinflammatory responses through NF-kB

Answer 88

"A - T; homodimer

B - T; NOD1 and 2 recognise fragments of peptidoglycan from bacteria. NOD2 detects muramyl dipeptide (found in most bacteria) released from gut microbiota and is involved in gut homeostasis

C - F

D - F; some are soluble e.g. CRP or MBL

E - T; bacterial produce MYD88 --> NF-kB and AP-1 while viral produce TRIF --> IRFs

"

Question 89

Of the T cell subsets 

A. TH17 cells promote neutrophil recruitment and are involved in defence against extracellular bacteria and fungi 

B. TH2 cells express GATA3 

C. TH1 cells promote responses against intracellular bacteria and protozoa 

D. TH2 cells express MHC class I 

E. natural regulatory T cells (Tregs) are thought to be educated in the periphery when they meet antigen

Answer 89

A - T

B - T

C - T

D - T; and MHC class II

E - F; natural Tregs develop in the thymus. Tregs have an intermediate affinity for self antigens in MHC molecules and are not deleted by negative selection

Question 90

In transplantation 

A. hyperacute rejection can be complement-mediated 

B. HLA matching is very important in liver transplants 

C. syngeneic transplants are transplants between two genetically identical individuals 

D. minor transplantation antigens may be derived from MHC molecules 

E. chronic rejection may be due to gradual damage to the blood vessels of the graft

Answer 90

A - T; results from pre-existing Abs e.g. ABO or HLA antigens that are expressed on ECs. Tissues are damaged by complement activation, coagulation and leakage of fluid, as well as aggregation of platelets that block the microvasculature

B - F; very important in haemopoietic stem cells, and significant in kidney and heart

C - T

D - T; minor antigens (H antigens) are proteins that vary in sequence and where one of the allomorphs contains a peptide which binds to the MHC of the recipient. 

E - T; can occur years later. May involve immune respones against blood vessels leading to ischaemia and loss of function. It may be due to type III hypersensitivity due to IgG antibodies against allogeneic HLA class I molecules on the graft, forming immune complexes that deposit in blood vessels. Indirect allo-recognition is important for chronic rejection as B cells binding shed donor HLA proteins are helped by T cells. Kidney damage can also affect loss via non-immune mechanisms. 

Question 91

The following purified virus genomes are infectious if artificially introduced into cells 

A. herpes simplex virus 

B. vaccinia virus 

C. poliovirus 

D. influenza virus 

E. HIV

Answer 91

"

The following purified virus genomes are infectious if artificially introduced into cells 

A. herpes simplex virus (TRUE)

B. vaccinia virus (TRUE)

C. poliovirus (TRUE)

D. influenza virus (FALSE)

E. HIV (FALSE)

D - F; -ve sense are non-infectious as need virally encoded RNA-dependent RNA pol

E - F; retroviruses are non-infectious as require virally encoded reverse transcriptase

"

Question 92

These are obligate anaerobes producing endospores and enzymatic toxins 

A. Clostridium difficile 

B. Clostridium botulinum 

C. Bacteriodes fragilis 

D. Streptococcus pneumoniae 

E. Clostridium tetani

Answer 92

These are obligate anaerobes producing endospores and enzymatic toxins 

A. Clostridium difficile (TRUE)

B. Clostridium botulinum (TRUE)

C. Bacteriodes fragilis (FALSE)

D. Streptococcus pneumoniae (FALSE)

E. Clostridium tetani (TRUE)

Question 93

In gastrointestinal infections 

a. Helicobacter pylori is a motile Gram-negative bacterium for which VacA is a key virulence factor 

b. ETEC causes travellers’ diarrhoea by bacteria entering host intestinal cells and inducing inflammation 

c. Listeria invades intestinal cells by receptor-mediated endocytosis to establish an intracellular infection, but it can become systemic and cross the blood-brain barrier 

d. Clostridium difficile secretes toxins that disrupt the actin cytoskeleton and epithelial tight junctions 

e. Shiga toxin inhibits Rho/Ras GTPases, causing kidney damage

Answer 93

A - T; pore-forming vacuolating cytotoxin

B - T; via fimbrial pili adhesins. Spread by contaminated water.

C - T

D - T; TcdA and TcdB that are small glycosylases leading to diarrhoea and inflammation of colonic mucosa. Cell damage is indirect via inflammation and pseudomembrane formation.

E - F a glycosidase that depurinates 28S rRNA thereby blocking protein synthesis but does cause renal failure

Question 94

The following are pro-thrombotic 

A. microparticles 

B. plasminogen activator inhibitors 

C. nitric oxide 

D. fibrin 

E. Von Willebrand factor

Answer 94

The following are pro-thrombotic 

A. microparticles (TRUE)

B. plasminogen activator inhibitors (TRUE)

C. nitric oxide (FALSE)

D. fibrin (TRUE)

E. Von Willebrand factor (TRUE)

Question 95

The following statements are true 

A. Bcl2 is a pro-survival protein 

B. P53 inactivates p21 

C. the APC gene is often mutated by frameshift mutations 

D. Bcr-Abl is formed as the consequence of a chromosomal inversion 

E. Ras proteins are activated by GTP hydrolysis

Answer 95

The following statements are true 

A. Bcl2 is a pro-survival protein (TRUE) 

B. P53 inactivates p21 (FALSE)

C. the APC gene is often mutated by frameshift mutations (FALSE)

D. Bcr-Abl is formed as the consequence of a chromosomal inversion (FALSE)

E. Ras proteins are activated by GTP hydrolysis (FALSE)

Question 96

Which gene/genes are mutated in Lynch Syndrome?

A. BRCA 1/ BRCA 2

B. Rb1

C. KRAS

D. APC

E. MLH1/ MLH2

Answer 96

E. MLH1/ MLH2

Question 97

Which statement is true?

A. BCL-2 is pro-apoptotic

B. Oncogene mutations are loss of function

C. Telomeres lengthen with each cell division 

D. Activation of the Wnt signalling pathway leads to B-catenin degradation. 

E. Rb1 acts at the G1/S checkpoint

Answer 97

E. Rb1 acts at the G1/S checkpoint

Question 98

Which statement is true? 

A. BRAF is classically mutated in breast carcinomas 

B. E-cadherin is a DNA repair protein 

C. MYC is a tumour suppressor gene 

D. The translocation (8;14) is known as the Philadelphia chromosome  

E. Isocitrate dehydrogenase (IDH) mutations leads to a block in cell differentiation

Answer 98

E. Isocitrate dehydrogenase (IDH) mutations leads to a block in cell differentiation

Question 99

Which statement is true? 

A. RAS acts in the nucleus to regulate the cell cycle 

B. TMPRSS2-ERG is a fusion gene is found in ~50% of leukaemias

C. Cyclin D1 complexes with CDK2 to regulate Rb1 

D. PTEN is often over expressed in cancers

E. BCR-ABL fusion protein is a tyrosine kinase

Answer 99

E. BCR-ABL fusion protein is a tyrosine kinase

Question 100

Which statement is false? 

A. Xeroderma pigmentosum patients lack excision repair

Β. Dimethyl nitrosamine is a carcinogen found in meat products 

C. Aflatoxin B1 is produced by Aspergillus flavus 

D. Aristolochic acid commonly causes lung cancer  

E. Beta-naphthylamine is a bladder carcinogen

Answer 100

D. Aristolochic acid commonly causes lung cancer  

Question 101

Which of the following does not cause cancers in humans?

A. EBV

B. HBV

C. HHV8

D. HTLV1

E. CMV 

Answer 101

E. CMV 

Question 102

Regarding complement 

A. C1q and mannose binding lectin (MBL) participate in the alternative pathway 

B. self cells are protected by decay accelerating factor (DAF) and properdin 

C. C3 is the central component of the complement system

D. C3a and C5a cause anaphylactic shock by systemic stimulation of mast cells 

E. C3b, C-reactive protein (CRP) and MBL are opsonins

Answer 102

A - F; MBL is lectin and C1q is classical

B - F; properdin is a positive regulator of C3bBb. DAF does protect and dissociates classical and alternative C3 convertases.

C - T

D - T

E - T

Question 103

Inflammation 

a. symptoms include calor, rubor, tumor, dolor 

b. involves the pro-inflammatory cytokines IL-1, IL-6 and tumour necrosis factor (TNFα) 

c. leads to the chemokine CXCL8 attracting mast cells 

d. occurs only in response to a pathogen 

e. from a systemic infection can lead to TNFα in the blood, giving rise to septic shock

Answer 103

A - T

B - T; IL-1beta, TNF-alpha, IL-6, CXCL8 and IL-12 all released by macrophages

C - F; neutrophils

D - F; pancreatitis for example

E - T

Question 104

Innate immunity 

a. can result from pattern recognition receptor recognition of pathogen associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) 

b. can be initiated by TLR4 and NOD-like receptor (NLR) recognition of LPS in endosomes 

c. stops most microorganisms before adaptive immunity is stimulated 

d. in response to viral RNA through TLR3 leads to interferon response factor 3 (IRF3) activation and production of type I interferon 

e. is necessary for the activation of adaptive immunity

Answer 104

A - T

B - F; NOD-like receptors are cytosolic that recognise both PAMPS and DAMPS

C - T; physical and chemical barriers prevent the vast majority of infections and then oroganisms that do penetrate are usually elminated by the innate immune system

D - T; TLR3 recognises ds viral RNA --> TRIF --> IFNs

E - T

Question 105

Regarding cell death 

a. apoptosis is always due to disease 

b. perforin and granzymes cause necrosis through the action of caspases 

c. the inflammasome activates caspases to cause apoptosis 

d. synergistic cytokines lead to cell survival while antagonistic cytokines lead to cell death 

e. necrosis initiates inflammation

Answer 105

A - F

B - F; apoptosis not necrosis

C - F; induces inflammation by causing caspase 1 to activate IL-1beta. Other caspases lead to apoptosis.

D - F (?); not totally sure but I think it's more about whether the responses of each cytokine promotes or hinders the other

E - T

Question 106

During an adaptive immune response 

a. antigen is carried in the lymph to regional lymph nodes

b. follicular dendritic cells (FDCs) hold antigen/antibody complexes on their surface for presentation to T cells 

c. B and T lymphocytes mainly enter lymph nodes via the afferent lymph 

d. T helper cells are found in germinal centres 

e. naïve T cells are activated by monocytes

Answer 106

A - T

B - F

C - F

D - T; T follicular helper cells

E - F; macrophages

Question 107

Regarding antibody generation 

A. the heavy chain is generated by splicing together different V, D and J exons 

B. IgG is the first antibody isotype to be produced 

C. somatic hypermutation requires the enzyme activation-induced cytidine deaminase (AID) 

D. B cells arriving in regional lymph nodes undergo VDJ recombination 

E. humans have an antibody repertoire estimated to comprise at least 10¹¹ different specificities

Answer 107

Regarding antibody generation 

A. the heavy chain is generated by splicing together different V, D and J exons (TRUE)

B. IgG is the first antibody isotype to be produced (FALSE)

C. somatic hypermutation requires the enzyme activation-induced cytidine deaminase (AID) (TRUE)

D. B cells arriving in regional lymph nodes undergo VDJ recombination (FALSE)

E. humans have an antibody repertoire estimated to comprise at least 10¹¹ different specificities (TRUE)

Question 108

MHC class I molecules 

a. are expressed on most cells of the body 

b. may be recognised by receptors present on NK cells 

c. present peptides to CD8+ cytotoxic T cells 

d. primarily present peptides derived from antigens that enter the cell by endocytosis 

e. use invariant chain as a chaperone

Answer 108

"A - T

B - T

C - T

D - F; this is MHC II e.g. non-self

E - F; MHC II associates with invariant chain within ER to prevent binding of ER peptides

"

Question 109

Regarding the immune system 

a. a haplotype refers to a combination of MHC alleles that are inherited together 

b. MHC polymorphism refers to variation in the sequence of genes at the same genetic locus 

c. co-dominant expression refers to the expression of both maternal and paternal MHC haplotypes on the same cell 

d. an anchor residue refers to an amino acid in the peptide-binding groove that binds the peptide 

e. antibody affinity is the strength of binding of a single antibody binding site to a single monovalent epitope on an antigen

Answer 109

"A - T

B - T; e.g. different alleles

C - T

D - T

E - T; c.f. avidity which is a measure of the strenght of interaction due to recognition of these polyvalent epitopes. IgM antibodies are low affinity but high avidity

"

Question 110

Professional antigen-presenting cells (APCs) 

A. include B lymphocytes, mast cells and dendritic cells 

B. express CD40 ligand and CD28 

C. express both MHC class I and MHC class II molecules 

D. originate from haematopoietic stem cells in the bone marrow 

E. can be activated in the absence of infection

Answer 110

Professional antigen-presenting cells (APCs) 

A. include B lymphocytes, mast cells and dendritic cells (FALSE)

B. express CD40 ligand and CD28 (FALSE)

C. express both MHC class I and MHC class II molecules (TRUE)

D. originate from haematopoietic stem cells in the bone marrow (TRUE)

E. can be activated in the absence of infection (TRUE)

Question 111

These statements about cytokines are correct 

A. CXCL8 is chemotactic for neutrophils 

B. interferon gamma (IFNγ) suppresses Th2 responses 

C. IL-6 induces the acute phase response 

D. IL-12 and IL-10 are pro-inflammatory 

E. IL-2 induces T cell proliferation

Answer 111

A - T

B - T

C - T

D - F; IL-10 is anti-inflammatory

E - F; IL-2 leads to Treg increase which decrease T cell proliferation

Question 112

Regarding tolerance 

A. autoimmune regulator (AIRE) expression allows peripheral antigens to be expressed in the thymus 

B. the majority of developing thymocytes fail positive selection 

C. high doses of soluble self-antigen leads to B cell anergy 

D. Tregs typically express the Foxp3 transcription factor 

E. immunodysregulation polyendocrinopathy enteropathy X-linked (IPEX) syndrome is due to defective AIRE expression

Answer 112

A - T; turns on peripheral genes in the thymus so that developing T cells may be exposed to their products

B - T

C - T

D - T

E - F; AIRE lack --> APECED while loss of FOXP3 leads to IPEX

Question 113

In the response to infection 

A. IL-4 and IL-13 are important cytokines for controlling helminth infections 

B. clearance of protozoan infections is generally helped by Th1 responses and hindered by Th2 responses 

C. NK cells release interferon gamma (IFNγ) 

D. most vaccines against virus infection protects via the generation of neutralizing antibody 

E. alternatively-activated macrophages are associated with Th2 responses

Answer 113

A - F; IL-5 and IL-13 are important for helmniths

B - T; anything intracellular = Th1

C - T

D - T

E - T

Question 114

Regarding immunity to pathogens 

A. cytotoxic T cells (CTLs) kill virus-infected cells 

B. Th1 cells are MHC class II-restricted and a major role is to activate macrophages 

C. Th17 cells promote neutrophil recruitment to sites of fungal infection 

D. TNFα stimulates dendritic cell activation and migration to lymph nodes 

E. type I interferons induce an antiviral state by preventing virus attachment to the host cell

Answer 114

"A - T

B - F

C - T

D - T

E - F; I'm not sure if this actually occurs?

"

Question 115

Regarding autoimmunity 

A. CD4+ Th1 cells are responsible for causing disease in the rat model of multiple sclerosis 

B. myasthenia gravis is caused by autoantibodies that activate the acetylcholine receptor 

C. environmental factors contribute about 50% of the susceptibility towards type I diabetes 

D. mutant MHC molecules are the most important genetic risk factor in autoimmune disease 

E. deficiencies in complement components predispose towards the immune complex disorder systemic lupus erythematosus (SLE)

Answer 115

A - T; CD4+ T cells specific to MBP (myelin basic protein) can subsequently cause disease if injected into another animal

B - F

C - T; MHC contributes other 25% and other genes the final 25%

D - F

E - T; C1, C2 and C4 deficiency all can lead to problems with immune complex disease

Question 116

Regarding transplantation 

A. hyperacute rejection can result from pre-existing antibody 

B. minor transplantation antigens result from allelic differences in proteins expressed in the recipient and donor 

C. a syngeneic transplant refers to a transplant between genetically identical individuals 

D. direct recognition of MHC alloantigen involves donor dendritic cells presenting antigen to and activating host T cells 

E. non-depleting anti-CD4 antibodies preferentially induce Th1 responses in transplant patients

Answer 116

A - T

B - T; where they vary in sequence and one of the allomorphs contains peptides which binds to the MHC II of the recipient and then stimulate a CD4 T cell alloreaction

C - T

D - T

E - F; a new antibody approach --> anti-CD4 non-depleting antibodies favours less harmful Th2 reponses over Th1

Question 117

Regarding blood groups 

A. an individual, who has not been previously transfused, is likely to have antibody to the O antigen blood group 

B. an individual with blood group AB is a universal donor 

C. the population frequency of AB individuals is low 

D. a child who is blood group A (phenotypically) may have a mother who is blood group O 

E. rhesus (Rh) antigen incompatibility is not a consideration in blood transfusions

Answer 117

A - F

B - F; universal receiver

C - T; 4%

D - T

E - F

Question 118

Regarding viruses 

a. the genome of a positive-strand RNA virus is complementary to mRNA 

b. influenza virus and rotavirus both have segmented RNA genomes 

c. a haemagglutination assay is performed by infecting red blood cells with influenza virus 

d. enveloped viruses can have icosahedral capsids 

e. electron microscopy can be used to observe viruses

Answer 118

A - F; negative strand RNA virus is complementary

B - T; influenza RNA ss -ve sense 8 segments while rotavirus is RNA ds with 11 segments

C - F; HA assay where you get haemagglutination from RBCs with sialic acid on their surface binding to HA of influenza

D - T; e.g. herpes simplex

E - T; used in counting virus particles especially if attached by antibody with gold bead attached

Question 119

Viruses modify infected cells 

a. herpesviruses encode a thymidine kinase (TK) enzyme that directly converts NTPs to dNTPs 

b. adenoviruses stimulate infected cells to enter the cell cycle 

c. poliovirus cleaves the cap of cellular mRNAs to promote viral gene translation 

d. measles virus spreads by causing infected cells to fuse with neighbouring cells 

e. poxviruses inhibit interferon signalling by blocking the pattern recognition receptors NF-κB and interferon response factor 3 (IRF3)

Answer 119

A - F; this is ribonucleotide reductase --> see diagram 

B - T

C - F; poliovirus encodes a protease that cleaves a component of the cap-binding complex so host mRNAs are not recognised, it is poxivurs that cleaves off the 5' capps completely

D - T
E - F; these are downstream of the PRRs --> however, pxo virus does target this parthway

Question 120

These viruses are sexually transmitted 

A. herpes simplex virus (HSV) 

B. hepatitis A virus 

C. Ebola virus 

D. human papilloma virus 

E. dengue virus

Answer 120

These viruses are sexually transmitted 

A. herpes simplex virus (HSV) (TRUE)

B. hepatitis A virus (TRUE)

C. Ebola virus (FALSE)

D. human papilloma virus (TRUE)

E. dengue virus (FALSE)

Question 121

Hepatitis B virus 

a. is spread via the faeco-oral transmission route 

b. causes persistent (chronic) infection 

c. has an RNA genome 

d. encodes a reverse transcriptase essential for virus replication 

e. can be effectively cured by drug treatment

Answer 121

A - F; contaminated needles, mother to child, during first years of life from family, sexually trasnmitted, blood products

B - T; 90% chronic if young and 10% if older

C - F; partially ds DNA

D - T; polymerase gene

E - F; effecive vaccine --> genetically engineered subunit cavvine (HBsAg)

Question 122

Regarding infection by human immunodeficiency virus (HIV): 

a. binding of the HIV attachment protein gp120 to cellular CD4 is sufficient to allow cell entry 

b. in rapid progressors, primary infection causes a sharp decline in the CD4+ cell count that rapidly rebounds to pre-infection levels 

c. rapid replication followed by virus-induced cell lysis destroys infected CD4+ cells 

d. during infection the ratio of capsid (gag) to envelope (env) protein expression is regulated by ribosomal frameshifting 

e. error-prone reverse transcription of HIV genomes means that the infection cannot be controlled by drug treatment

Answer 122

A - F; gp120 binds to CD4 and also CCR5 of CXCR4 chemokine co-receptors

B - F; CD4 count drops massively

C - T; in the early period the virus continues to replicate but is controlled by CD8+ CTL cells but then as the virus escapes from the immune system and replicates more extensively then more CD4+ cells are destroyed. 

D - F; gag to env is determined by splicing while gag-pol is frameshifting

E - F; reverse transcriptase inhibitors are important for HIV treatment e.g. AZT 

Question 123

A farm worker with a deep wound in his hand has developed tetanus. Which statement best describes the properties of tetanus toxin that give rise to these features? 

A. it is produced by spores of Clostridium tetani under anaerobic conditions 

B. it acts on peripheral nerves, causing spastic paralysis 

C. it is a peptidase cleaving small GTPases involved in signal transduction 

D. it is an adenylate cyclase, inactivating synaptobrevin 

E. it blocks release of inhibitory neurotransmitters

Answer 123

"

E. it blocks release of inhibitory neurotransmitters

A - spores are in relation to germination and not the toxin action although this statement is otherwise correct

B - it acts on spinal interneurons --> botulinum works on peripheral nerves

D - it cleaves synaptobrevin

"

Question 124

A woman presents with a sore throat and lesions on her tonsils after a few days. A throat swab is inoculated onto a sheep blood agar plate and a blood sample is taken. Which of the following provides the strongest specific evidence that the infection is caused by Streptococcus pyogenes? 

A. bacteria isolated from the infection site are Lancefield Group B based on cell surface carbohydrate antigens 

B. bacterial colonies show complete haemolysis on blood agar 

C. Gram staining reveals chains of Gram-positive rod-shaped cells 

D. bacterial colonies are small, translucent and concave 

E. titration of the patient’s serum against Streptolysin O reveals a high titre of antiStreptolysin O antibodies

Answer 124

"

E. titration of the patient’s serum against Streptolysin O reveals a high titre of antiStreptolysin O antibodies

A - they are Lancefield group A

B - true but not specific

C - cocci

D - sure... non-specific

"

Question 125

A middle-aged man is suffering from severe bloody diarrhoea and stomach cramps after attending a barbecue the previous evening. Which of the following would be the most likely causative agent? 

A. Staphylococcus aureus 

B. Salmonella enterica 

C. Escherichia coli 0157:H7 

D. Campylobacter jejuni 

E. Listeria monocytogenes

Answer 125

"

C. Escherichia coli 0157:H7 

A - skin infections --> in custard and processed meats but is superantigen and hence more sepsis type presentation?

B - chicken/egg

D - does produce bloody diarrhoea

E - it is food borne

"

Question 126

A virus infection of the liver in early childhood resulted in chronic liver inflammation and dysfunction as well as subsequent liver cancer in later life. Which of the following viruses is the most likely cause of these clinical outcomes: 

A. Hepatitis A virus 

B. Hepatitis B virus 

C. Hepatitis C virus 

D. Human cytomegalovirus 

E. Yellow fever virus

Answer 126

B. Hepatitis B virus 

Question 127

An outbreak of highly pathogenic influenza virus infection in a poultry farm was identified as the H5N1 strain of avian influenza virus. Which best describes the replication of the influenza virus genome: 

A. Negative sense single stranded RNA that is copied into positive sense RNA and then copied back into negative sense RNA genomes 

B. Negative sense single stranded RNA that is translated directly by the host ribosomes to generate the viral RNA polymerase required to copy the viral RNA genome 

C. Reverse transcription of a segmented negative sense RNA genome into DNA followed by transcription of the DNA copies into RNA genomes 

D. Segmented double stranded RNA that replicates in the cytoplasm through the activity of RNA-dependent RNA polymerase that is packaged into the virion 

E. Single-stranded DNA the replicates in the nucleus through the activity of host RNA polymerase II

Answer 127

A. Negative sense single stranded RNA that is copied into positive sense RNA and then copied back into negative sense RNA genomes 

Question 128

Scientists are studying a virus that infects lymphocytes and in rare circumstances can cause lymphoma. The virus that is most likely the focus of this research is: 

A. Cytomegalovirus 

B. Epstein-Barr Virus 

C. Human immunodeficiency virus 

D. Human papillomavirus 18 

E. Rous sarcoma virus

Answer 128

B. Epstein-Barr Virus 

Question 129

A key component of an innate immune response to viruses is the interferon pathway. The production of type I interferon in response to virus infection: 

A. Activates pathogen recognition receptor signalling cascades 

B. Causes rapid cell division due to the release of growth factors C. Is blocked by viral proteins that destroy MHC class I molecules 

D. Stimulates the synthesis of antiviral proteins such as protein kinase R 

E. Stimulates virus gene expression through the activation of the JAK-STAT signalling pathway

Answer 129

D. Stimulates the synthesis of antiviral proteins such as protein kinase R 

Question 130

Strain A mice make TH2-type responses in reaction to helminth infections. When infected with the murine whipworm Trichuris muris, what is the expected response? 

A. The mice will make IFNγ and clear the parasite 

B. The mice will make TNFα and suffer persistent infection 

C. The mice will make IFNγ, IL-4 and IL-13 and establish an asymptomatic longlived infection. 

D. The mice will make IL-4 and IL-13 and clear the infection 

E. The mice will make IL-4 and IL-13 and suffer persistent infection

Answer 130

D. The mice will make IL-4 and IL-13 and clear the infection 

Question 131

NK cells function in early defence against viruses that have not previously been encountered. They do this by: 

A. expressing activatory receptors that recognise the presence of MHC class I on infected cells. 

B. expressing activatory receptors that recognise virus encoded molecules. 

C. expressing activatory receptors that recognise self molecules induced in stressed cells. 

D. expressing Fc receptors that are capable of inducing perforin and granzymes release thereby inducing apoptosis of the infected cell. 

E. interacting with dendritic cells and initiating their migration to regional lymph nodes.

Answer 131

"

C. expressing activatory receptors that recognise self molecules induced in stressed cells. 

A - MHC I are everywhere so this doesn't make sense

B - virus tries to reduce expression of signals so don't think this makes sense

D - no because antibodies have not yet been made

E - they interact with macrophages

"

Question 132

The complement system is a collection of proteins that work together to provide protection from infection. Which statement most correctly describes the listed activity? 

A. C3, C4 and C5 are structurally related complement components that can covalently attach to pathogen surfaces 

B. DAF and factor H regulate C3 convertase activity by recruiting the protease activity of factor I 

C. patients deficient in C4 would be predicted to suffer from immune complex diseases such as contact hypersensitivity 

D. patients deficient in factor I would be predicted to suffer from over activation of the alternative pathway 

E. properdin is one of a group of complement control proteins that increase the activity of the complement pathways by stabilising the alternative pathway C3 convertase

Answer 132

"

D. patients deficient in factor I would be predicted to suffer from over activation of the alternative pathway 

A - they all attach but not sure if structurally related because maybe just C3 that has the internal thioester bond

B - Factor H and MCP are cofactors for factor I (soluble serine protease) and then degrades C3b and C4b. DAF dissociates classical and alternative C3 convterases and is present on host cells.

C - contact hypersensitivity is IV e.g T cell mediated but C4 deficiency does lead to immune-complex disease

E - it's not one of a group but it does do this

"

Question 133

The following viruses can transform cells 

A. Measles virus 

B. Rabies virus 

C. Papilloma virus 

D. Avian retrovirus 

E. Rhinovirus

Answer 133

The following viruses can transform cells 

A. Measles virus (FALSE)

B. Rabies virus (FALSE)

C. Papilloma virus (TRUE)

D. Avian retrovirus (TRUE)

E. Rhinovirus (FALSE)

Question 134

Concerning vaccines and vaccination 

a. smallpox eradication was facilitated by the development of a freeze-dried vaccine 

b. the Salk polio vaccine is a live attenuated vaccine 

c. the current hepatitis B vaccine is a genetically-engineered subunit vaccine 

d. an advantage of dead vaccines is that they induce humoral and cellular immunity 

e. eggs are used during the production of the influenza virus subunit vaccine

Answer 134

A - T

B - F; sabin is the live attenuated virus, salk is the inactivated virus

C - T; made by expressing HBsAg in yeast, purifying and injecting with adjuvant

D - F; live vaccines do this

E - T

Question 135

Regarding innate and adaptive immune responses to virus infection 

a. antibodies are usually involved in killing virus-infected cells 

b. cytoplasmic viral DNA can be sensed by pattern recognition receptors 

c. NK cells generally play a role late in infection once an antigen-specific CD8+ T-cell response has developed 

d. adenoviruses evade immune attack by preventing the transport of MHC class I molecules to the cell surface 

e. Epstein-Barr virus (EBV) encodes a viral cytokine that drives the immune system towards a Th1 response

Answer 135

A - F

B - T; TLR9 senses DNA viruses via unmethylated CpG rich DNA

C - F

D - T; block transport of peptides into ER for presentation, retain MHC I intracellularly so preventing their transport to the cell surface

E - F; vIL-10 --> Th2

Question 136

Regarding virus evolution and virus adaptation to their hosts 

a. virus infections associated with high morbidity and/or mortality are often zoonoses 

b. antigenic drift is the process by which influenza virus can acquire a HA gene from another influenza virus 

c. changes in the influenza PB2 gene can affect influenza virus replication efficiency in human cells 

d. acquisition of cellular genes from their hosts explains the existence of RNA virus genomes of over 100 kilobases (kb) 

e. following its introduction to Australia, myxoma virus mutated to become a more virulent pathogen

Answer 136

A - T

B - F

C - T; PB2 makes up part of the RNA-dependent RNA polymerase --> E = avian while K = human

D - F; the largest RNA viruses are just > 30 kb and these are due to proof reading activity of RNA polymerase

E - F

Question 137

Tetanus toxin 

a. is a single polypeptide A-B toxin produced by spores of Clostridium tetani in anaerobic wounds 

b. B subunit binds to a receptor on peripheral nerve membranes c. is a protease that cleaves synaptobrevin, blocking release of inhibitory neurotransmitters in the CNS 

d. A chain causes spastic paralysis by acting on peripheral nerves 

e. has the same proteolytic action as Botulinum toxin

Answer 137

A - T

B - T

C - T

D - F

E - T

Question 138

In respiratory infections 

a. Streptococcus forms hemolytic colonies, pairs or chains of Gram-positive cocci, and is Lancefield Group A 

b. Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenza, all secrete IgA protease and have polysaccharide capsules 

c. whooping cough is caused by Bordetella pertussis, which secretes ADPribosylating pertussis toxin and an adenylate cyclase toxin

d. Legionella pneumophila initiates propagated outbreaks from infected water (for example, from air conditioning units) 

e. diphtheria toxin ADP-ribosylates rRNA and thus inhibits translation

Answer 138

A - F; they all have different groups surface carbohydrates e.g. equi is C while pyogenes is A

B - F; they all have IgA proteases; they all have capsules (Neisseria = sialic acid one which not polysaccharide?)

C - T

D - T

E - F; ADP-ribosylates EF2 so preventing protein synthesis

Question 139

These are rod-shaped cells that have an outer membrane 

A. Salmonella typhi 

B. Clostridium perfringens 

C. Bacillus anthracis 

D. Bacteriodes fragilis 

E. Neisseria meningitidis

Answer 139

These are rod-shaped cells that have an outer membrane 

A. Salmonella typhi (TRUE)

B. Clostridium perfringens (FALSE)

C. Bacillus anthracis (FALSE)

D. Bacteriodes fragilis (TRUE)

E. Neisseria meningitidis (FALSE)

Question 140

In Gram-negative bacteria such as Escherichia coli 

a. haploid chromosome replication and binary fission result in population doubling times of two minutes in laboratory culture 

b. virulence genes can be located on bacteriophage, on plasmids and on pathogenicity islands 

c. LPS lipid A activates macrophages via CD14 and TLR4 

d. lipid A protects the cell from damage by the complement membrane attack complex 

e. DNA acquisition by conjugation requires bacterial contact, but transformation allows DNA uptake from the environment

Answer 140

A - F; every 20-30 mins

B - T; weird Q

C - T

D - F; LPS-O antigen and capsules prevent complement (lipid A is inner, not outer coat)

E - T

Question 141

In tuberculosis 

a. Mycobacterium tuberculosis is spread in propagated outbreaks by droplets, and survives in alveolar macrophages by inhibiting phagosome-lysosome fusion and resisting the oxidative burst 

b. chronic disease involves granulomatous inflammation which is often resolved by shifting to a Th2 response 

c. Mycobacterium bovis can be a zoonotic disease of humans 

d. mycobacteria grow slowly, they do not Gram stain due to cell wall lipid content, but are visible microscopically after Albert staining of cytoplasmic granules 

e. immunity is indicated by a cell-mediated response in the tuberculin skin test, and is conferred by the live attenuated DPT vaccine

Answer 141

A - T; TB, gonorrhoea, dysentery, cholera, typhoid all examples

B - F

C - T

D - F; Albert stain is for the polyphosphate granules of Corynebacterium diphtheriae
E - F; BCG

Question 142

Regarding antibiotics and bacterial resistance 

A. TolC is an inner membrane transporter in multidrug efflux pumps 

B. vancomycin mimics D-Ala-D-Ala crosslinks to inhibit peptidoglycan synthesis, but resistance is mediated by synthesis of alternative peptide crosslinks 

C. ciprofloxacin, a fluoroquinolone, inhibits gyrase and thus gene expression 

D. resistance to Trimethoprim, an inhibitor of folate synthesis, is conferred by expression of a ‘bypass’ dihydrofolate reductase 

E. tetracycline binds the 30S ribosomal subunit and blocks aminoacyl tRNA entry

Answer 142

Regarding antibiotics and bacterial resistance 

A. TolC is an inner membrane transporter in multidrug efflux pumps (FALSE)

B. vancomycin mimics D-Ala-D-Ala crosslinks to inhibit peptidoglycan synthesis, but resistance is mediated by synthesis of alternative peptide crosslinks (FALSE)

C. ciprofloxacin, a fluoroquinolone, inhibits gyrase and thus gene expression (TRUE)

D. resistance to Trimethoprim, an inhibitor of folate synthesis, is conferred by expression of a ‘bypass’ dihydrofolate reductase (TRUE)

E. tetracycline binds the 30S ribosomal subunit and blocks aminoacyl tRNA entry (TRUE)

Question 143

In gastrointestinal infections 

a. Helicobacter pylori is a motile Gram-negative rod that causes chronic inflammation of the gastric mucosa 

b. enterotoxigenic Escherichia coli (ETEC) causes diarrhoea in children and piglets, colonizing host cells by inducing Tir-dependent pedestals and secreting cholera-like toxin 

c. Listeria is a food-borne organism that establishes an intracellular infection in the GI tract, but can become systemic and cause meningitis 

d. Clostridium difficile causes inflammation of colonic mucosa after antibiotic treatment, and secretes toxins that target small GTPases, leading to disruption of epithelial tight junctions 

e. the predominant enterohaemorrhagic Escherichia coli (EHEC) serotype O157 is transmitted from beef, and in addition to inflammatory disease it produces a ADP-ribosylating toxin that can cause renal failure

Answer 143

A - T

B - F; colonises via fimbrial (pili) adhesins and then cholera-like enterotoxin (LT). EPEC delivers Tir as does EHEC

C - T

D - T; glucosylate small GTPases thereby disrupting actin cytoskeleton and tight junctions

E - F; it does cause renal failure but shiga toxin (assuming similar to shiga like is a glycosidase that depurinates 28S rRNA rather than ADP-ribosylating)

Question 144

Regarding toxinogenic bacteria 

a. pneumolysin, streptolysin O, Helicobacter VacA and Clostridium perfringens alpha-toxin all form pores in host cell membranes 

b. uropathogenic Escherichia coli (UPEC) bind kidney cells via adhesins on the tip of P-pili and produce cytotoxic necrotizing factor, a deamidase that targets host cell GTPases 

c. staphylococcal toxic shock syndrome toxin (TSST) is a superantigen that stimulates a cytokine storm after binding major histocompatibility complex (MHC) class I and T cell receptor molecules 

d. shiga toxin is a glycosidase that modifies small GTPases, inhibiting protein synthesis 

e. Corynebacterium ulcerans and Corynebacterium diphtheriae cause respiratory disease in which an ADP-ribosylating toxin targets host translation

Answer 144

A - F; clostridium perfrigens alpha toxin apparenty degrades the membrane but is not in the list of pore forming toxins

B - T

C - F

D - F

E - T; related to the pathogen C. pseudotuberculosis

Question 145

The following statements are true 

A. Salmonella enterica and Salmonella typhi cause zoonotic gastrointestinal disease in humans 

B. Neisseria generates antigenic variation of surface pili by recombining silent pilin genes into active expression loci 

C. Chlamydia trachomatis causes trachoma and urethritis, and is an obligate intracellular pathogen 

D. both streptococcal glomerulonephritis and arthropod-borne Lyme’s disease caused by Borrelia involve type III hypersensitivity 

E. cholera toxin, pertussis toxin and diphtheria toxin are multimeric

Answer 145

The following statements are true 

A. Salmonella enterica and Salmonella typhi cause zoonotic gastrointestinal disease in humans (FALSE)

B. Neisseria generates antigenic variation of surface pili by recombining silent pilin genes into active expression loci (TRUE)

C. Chlamydia trachomatis causes trachoma and urethritis, and is an obligate intracellular pathogen (TRUE)

D. both streptococcal glomerulonephritis and arthropod-borne Lyme’s disease caused by Borrelia involve type III hypersensitivity (TRUE)

E. cholera toxin, pertussis toxin and diphtheria toxin are multimeric (FALSE)

Question 146

In fungal infections 

a. a dimorphic fungus exists as a mould at 37°C and as a yeast at 24°C 

b. Cryptococcus is a yeast 

c. asymptomatic persistent Aspergillus infection of alveolar macrophages is common 

d. Sporothrix infection is acquired by inhalation 

e. the azole anti-fungal Fluconazole inhibits the synthesis of cholesterol

Answer 146

A - F; e.g. histoplasma --> when warm they are yeasts

B - T 

C - F; it occurs in those with lung cavities, asthma, or severe deficiencies in neutrophils and it has a very high fatality

D - F; you get it from cuts e.g. rose picker's disease

E - F; ergosterol

Question 147

In fungal infections 

a. CD4+ T cells are essential for host defence against systemic (deep) yeast infections 

b. superficial fungal infections of the skin are often transmitted indirectly by spores on inanimate surfaces 

c. the echinocandin anti-fungal Caspofungin inhibits the synthesis of β-glucan 

d. Th17 cells are essential for host defence against superficial fungal infections 

e. the polyene anti-fungal Amphotericin damages the fungal cell membrane

Answer 147

A - T; CD4+ --> Th17 --> IL-17 and IL-22

B - T; e.g. dermatophyte moulds such as microsporum, trichopyton and epidermophyton 

C - T

D - T

E - T

Question 148

Regarding helminths 

a. dogs are a definitive host for Echinococcus tapeworms 

b. Schistosoma japonicum infection is associated with bladder cancer 

c. Trichuris trichuria infection can last for decades 

d. Enterobius vermicularis infections are rare in the UK 

e. Taenia solium causes neurocysticercosis

Answer 148

A - T

B - T; not sure if this one is true because we learn about S. Mansoni but hopefully

C - T; e.g. whipworm

D - F; most common worm infection, especially in young children

E - T; epilepsy, seizures and blindness

Question 149

Regarding schistosomiasis

a. the adult worm protects against immune attack by secreting proteases that cleave iC3b 

b. granulomas are characteristic of the immune response to schistosome adult worms 

c. Albendazole is the drug of choice for treatment 

d. resistance to Schistosoma mansoni re-infection is highest in adolescent children 

e. severe fibrosis is associated with a sustained Th2 cell response

Answer 149

A - T; apparently m28 protein cleaves

B - T; Th2

C - F; praziquantal

D - F? not really sure on this

E - T

Question 150

Regarding tapeworms 

a. the scolex maintains the adult tapeworm position in the gut 

b. adults are hermaphrodites 

c. hydatid cysts are a major cause of epilepsy 

d. the proglottid is a male reproductive unit 

e. Echinococcus granulosus causes alveolar disease that can result in jaundice

Answer 150

A - T

B - T

C - T; cystercerci can cause epilepsy

D - F; they are eggs --> think there's not really sexes 

E - F; alveolar disease isn't gonna cause jaundice

Question 151

Regarding Apicomplexa 

A. micronemes, apicoplasts, and rhoptries are all secretory organelles of the apical complex 

B. bradyzoites and sporozoites are the dividing forms of Toxoplasma gondii in intermediate hosts 

C. the phylum includes Eimeria, Babesia and Theileria species 

D. Plasmodium falciparum CpG DNA and haemazoin are recognised by TLR9 

E. during invasion Plasmodium vivax merozoites bind to the human Duffy antigen receptor for chemokines

Answer 151

A - F; apical complex = microneme, rhoptry and dense granule

B - F; bradyzoites are normally quiescent tissue cysts while the oocysts are formed by the gametocytes that fuse to form an oocyst. Also the cat is the definitive host and this is where the sexual cycle occurs.

C - T

D - F; CpG DNA will be be for TLR9 but I think the haemazoin will be TLR-2 or TLR1/6 --> see diagram

E - T

Question 152

Malaria in humans 

a. is most commonly caused by Plasmodium vivax and Plasmodium falciparum 

b. is a major cause of childhood fatality in sub-Saharan Africa 

c. includes cerebral malaria caused by red blood cell sequestration mediated by variable PfEMP adherence to the vascular endothelium 

d. has selected for changes in haemoglobin, some of which act to decrease red blood cell sequestration by reduced adherence to the vascular endothelium 

e. is a disease found only in sub-Saharan Africa

Answer 152

A - T; 40-50% for falciparum and 15-20% for vivax

B - T

C - T

D - F; PfEMPs that increase adherence via iCAM-1 to reduce clearance by the spleen

E - F

Question 153

Regarding control or treatment of parasitic infections 

a. the African Programme for Onchocerciasis Control provides mass Praziquantel administration 

b. Lumefantrine and Amodiaquine are used in artemisinin-based combination therapies 

c. the “Roll Back Malaria” initiative has a major emphasis on long-lasting insecticidal nets containing DDT and indoor residual spraying 

d. chloroquine in the first-line drug of choice for Plasmodium vivax 

e. since publication of the Millennium Development Goals, the death rates amongst under 5 year olds from malaria has decreased by 65%

Answer 153

A - F; Ivermectin acn be used against a range: worm parasites --> arthropod ectoparasites

B - T

C - F; nets contains pyrethroid insecticides while indoor residual spraying uses DDT

D - T; also P. ovale

E - T

Question 154

A brain infarct 

A. may be a complication of coronary artery thrombosis 

B. may produce a cyst 

C. usually heals by regeneration 

D. is characterised by caseation necrosis 

E. may be due to atherosclerosis in a common carotid artery

Answer 154

A brain infarct 

A. may be a complication of coronary artery thrombosis (FALSE)

B. may produce a cyst (TRUE)

C. usually heals by regeneration (FALSE)

D. is characterised by caseation necrosis (FALSE)

E. may be due to atherosclerosis in a common carotid artery (TRUE)

Question 155

A thrombus in the left ventricle may 

A. heal by organisation 

B. embolise to the lungs 

C. cause a cerebral infarct 

D. become infected 

E. be due to an aneurysm

Answer 155

A thrombus in the left ventricle may 

A. heal by organisation (TRUE)

B. embolise to the lungs (FALSE)

C. cause a cerebral infarct (TRUE)

D. become infected (TRUE)

E. be due to an aneurysm (TRUE)

Question 156

In dyserythropoiesis: 

a. normal folate stores last for five years 

b. disease of the small bowel may lead to iron deficiency 

c. folate deficiency may lead to iron deposition in the liver 

d. iron deficiency causes macrocytosis 

e. folate deficiency is exacerbated by pregnancy

Answer 156

A - F; vit B12

B - T; e.g. coeliac

C - T; in both B12 and folate deficiency iron cannot be utilised normally and so is deposited in various organs

D - F; microcytosis

E - T

Question 157

The following are pro-thrombotic 

A. microparticles 

B. prostacyclin 

C. protein C 

D. thrombomodulin 

E. thromboplastin

Answer 157

The following are pro-thrombotic 

A. microparticles (TRUE)

B. prostacyclin (FALSE)

C. protein C (FALSE)

D. thrombomodulin (FALSE)

E. thromboplastin (TRUE)

Question 158

Atheromatous plaques 

A. can affect the media of blood vessels 

B. are more likely to occur if levels of blood triglycerides are elevated 

C. may be calcified 

D. are more likely to occur in individuals with diabetes mellitus 

E. only develop in arteries or veins

Answer 158

Atheromatous plaques 

A. can affect the media of blood vessels (FALSE)

B. are more likely to occur if levels of blood triglycerides are elevated (TRUE)

C. may be calcified (TRUE)

D. are more likely to occur in individuals with diabetes mellitus (TRUE)

E. only develop in arteries or veins (FALSE)

Question 159

A malignant growth 

A. can form metastases 

B. is contained in a capsule 

C. invades surrounding tissue 

D. can be called a leiomyoma 

E. is always caused by inherited genetic mutations

Answer 159

A malignant growth 

A. can form metastases (TRUE)

B. is contained in a capsule (FALSE)

C. invades surrounding tissue (TRUE)

D. can be called a leiomyoma (FALSE)

E. is always caused by inherited genetic mutations (FALSE)

Question 160

In cancers 

a. an adenoma is a malignant growth of colorectal tissue 

b. cervical cancer is a malignancy of squamous epithelium 

c. a neoplasm is always malignant 

d. leukaemia can derive from myeloid or lymphoid cells 

e. metaplasia describes the proliferation status of tumour cells

Answer 160

A - F

B - F; 90% are squamous but 10% are adenocarcinoma

C - F

D - T; liquid haemopoietic neoplasm e.g. CML and CLL

E - F; change from one differentiated cell type to another due to the presence of a stimulus

Question 161

Concerning mutations underlying cancer 

a. all mutations contribute to tumour growth 

b. the majority of mutations detected in cancer are in tumour suppressor genes 

c. activation of DNA damage repair genes is an important source of mutation 

d. genetic instability can be caused by defects in mismatch repair 

e. genetic instability is essential for the development of malignancies

Answer 161

A - F

B - F

C - F

D - T

E - F; can have growth control or genetic instability and they are separate mechanisms

Question 162

The hallmarks of cancer 

A. include independence of growth–stimulating signals 

B. include increased sensitivity to apoptosis 

C. can be induced by bcl2 translocations 

D. include block in cellular differentiation 

E. include angiogenesis

Answer 162

The hallmarks of cancer 

A. include independence of growth–stimulating signals (TRUE)

B. include increased sensitivity to apoptosis (FALSE)

C. can be induced by bcl2 translocations (TRUE)

D. include block in cellular differentiation (TRUE)

E. include angiogenesis (TRUE)

Question 163

Mutations associated with cancer include 

a. gain of function mutations in PTEN 

b. amplification of cyclin D1 

c. loss of function mutations in Rb1 

d. inactivating mutations of APC and β-catenin 

e. epigenetic modifications

Answer 163

A - F; loss of function as TS

B - T

C - T

D - F; activation of beta-catenin is pro-proliferative

E - T; 30-50% of colon cancers show epigenetic instability e.g. methylation of MLH1

Question 164

Drugs used to treat cancer 

a. can activate the immune system by inhibiting PD-1 

b. can function by inhibiting the ATP-binding pocket of phosphatases 

c. can induce DNA damage 

d. such as Vemurafenib, the BRAF inhibitor, activates growth of cells with RAS mutations 

e. such as platinum compounds, inhibit mitotic spindles

Answer 164

A - T; inhibit PD-1 thereby leading to increased T cell activation

B - F; I think if this was kinases then it might be true but PTEN is anti-cancer and is the only phoshatase mentioned

C - T; e.g. cis-platin

D - F

E - F; taxanes

Question 165

Concerning environmental agents and cancer 

A. ultraviolet (UV) light induces guanine dimers 

B. exposure to aflatoxins is associated with bladder cancer 

C. mutagens can be identified by the Ames test 

D. human T lymphotropic virus 1 (HTLV-1) is associated with Kaposi’s sarcoma 

E. causes of cancer can be identified by epidemiological studies

Answer 165

Concerning environmental agents and cancer 

A. ultraviolet (UV) light induces guanine dimers (FALSE)

B. exposure to aflatoxins is associated with bladder cancer (FALSE)

C. mutagens can be identified by the Ames test (TRUE)

D. human T lymphotropic virus 1 (HTLV-1) is associated with Kaposi’s sarcoma (FALSE)

E. causes of cancer can be identified by epidemiological studies (TRUE)

Question 166

Regarding the status of signalling pathways in cancer 

a. the mitogen-activated protein (MAP) kinase pathway is often inactivated 

b. activation of p53 can result in cell cycle arrest or apoptosis 

c. DNA damage increases p53 activity 

d. p53 is a negative regulator of mdm2 

e. mixed lineage leukemia (MLL) is associated with activation of a histone lysine acetyltransferase

Answer 166

A - F

B - T

C - T

D - F; MDM2 is a negative regulator of p53

E - F; MLL is a histone methyase that is fused to other genes in leukaemias that turns a gene on

Question 167

Concerning cancer therapy 

A. the Kaplan-Meier curve relates cancer incidence to radiation dose 

B. Glivec (a.k.a. Gleevec) targets K-RAS 

C. PARP inhibitors activate the immune response to cancers 

D. PD-1 and CTLA-4 are found on certain T cells 

E. platinum compounds such as cis-platin cross-link DNA strands

Answer 167

Concerning cancer therapy 

A. the Kaplan-Meier curve relates cancer incidence to radiation dose (FALSE)

B. Glivec (a.k.a. Gleevec) targets K-RAS (FALSE)

C. PARP inhibitors activate the immune response to cancers (FALSE)

D. PD-1 and CTLA-4 are found on certain T cells (TRUE)

E. platinum compounds such as cis-platin cross-link DNA strands (TRUE)

Question 168

The following agents are implicated in increasing the risk of the stated cancers 

a. hepatitis B virus and liver cancer 

b. napthylamine and bladder cancer 

c. aflatoxin and liver cancer 

d. Epstein-Barr Virus and Kaposi’s Sarcoma 

e. asbestos and breast cancer

Answer 168

A - T

B - T

C - T

D - F

E - F

Question 169

Concerning inherited predisposition to cancer 

a. the inherited mutation is usually loss-of-function and heterozygous 

b. in patients with hereditary predisposition to retinoblastoma, retinoblastomas are usually homozygous for loss of RB1 

c. mutations that cause inherited predisposition may either be in growth-control pathways or DNA-repair pathways 

d. breast cancer predisposition due to mutated BRCA1 or BRCA2 is among the most prevalent genetic diseases in the UK 

e. most patients with a strong hereditary predisposition to colon cancer inherit a defect in mismatch repair

Answer 169

A - T

B - T

C - T

D - T

E - T

Question 170

Malignant colorectal or colon tumours often 

a. arise from papillomas 

b. have truncation of K-RAS 

c. have mutation of both p53 (TP53) and APC 

d. have mutation of both B-RAF and K-RAS 

e. have chromosome rearrangements

Answer 170

A - F

B - F; K-ras is mutation in a range of cancers but is usually activated by point mutations that block hydrolysis

C - T

D - T; also in 60% of melanomas

E - T; not totally sure

Question 171

Examples of oncogene activation include 

a. point mutation of B-RAF 

b. promoter methylation of p16Ink4a (also known as p16 or CDKN2A) 

c. deletion of SMAD4 

d. fusion of B-RAF by tandem duplication 

e. amplification of HER2 (also known as ERBB2)

Answer 171

A - T

B - F; it is often deleted completely

C - T; it inhibits proliferation and survival and is downstream of the TGF beta pathway (e.g. tumour supressor gene)

D - T; to KIAA1549 in paediatric astrocytomas

E - T; 10-20% of breast cancers

Question 172

Concerning genetic instability in cancer 

A. microsatellite instability arises from defects in mitosis 

B. mismatch repair deficiency occurs in the majority of colon cancers 

C. activation of telomerase leads to genetic instability 

D. genetic instability is occasionally caused by mutations in DNA polymerases 

E. BRCA2-deficiency is associated with chromosome instability

Answer 172

Concerning genetic instability in cancer 

A. microsatellite instability arises from defects in mitosis (FALSE)

B. mismatch repair deficiency occurs in the majority of colon cancers (FALSE)

C. activation of telomerase leads to genetic instability (FALSE)

D. genetic instability is occasionally caused by mutations in DNA polymerases (TRUE)

E. BRCA2-deficiency is associated with chromosome instability (TRUE)

Question 173

Concerning neoplasia 

a. leiomyoma is a benign tumour arising from muscle 

b. an adenoma is a benign tumour of glandular epithelium 

c. adenocarcinoma of the cervix does not require metaplasia 

d. adenocarcinoma of the cervix is a benign neoplasm 

e. lipoma is a benign neoplasm

Answer 173

A - T

B - T

C - T

D - F

E - T

Question 174

The following distinguish malignant from benign neoplasms

a. ability to metastasize 

b. ability to kill a patient 

c. invasion of the surrounding normal tissue 

d. in the uterine cervix, papillomavirus infection 

e. presence of tumour suppressor mutations

Answer 174

A - T

B - F

C - T

D - F

E - F

Question 175

A lung infarct 

A. Usually heals by regeneration 

B. May be accompanied by pleurisy (pleuritis) 

C. May produce heart failure 

D. Typically appears pale after 24 hours 

E. Is at high risk of infection

Answer 175

A lung infarct 

A. Usually heals by regeneration (TRUE)

B. May be accompanied by pleurisy (pleuritis) (TRUE)

C. May produce heart failure (FALSE)

D. Typically appears pale after 24 hours (FALSE)

E. Is at high risk of infection (TRUE)

Question 176

Concerning anaemia 

A. folate deficiency is common in vegans 

B. B12 deficiency leads to macrocytosis 

C. iron deficiency can affect cytochrome function 

D. beta thalassaemia is characterised by both reduced production and increased destruction of red blood cells 

E. angina may worsen if anaemia develops

Answer 176

Concerning anaemia 

A. folate deficiency is common in vegans (FALSE)

B. B12 deficiency leads to macrocytosis (TRUE)

C. iron deficiency can affect cytochrome function (TRUE)

D. beta thalassaemia is characterised by both reduced production and increased destruction of red blood cells (TRUE)

E. angina may worsen if anaemia develops (TRUE)

Question 177

Atheromatous plaques 

A. can arise in arteries, veins or capillaries 

B. are more likely to occur if levels of blood high density lipoproteins are elevated 

C. may lead to embolism 

D. can cause aneurysms 

E. are more likely to occur in post-menopausal women than in pre-menopausal women

Answer 177

Atheromatous plaques 

A. can arise in arteries, veins or capillaries (FALSE)

B. are more likely to occur if levels of blood high density lipoproteins are elevated (FALSE)

C. may lead to embolism (TRUE)

D. can cause aneurysms (TRUE)

E. are more likely to occur in post-menopausal women than in pre-menopausal women (TRUE)

Question 178

Ischaemia 

A. may be a consequence of a myocardial infarct 

B. can cause coagulative necrosis 

C. is tolerated better by neurones than by myocardial cells 

D. can cause cell swelling 

E. leads to a low concentration of blood haemoglobin

Answer 178

Ischaemia 

A. may be a consequence of a myocardial infarct (FALSE)

B. can cause coagulative necrosis (TRUE)

C. is tolerated better by neurones than by myocardial cells (FALSE)

D. can cause cell swelling (TRUE)

E. leads to a low concentration of blood haemoglobin (FALSE)

Question 179

A thrombus in a leg vein may 

A. be a complication of hypertension 

B. embolize to the kidney 

C. be due to inherited deficiency of protein C 

D. be associated with Factor VIII deficiency 

E. become infected

Answer 179

A thrombus in a leg vein may 

A. be a complication of hypertension (FALSE)

B. embolize to the kidney (FALSE)

C. be due to inherited deficiency of protein C (TRUE)

D. be associated with Factor VIII deficiency (FALSE)

E. become infected (TRUE)

Question 180

Concerning eukaryotic parasites and the human host 

A. humans are the definitive hosts of Plasmodium vivax 

B. microfilaria are micro-parasites capable of multiplying within human host 

C. humans can be both the intermediate and definitive host of Taenia solium 

D. vertical transmission of Toxoplasma gondii can occur in humans 

E. prevalence rather than intensity of helminth infection is strongly associated with severe human morbidity

Answer 180

Concerning eukaryotic parasites and the human host 

A. humans are the definitive hosts of Plasmodium vivax (FALSE) 

B. microfilaria are micro-parasites capable of multiplying within human host (FALSE)

C. humans can be both the intermediate and definitive host of Taenia solium (FALSE)

D. vertical transmission of Toxoplasma gondii can occur in humans (TRUE)

E. prevalence rather than intensity of helminth infection is strongly associated with severe human morbidity (FALSE)

Question 181

Schistosoma haematobium can cause the following 

A. haematuria 

B. Symmers clay pipestem fibrosis 

C. hydronephrosis 

D. bladder transitional cell carcinoma 

E. Katayama Fever

Answer 181

A - T

B - F

C - F

D - T

E - T

Question 182

Concerning Plasmodium falciparum 

a. PfEMP-1 is encoded by at least 50 var genes 

b. liver schizonts rupture to release up to 30,000 hypnozoites 

c. prophylactic chemotherapy is important for disease control in endemic countries 

d. in placental malaria PfEMP-1 binds chondroitin sulphate A 

e. individuals lacking the Duffy blood group antigen are resistant to infection

Answer 182

A - T; around 60

B - F; they release around 10,000 merozoites in a schizont

C - T

D - T

D - F

Question 183

The following are stages within insects during the Plasmodium life cycle 

A, Ookinete 

B. Amastigote 

C. Sporozoite 

D. Sporocyst 

E. Kinetoplast

Answer 183

The following are stages within insects during the Plasmodium life cycle 

A. Ookinete (TRUE)

B. Amastigote (FALSE)

C. Sporozoite (TRUE)

D. Sporocyst (TRUE)

E. Kinetoplast (FALSE)

Question 184

The following are transmitted by vectors 

A. Necator americanis (hookworm) 

B. Wucheria bancrofti (Elephantiasis) 

C. Trypanosoma cruzi (Chagas’ disease) 

D. Plasmodium ovale (Malaria) 

E. Taenia saginata (beef tapeworm)

Answer 184

The following are transmitted by vectors 

A. Necator americanis (hookworm) (FALSE)

B. Wucheria bancrofti (Elephantiasis) (FALSE)

C. Trypanosoma cruzi (Chagas’ disease) (TRUE)

D. Plasmodium ovale (Malaria) (TRUE)

E. Taenia saginata (beef tapeworm) (FALSE)

Question 185

The following are neglected tropical diseases caused by protozoan parasites 

a. Dracunculiasis 

b. Echinococcosis 

c. Malaria 

d. Chagas’ disease 

e. Onchocerciasis

Answer 185

A - F; worm

B - F; not tropical

C - F; not neglected

D - T

E - F; worm

Question 186

Regarding antibiotics 

A. resistance to trimethoprim, the inhibitor of folate synthesis, is conferred by a ‘bypass’ dihydrofolate reductase 

B. tetracycline binds the 30S ribosomal subunit, inhibiting the peptidyl transferase 

C. chloramphenicol binds the large ribosomal subunit and blocks host cell translation, but resistance follows antibiotic modification by an acetyl transferase 

D. fluoroquinolones like ciprofloxacin inhibit gyrase and block transcription 

E. vancomycin mimics D-Ala-D-Ala crosslinks to prevent peptidoglycan crosslinking, but variant transpeptidases make vancomycin-resistant peptide crosslinks

Answer 186

Regarding antibiotics 

A. resistance to trimethoprim, the inhibitor of folate synthesis, is conferred by a ‘bypass’ dihydrofolate reductase (TRUE)

B. tetracycline binds the 30S ribosomal subunit, inhibiting the peptidyl transferase (FALSE)

C. chloramphenicol binds the large ribosomal subunit and blocks host cell translation, but resistance follows antibiotic modification by an acetyl transferase (FALSE)

D. fluoroquinolones like ciprofloxacin inhibit gyrase and block transcription (TRUE)

E. vancomycin mimics D-Ala-D-Ala crosslinks to prevent peptidoglycan crosslinking, but variant transpeptidases make vancomycin-resistant peptide crosslinks (FALSE)

Question 187

In host defence against bacteria 

a. IFN and NK cells are usually the most important components b. neutralizing antibodies block cell adhesion and also toxin action 

c. lysozyme breaks down bacterial surface capsular polysaccharide 

d. TLR5 recognizes flagellin 

e. the commensal flora of the gut comprises only obligate anaerobic bacteria

Answer 187

A - F

B - F

C - F; peptidoglycan

D - T

E - F

Question 188

Uropathogenic E.coli 

a. are typically commensals of the lower urinary tract, causing ascending infection to the bladder (causing cystitis) and kidney (causing pyelonephritis) 

b. colonize the kidney using adhesins on the tip of P-pili, binding receptors on kidney epithelial cells 

c. P pili are assembled from subunits incorporated by the chaperone-usher pathway 

d. kidney damage is largely caused directly by a bacterial pore-forming toxin and indirectly by the inflammatory response 

e. commonly cause kidney stones if infection recurs and inflammation persists

Answer 188

A - F

B - T

C - T

D - T; haemolysin for pore and LPS for inflammation

E - F; proteus

Question 189

The following typically cause outbreaks of human disease after ingestion of contaminated meat or dairy products 

A. Legionella pneumophila 

B. Enterohemorrhagic E.coli (EHEC) 

C. Salmonella enterica 

D. Staphylococcus aureus 

E. Vibrio cholera

Answer 189

The following typically cause outbreaks of human disease after ingestion of contaminated meat or dairy products 

A. Legionella pneumophila (FALSE)

B. Enterohemorrhagic E.coli (EHEC) (TRUE)

C. Salmonella enterica (TRUE)

D. Staphylococcus aureus (TRUE)

E. Vibrio cholera (FALSE)

Question 190

In gastrointestinal infections 

a. Helicobacter pylori is a motile Gram-negative bacterium for which VacA is a key virulence factor in causing gastric ulceration b. ETEC, which cause traveller’s diarrhoea, colonizes host cells by a fimbrial adhesin and secretes an ADP-ribosylating toxin 

c. Listeria invades intestinal cells by receptor-mediated endocytosis to establish an intracellular infection, but it can become systemic and cross the bloodbrain barrier 

d. Clostridium difficile causes inflammation of the colonic mucosa and secretes toxins that disrupt the actin cytoskeleton and epithelial tight junctions 

e. circulating Shiga toxin secreted by Shigella inhibits Rho/Ras GTPases, disrupting the cellular cytoskeleton and causing kidney damage

Answer 190

A - T

B - T

C - T

D - T

E - F; glycosidaase that depurinates 28S rRNA --> shiga like toxin of EHEC does cause kidney failure though

Question 191

In respiratory infections 

a. diphtheria toxin is an ADP-ribosylating enzyme that modifies host ribosomal RNA and blocks translation 

b. chronic granulomatous disease caused by M. tuberculosis is typically resolved by a TH2 response 

c. pharyngitis is caused by the Gram-positive bacterium Streptococcus pyogenes, which is Lancefield group A based on cell surface carbohydrate 

d. Mycobacteria do not Gram stain, but are visible after Ziehl-Neelsen staining of polyphosphate granules in the cytosol 

e. immunity to M. tuberculosis is detected as a T cell response by the tuberculin skin test, and conferred by the live BCG vaccine

Answer 191

A - F

B - F

C - T

D - F

E - T

Question 192

In pathogenic bacteria 

a. growth typically involves haploid chromosome replication and binary fission to generate two identical progeny cells 

b. Salmonella enterica has c.5-6000 genes, with many that are involved in disease located on SPI-1 and SPI-2 pathogenicity islands 

c. endotoxin is the lipid A component of bacterial LPS, and activates macrophages via CD14 

d. transformation involves DNA uptake following contact between two bacterial cells 

e. Chlamydia have less than 200 genes and consequently are obligate intracellular parasites

Answer 192

A - T

B - F

C - T

D - F

E - F

Question 193

These are obligate anaerobes that produce endospores 

A. Staphylococcus aureus 

B. Clostridium perfringens 

C. Bacteriodes fragilis 

D. Streptococcus viridans 

E. Clostridium tetani

Answer 193

These are obligate anaerobes that produce endospores 

A. Staphylococcus aureus (FALSE)

B. Clostridium perfringens (TRUE)

C. Bacteriodes fragilis (FALSE)

D. Streptococcus viridans (FALSE)

E. Clostridium tetani (TRUE)

Question 194

Regarding bacterial toxins 

A. pneumolysin, streptolysin O, staphylococcal alpha-toxin and E. coli hemolysin all form pores in host cell membranes 

B. tetanus toxin is a protease that cleaves synaptobrevin, blocking release of inhibitory neurotransmitters in the CNS 

C. Bordetella pertussis produces toxins that, respectively, subvert adenylate cyclase regulation and mimic activity of the mammalian enzyme 

D. membrane-damaging Clostridium perfringens alpha-toxin is a phospholipase detected on egg yolk agar (the Nagler test) 

E. the DPT vaccine comprises toxoid preparations of diphtheria, pertussis and tetanus toxins

Answer 194

A - T

B - T

C - T

D - T

E - F; killed pertussis and then toxoid D and T

Question 195

Fungal infections 

a. can be detected by recognition of fungal cell wall polysaccharides by lectins on the surface of neutrophils 

b. activate the complement enzyme cascade through DC-SIGN recognition of mannose-rich structures 

c. can be diagnosed by examining morphology using a microscope 

d. by Histoplasma capsulatum can lead to granuloma formation e. by Pneumocystis jirovecii is associated with airway colonization in asthma suffers

Answer 195

A - T; lectins are PRRs that can be in the plasma or on the surface of DCs, macrophages, neutrophils, some epithelial

B - F; MBL but if on surfacethen you get a cascade that leads to production of CD4+ T cells and IL-17 and IL-22

C - T

D - T

E - F; HIV

Question 196

Regarding fungi 

a. dimorphic fungi such as Histoplasma capsulatum primarily adopt a filamentous mould morphology in the body of a mammal b. filamentous moulds can form a mycelium (an interwoven mass of hyphae) 

c. the yeast Schizosaccharomyces pombe undergoes mitosis by asymmetrical budding 

d. Candida albicans is present as part of the normal flora on human mucous membranes 

e. spores are fungal cells that are adapted to survival in a hostile environment

Answer 196

A - F

B - T; hyphae can form an interwoven mass called a mycelium

C - F; symmetrical budding

D - T; in the throat, gut and vagina

E - T

Question 197

Smallpox 

A. was caused by vaccinia virus 

B. presented with skin pustules evenly spread over the body, similar to chickenpox 

C. was eradicated using a virus vaccine that was inactivated by freeze-drying 

D. was only a disease of humans with no animal reservoir 

E. vaccine induces both cellular and humoral immunity

Answer 197

A - F

B - F; centrifugal pattern

C - T

D - T

E - T

Question 198

In a multicellular host with a competent immune system 

a. pattern recognition receptors (PRRs) can recognise virus pathogen associated molecular patterns (PAMPs) in the cytoplasm or in endosomes 

b. different cell types produce different types of interferon molecules in response to infection 

c. cytotoxic T lymphocytes efficiently recognise and destroy free virus particles 

d. viruses directly inhibit the action of complement by down-regulating MHC class I molecules 

e. the interferon-stimulated gene product protein kinase R (PKR) requires activation by viral double-stranded RNA

Answer 198

A - T; RIG for viral RNA in cytoplasm and then TLR

B - T; IFN alpha and beta produced by infected cell, IFN gamma relased by activated T cells and macrophages, IFNdeltas produced by epithelial cells

C - F

D - F

E - T

Question 199

Histopathological features associated with virus infection include 

a. nuclear inclusion bodies caused by molluscum contagiosum (a poxvirus) 

b. cytoplasmic inclusion bodies termed Negri bodies in poliovirus infected Purkinje cells 

c. syncytia (fused cells) caused by varicella-zoster virus infection d. mitotic figures in cells adjacent to sites of vaccinia virus infection 

e. owl-eye inclusion bodies in cytomegalovirus infected cells

Answer 199

A - F; cytoplasmic inclusions

B - F; rabies

C - F; measles

D - T; epidermal growth factor to stimulate division of neighbouring cells

E - T

Question 200

Regarding virus infections of the liver 

A. hepatitis B virus replication requires reverse transcription 

B. chronic infection by hepatitis C virus is rare in people infected after 5 years of age 

C. hepatitis A virus is a non-enveloped positive strand RNA virus 

D. hepatitis B virus causes acute infection and jaundice 

E. translation of the hepatitis C virus polyprotein is controlled by an internal ribosome entry site (IRES)

Answer 200

A - T

B - F

C - T

D - T

E - F; think this is just poliovirus

Question 201

Ebola virus 

a. is a member of the Rhabdoviridae family 

b. must package its viral RNA-dependent RNA polymerase in the virion to be infectious 

c. inhibits interferon response factor 3 (IRF3) activation via the VP35 protein 

d. is efficiently transmitted by the aerosol route 

e. infects macrophages

Answer 201

A - F; filovirus

B - T; it is negative sense 

C - T

D - F; body fluid e.g. blood and secretions

E - F; yellow fever + ectromelia virus + HIV can grow in macrophages + hep A can infect liver macrophages

Question 202

Influenza A virus 

a. infections can be treated with relenza, a neuraminidase inhibitor 

b. has natural reservoirs in horses, pigs and birds 

c. undergoes antigenic shift due to the gradual accumulation of mutations in the HA gene 

d. contains 7 RNA segments 

e. gains entry to the cell by binding to the cellular CCR5 receptor

Answer 202

A - T

B - T

C - F

D - F

E - F

Question 203

Regarding the production of viral mRNA and protein 

a. retroviruses do not produce spliced transcripts 

b. many vaccinia virus proteins are expressed from spliced transcripts 

c. HIV mRNA transcription is mediated by a viral DNA dependent RNA polymerase 

d. some retrovirus proteins are proteolytically processed 

e. poliovirus encodes a polyprotein that is post-translationally cleaved

Answer 203

A - F

B - F; I think --> made it easier to map and eradicate potentially?

C - F; host DNA-dependent RNA pol II

D - T; 

E - T

Question 204

When quantifying viral loads 

A. plaque assays are a method to measure the number of infectious virus particles in samples 

B. plaque assays can be used for all viruses 

C. counting virions generally requires use of an electron microscope 

D. ten plaque-forming units (pfu) of influenza virus is approximately equivalent to one million haemagglutination (HA) units 

E. the polymerase chain reaction (PCR) is a rapid and sensitive method used to quantify the number of infectious particles in a sample

Answer 204

A - T

B - F; not hep B

C - T

D - F

E - T

Question 205

Viruses that are known to cause latent infections include 

A. influenza virus 

B. rotavirus 

C. varicella-zoster virus 

E. Epstein Barr virus 

E. variola virus

Answer 205

Viruses that are known to cause latent infections include 

A. influenza virus (FALSE)

B. rotavirus (FALSE)

C. varicella-zoster virus (TRUE)

E. Epstein Barr virus (TRUE)

E. variola virus (FALSE)

Question 206

Pattern (or pathogen) recognition receptors (PRRs) 

A. rapidly evolve to allow detection of pathogen-associated molecular patterns (PAMPs) 

B. include RIG-I-like receptors (RLRs) that recognize foreign DNA 

C. of the TLR family often signal through NFκB and IRF3 

D. can recognize self-molecules produced by stress 

E. can respond to necrosis

Answer 206

Pattern (or pathogen) recognition receptors (PRRs) 

A. rapidly evolve to allow detection of pathogen-associated molecular patterns (PAMPs) (FALSE)

B. include RIG-I-like receptors (RLRs) that recognize foreign DNA (FALSE)

C. of the TLR family often signal through NFκB and IRF3 (TRUE)

D. can recognize self-molecules produced by stress (TRUE)

E. can respond to necrosis (TRUE)

Question 207

Natural Killer (NK) cells 

A. can respond to cells infected with bacteria 

B. can respond to the lack of MHC molecules on the cell surface 

C. are derived from a common myeloid progenitor 

D. can produce perforin and granzymes to kill cells 

E. can phagocytose infected cells

Answer 207

Natural Killer (NK) cells 

A. can respond to cells infected with bacteria (TRUE)

B. can respond to the lack of MHC molecules on the cell surface (TRUE)

C. are derived from a common myeloid progenitor (FALSE)

D. can produce perforin and granzymes to kill cells (TRUE)

E. can phagocytose infected cells (FALSE)

Question 208

Endothelial cell damage near a site of inflammation leads to 

A. activation of the kinin cascade that causes pain and vasodilation 

B. activation of the clotting cascade that helps contain an infection 

C. activation of the fibrin cascade that helps activate complement 

D. the recruitment of neutrophils 

E. prostaglandin production that promote vasodilation and vascular permeability

Answer 208

Endothelial cell damage near a site of inflammation leads to 

A. activation of the kinin cascade that causes pain and vasodilation (TRUE)

B. activation of the clotting cascade that helps contain an infection (TRUE)

C. activation of the fibrin cascade that helps activate complement (TRUE)

D. the recruitment of neutrophils (TRUE)

E. prostaglandin production that promote vasodilation and vascular permeability (TRUE)

Question 209

The large complement fragments C3b, C4b and C5b 

A. all have thioester bonds that link these fragments to the membrane 

B. are all related to the acute phase protein α2-macroglobulin 

C. are all opsonins that promote phagocytosis 

D. are all produced in the alternative pathway 

E. all bind C6 and C7 leading to the membrane attack complex (MAC)

Answer 209

The large complement fragments C3b, C4b and C5b 

A. all have thioester bonds that link these fragments to the membrane (FALSE)

B. are all related to the acute phase protein α2-macroglobulin (FALSE)

C. are all opsonins that promote phagocytosis (TRUE)

D. are all produced in the alternative pathway (FASLE)

E. all bind C6 and C7 leading to the membrane attack complex (MAC) (FALSE)

Question 210

Apoptosis 

A. is also known as programmed cell death 

B. happens only during disease 

C. involves caspases and Bcl-2 proteins 

D. can be activated by the inflammasome 

E. can be initiated by cytokines

Answer 210

Apoptosis 

A. is also known as programmed cell death (TRUE)

B. happens only during disease (FALSE)

C. involves caspases and Bcl-2 proteins (TRUE)

D. can be activated by the inflammasome (FALSE)

E. can be initiated by cytokines (TRUE)

Question 211

In lymphocyte development 

A. central tolerance is not important for controlling autoreactive B cells 

B. all potentially autoreactive T cells are prevented from leaving the thymus 

C. allelic exclusion refers to the selection of T cells that can only see particular alleles of MHC class I or class II 

D. VDJ recombination in T cells is guided by nonamer and heptamer DNA sequence elements 

E. defects in the autoimmune regulator (AIRE) results in the systemic autoimmune condition IPEX syndrome (Immune dysfunction, Polyendocrinopathy, Entropathy X-linked syndrome)

Answer 211

"

In lymphocyte development 

A. central tolerance is not important for controlling autoreactive B cells (FALSE)

B. all potentially autoreactive T cells are prevented from leaving the thymus (TRUE)

C. allelic exclusion refers to the selection of T cells that can only see particular alleles of MHC class I or class II (FASLE)

D. VDJ recombination in T cells is guided by nonamer and heptamer DNA sequence elements (TRUE)

E. defects in the autoimmune regulator (AIRE) results in the systemic autoimmune condition IPEX syndrome (Immune dysfunction, Polyendocrinopathy, Entropathy X-linked syndrome) (FALSE)

A - F; should require B cell help but not perfect so autoreactive B cells are elmininated as they develop

C - F; heavy chain rearrangement can occur on both chromosomes but if a functional heavy chain is generated then rearrangement on the other chromosome is prevented (allelic exclusion) 

E - F; IPEX = FOX, AIRE = APECED

"

Question 212

Major cytokines involved in suppressing TH1 responses include 

A. IL-4 

B. IL-12 

C. IL-10 

D. IFN-γ 

E. TNF-α

Answer 212

Major cytokines involved in suppressing TH1 responses include 

A. IL-4 (TRUE)

B. IL-12 (FALSE)

C. IL-10 (TRUE)

D. IFN-γ (FALSE)

E. TNF-α (FALSE)

Question 213

In considering transplantation 

a. allogeneic transplantation refers to transplants between individuals of the same species 

b. HLA matching is very important in survival of hematopoietic stem cell transplants 

c. corneal transplants are maintained in the absence of immunosuppression 

d. the graft-versus-host reaction is useful in the treatment of leukaemic patients 

e. autologous tissue transplants require immunosuppression

Answer 213

A - T

B - T

C - T

D - F; GvL not GvH

E - F

Question 214

Haemolytic disease of the newborn 

a. results in destruction of the foetal red blood cells by complement-mediated lysis 

b. is treated by administration of anti-rhesus antibody (RhoGam) which probably works by preventing activation of naïve (FcγRIIB +ve) Rhesus D-reactive Bcells 

c. is due to transport of anti-rhesus D IgM antibodies into the foetal circulation 

d. results in extensive destruction of foetal red blood cells in a first pregnancy 

e. is a major consideration when matching donor and recipients for blood transfusion for women

Answer 214

A - F; ADCC

B - T

C - F

D - F

E - T

Question 215

The following statements are true 

A. TH2 cells generally promote immune responses against helminth infections 

B. TH1 cells are considered pro-inflammatory 

C. FoxP3 (or Fox3p) is a transcription factor that drives production of TH1 cells 

D. the main role of TH17 cells is to promote macrophage recruitment to sites of infection 

E. a characteristic feature of CD25⁺ Tregs is that they express the CD8 coreceptor

Answer 215

The following statements are true 

A. TH2 cells generally promote immune responses against helminth infections (TRUE)

B. TH1 cells are considered pro-inflammatory (TRUE)

C. FoxP3 (or Fox3p) is a transcription factor that drives production of TH1 cells (FALSE)

D. the main role of TH17 cells is to promote macrophage recruitment to sites of infection (FALSE)

E. a characteristic feature of CD25+ve Tregs is that they express the CD8 coreceptor (FALSE)

Question 216

During T cell development 

a. medullary epithelial cells mediate the process of positive selection 

b. the majority of thymocytes die by neglect due to an inability to recognize self MHC with sufficient affinity 

c. thymocytes undergo T cell receptor rearrangement in the bone marrow and positive and negative selection in the thymus. 

d. the TCR alpha chain rearranges before the TCR beta chain 

e. in humans double-positive T cells that express both CD4 and CD8 are usually only found in the thymus

Answer 216

A - F

B - T

C - F

D - F

E - T

Question 217

Regarding MHC molecules 

a. HLA-A, HLA-B and HLA-C are regarded as alleles of each other 

b. the MHC class I binding groove generally accommodates peptides of 8-9 amino acids in length 

c. each MHC allele can potentially bind millions of different peptides 

d. T cells must see thousands of the same peptide/MHC complex if they are to become activated 

e. MHC polymorphism allows one individual to express hundreds of different MHC class I molecules

Answer 217

A - F

B - T

C - T

D - F

E - F

Question 218

Regarding autoimmune disease(s) 

A. IgE antibodies are rarely, if ever, involved directly in human autoimmune disease 

B. C1, C2 or C4 complement deficiency is a predisposing factor in systemic lupus erythematosus 

C. in the EAE rat model of multiple sclerosis, disease is associated with myelin basic protein specific TH1 CD4 T cells 

D. most autoimmune conditions are associated with specific mutant MHC alleles 

E. type IV autoimmune conditions are T cell-mediated

Answer 218

A - T

B - T

C - T

D - F

E -  T

Question 219

Regarding lymphocyte receptor generation 

a. the B cell receptor shows less junctional diversity than the T cell receptor 

b. rearranged TCR alpha chains are expressed at the cell surface with a surrogate beta chain 

c. complementary determining region 3 (CDR3) is more variable than CDR1 or CDR2 

d. activation induced (cytidine) deaminase is involved in generating point mutations during somatic hypermutation 

e. in immunoglobulin light chain rearrangement RAG recombinases recognize switch regions associated with the variable and junctional gene segments

Answer 219

A - T

B - F

C - T

D -T

E - T

Question 220

In ABO blood grouping 

A. individuals with blood group O are universal recipients 

B. individuals with blood group B will produce anti-A serum antibodies 

C. individuals with blood group B have a terminal galactose added to the core H antigen 

D. individuals with blood group AB are rare in the UK 

E. blood transfusion incompatibility is an example of type II hypersensitivity

Answer 220

A - F

B - T

C - T

D - T

E - T

Question 221

In an immune response 

A. natural antibody is mainly of the IgM isotype 

B. alternatively activated macrophages are highly pro-inflammatory 

C. phagocytosis is a major innate response to infection by protozoa 

D. helminths typically induce TH2-type responses 

E. TH17 cells stimulate neutrophil recruitment

Answer 221

In an immune response 

A. natural antibody is mainly of the IgM isotype (FALSE)

B. alternatively activated macrophages are highly pro-inflammatory (FALSE)

C. phagocytosis is a major innate response to infection by protozoa (TRUE)

D. helminths typically induce TH2-type responses (TRUE)

E. TH17 cells stimulate neutrophil recruitment (TRUE)

Question 222

Regarding antigen presentation

A. Professional antigen presenting cells include macrophages, dendritic cells and B-cells

B. Co-stimulatory molecule expression is a defining feature of professional antigen presenting cells

C. Foreign antigen presented by B lymphocytes is mainly taken up by phagocytosis

D. Peptide anchor residues interact with pockets in the MHC peptide binding groove

E. The proteasome generates the majority of peptides presented by MHC class II molecules

Answer 222

Regarding antigen presentation

A. Professional antigen presenting cells include macrophages, dendritic cells and B-cells (TRUE)

B. Co-stimulatory molecule expression is a defining feature of professional antigen presenting cells (TRUE)

C. Foreign antigen presented by B lymphocytes is mainly taken up by phagocytosis (FALSE)

D. Peptide anchor residues interact with pockets in the MHC peptide binding groove (TRUE)

E. The proteasome generates the majority of peptides presented by MHC class II molecules (FALSE)

Question 223

MHC class I molecules

A. are highly polymorphic

B. are expressed only on professional antigen-presenting cells

C. associate preferentially with pathogen-derived peptides

D. accommodate peptides in an open-ended peptide-binding groove

E. associate with β2 microglobulin

Answer 223

MHC class I molecules

A. are highly polymorphic (TRUE)

B. are expressed only on professional antigen-presenting cells (FALSE)

C. associate preferentially with pathogen-derived peptides (FALSE)

D. accommodate peptides in an open-ended peptide-binding groove (FALSE)

E. associate with β2 microglobulin (TRUE)

Question 224

Pathogen associated molecular patterns (PAMPs)

A. are highly conserved in evolution across species

B. are present in vertebrate hosts

C. are specific to the individual organism

D. can recognise double stranded RNA

E. include lipopolysaccharide

Answer 224

Pathogen associated molecular patterns (PAMPs)

A. are highly conserved in evolution across species (TRUE)

B. are present in vertebrate hosts (FALSE)

C. are specific to the individual organism (FALSE)

D. can recognise double stranded RNA (FALSE)

E. include lipopolysaccharide (TRUE)

Question 225

Factors that influence induction of tolerance include:-

A. the solubility of the antigen

B. the route of administration of the antigen

C. the dose of the antigen

D. the maturity of the immune system

E. chimaerism

Answer 225

Factors that influence induction of tolerance include:

A. the solubility of the antigen (TRUE)

B. the route of administration of the antigen (TRUE)

C. the dose of the antigen (TRUE)

D. the maturity of the immune system (TRUE)

E. chimaerism (TRUE)

Question 226

In the thymus

A. cortical epithelial cells mediate positive selection

B. T cells rearrange their alpha and beta TCR chains

C. T cells are trained to recognise specific pathogens

D. T cell clones with high affinity die by neglect

E. T cells are activated by follicular dendritic cell

Answer 226

In the thymus

A. cortical epithelial cells mediate positive selection (TRUE)

B. T cells rearrange their alpha and beta TCR chains (TRUE)

C. T cells are trained to recognise specific pathogens (FALSE)

D. T cell clones with high affinity die by neglect (FALSE)

E. T cells are activated by follicular dendritic cell (FALSE)

Question 227

Regarding tolerance

A. Immunologically privileged sites include the brain and the eye.

B. A graft from a non-identical individual of the same species is called an allograft

C. Most proteins are naturally highly immunogenic.

D. Cross–linking of surface Ig may result in apoptosis of B-lymphocytes in the bone marrow

E. Central tolerance occurs in the bone marrow and the thymus

Answer 227

Regarding tolerance

A. Immunologically privileged sites include the brain and the eye. (TRUE)

B. A graft from a non-identical individual of the same species is called an allograft (TRUE)

C. Most proteins are naturally highly immunogenic. (FALSE)

D. Cross–linking of surface Ig may result in apoptosis of B-lymphocytes in the bone marrow (TRUE)

E. Central tolerance occurs in the bone marrow and the thymus (TRUE)

Question 228

Haemolytic disease of the newborn due to RhD incompatibility depends upon the

A. baby possessing RhD antigens not present on the mother’s red cells

B. inability of the baby to react against the mother’s red cells

C. transplacental passage of IgM anti-RhD antibodies

D. transplacental passage of IgG anti-RhD antibodies

E. production of cytotoxic antibodies by the baby

Answer 228

Haemolytic disease of the newborn due to RhD incompatibility depends upon the

A. baby possessing RhD antigens not present on the mother’s red cells (TRUE)

B. inability of the baby to react against the mother’s red cells (FALSE)

C. transplacental passage of IgM anti-RhD antibodies (FALSE)

D. transplacental passage of IgG anti-RhD antibodies (TRUE)

E. production of cytotoxic antibodies by the baby (FALSE)

Question 229

Regarding blood group antigens

A. a universal donor has blood group AB

B. a person of blood group A has antibodies to the A antigen

C. haemolytic disease of the newborn involves complement mediated lysis of antibody coated foetal red blood cells

D. expression of the ABO blood group antigens is co-dominant

E. anti-rhesus antibodies (Rhogam) are used to prevent haemolytic disease of the newborn

Answer 229

Regarding blood group antigens

A. a universal donor has blood group AB (FALSE

B. a person of blood group A has antibodies to the A antigen (FALSE)

C. haemolytic disease of the newborn involves complement mediated lysis of antibody coated foetal red blood cells (FALSE)

D. expression of the ABO blood group antigens is co-dominant (TRUE)

E. anti-rhesus antibodies (Rhogam) are used to prevent haemolytic disease of the newborn (TRUE)

Question 230

Regarding hypersensitivity

A. Allergens do not stimulate strong IgE responses

B. People with blood group AB can receive blood of type O

C. The Arthus reaction is an example of type III hypersensitivity

D. Delayed type hypersensitivity is mediated by  B cells

E. Mast cells produce IgE which binds to allergens

Answer 230

Regarding hypersensitivity

A. Allergens do not stimulate strong IgE responses (FALSE)

B. People with blood group AB can receive blood of type O (TRUE)

C. The Arthus reaction is an example of type III hypersensitivity (TRUE)

D. Delayed type hypersensitivity is mediated by  B cells (FALSE)

E. Mast cells produce IgE which binds to allergens (FALSE)

Question 231

Type I hypersensitivity

A. involves IgE

B. involves mast cells

C. involves IgM

D. can be induced in some people by pollens

E. includes the Arthus reaction

Answer 231

Type I hypersensitivity

A. involves IgE (TRUE)

B. involves mast cells (TRUE)

C. involves IgM (TRUE)

D. can be induced in some people by pollens (TRUE)

E. includes the Arthus reaction (FALSE)

Question 232

Autoimmune disease

A. is always organ-specific

B. is rarely influenced by environmental factors

C. is always associated with specific HLA alleles

D. includes Type I insulin-dependent diabetes mellitus

E. may be T cell mediated

Answer 232

Autoimmune disease

A. is always organ-specific (FALSE)

B. is rarely influenced by environmental factors (FALSE)

C. is always associated with specific HLA alleles (FALSE

D. includes Type I insulin-dependent diabetes mellitus (TRUE)

E. may be T cell mediated (TRUE)

Question 233

In humans graft rejection

A. can be due to differences in β microglobulin subtype

B. can be due to minor histocompatibility differences

C. can be due to cytotoxic T lymphocytes

D. can be delayed by matching for MHC class I and class II

E. can occur even if the graft is from a sibling

Answer 233

In humans graft rejection

A. can be due to differences in β microglobulin subtype (FALSE)

B. can be due to minor histocompatibility differences (TRUE)

C. can be due to cytotoxic T lymphocytes (TRUE)

D. can be delayed by matching for MHC class I and class II (TRUE)

E. can occur even if the graft is from a sibling (TRUE)

Question 234

In transplantation

A. hyperacute rejection is often due to pre-existing antibody

B. an allograft can be a transplant between siblings

C. acute rejection may be T cell mediated

D. absence of lymphatic drainage is a common feature of immune privileged sites

E. HLA-matching is very important for liver transplant survival

Answer 234

In transplantation

A. hyperacute rejection is often due to pre-existing antibody (TRUE)

B. an allograft can be a transplant between siblings (TRUE)

C. acute rejection may be T cell mediated (TRUE)

D. absence of lymphatic drainage is a common feature of immune privileged sites (TRUE)

E. HLA-matching is very important for liver transplant survival (FALSE)

Question 235

The main cytokines responsible for immunosuppressing Th1 responses are

A. IFNγ

B. IL-8

C. IL-4

D. IL-10

E. TNFα

Answer 235

The main cytokines responsible for immunosuppressing Th1 responses are

A. IFNγ (FALSE)

B. IL-8 (FALSE)

C. IL-4 (TRUE)

D. IL-10 (TRUE)

E. TNFα (FALSE)

Question 236

In innate immune responses

A. Heat shock proteins are released by cells undergoing necrotic cell death

B. Lipopolysaccharide from gram negative bacteria is recognised by Toll-like receptor 4 (TLR4)

C. Membrane attack complex is only formed through activation of the classical complement pathway

D. The acute phase protein response can enhance complement activation

E. Neutrophils are most abundant during the early acute inflammatory response

Answer 236

In innate immune responses

A. Heat shock proteins are released by cells undergoing necrotic cell death (TRUE)

B. Lipopolysaccharide from gram negative bacteria is recognised by Toll-like receptor 4 (TLR4) (TRUE)

C. Membrane attack complex is only formed through activation of the classical complement pathway (FALSE)

D. The acute phase protein response can enhance complement activation (TRUE)

E. Neutrophils are most abundant during the early acute inflammatory response (TRUE)

Question 237

Phagocytic cells

A. Include neutrophils and eosinophils

B. Have receptors for complement components

C. Express pattern recognition receptors

D. Express receptors for chemokines

E. Are always very long lived.

Answer 237

Phagocytic cells

A. Include neutrophils and eosinophils (FALSE)

B. Have receptors for complement components (TRUE)

C. Express pattern recognition receptors (TRUE)

D. Express receptors for chemokines (TRUE)

E. Are always very long lived. (FALSE)

Question 238

The following are factors that promote or help sustain aspects of acute inflammation

A. cyclo-oxygenase 2

B. iNOS

C. Lipoxin

D. IL-10

E. Platelet activating factor

Answer 238

The following are factors that promote or help sustain aspects of acute inflammation

A. cyclo-oxygenase 2 (TRUE)

B. iNOS (TRUE)

C. Lipoxin (FALSE)

D. IL-10 (FALSE)

E. Platelet activating factor (TRUE)

Question 239

The following events help drive acute inflammation

A. Activation of tissue resident macrophages

B. Release of substance S by nerve cells

C. activation of tissue mast cells

D. Release of IL-6 by macrophages

E. cleavage of complement component C3.

Answer 239

The following events help drive acute inflammation

A. Activation of tissue resident macrophages (TRUE)

B. Release of substance S by nerve cells (TRUE)

C. activation of tissue mast cells (TRUE)

D. Release of IL-6 by macrophages (TRUE)

E. cleavage of complement component C3. (TRUE)

Question 240

Potent chemotactic factors (chemotaxins) for neutrophils include

A. C-reactive protein

B. TNFα

C. arachidonic acid

D. C3a

E. IL-8/CXCL8

Answer 240

Potent chemotactic factors (chemotaxins) for neutrophils include

A. C-reactive protein (FALSE)

B. TNFα (FALSE)

C. arachidonic acid (FALSE)

D. C3a (TRUE)

E. IL-8/CXCL8 (TRUE)

Question 241

NK cells

A. kill by MHC Class II restricted killing mechanisms

B. kill by antibody dependent cell cytotoxicity

C. contain perforin

D. secrete IFNγ

E. respond to IL-12

Answer 241

NK cells

A. kill by MHC Class II restricted killing mechanisms (FALSE)

B. kill by antibody dependent cell cytotoxicity (TRUE)

C. contain perforin (TRUE)

D. secrete IFNγ (TRUE)

E. respond to IL-12 (TRUE)

Question 242

In acute inflammation

A. TNF-a limits infection to the site of entry 

B. selectins control the early emigration of leukocytes into  sites of injury

C. A conformational change in LFA-1 helps neutrophils attach to the endothelial cell surfaces

D. IL-8/CXCL8 is an important chemokine regulating neutrophil chemotaxis

E. the life span of a neutrophil is relatively short (24-48 hrs)

Answer 242

In acute inflammation

A. TNF-a limits infection to the site of entry (TRUE)

B. selectins control the early emigration of leukocytes into  sites of injury (TRUE)

C. A conformational change in LFA-1 helps neutrophils attach to the endothelial cell surfaces (TRUE)

D. IL-8/CXCL8 is an important chemokine regulating neutrophil chemotaxis (TRUE)

E. the life span of a neutrophil is relatively short (24-48 hrs) (TRUE)

Question 243

In complement activation

A. C3b acts as an anaphylotoxin

B. C-reactive protein activates the lectin complement pathway

C. C5a has a chemotactic effect on neutrophil polymorphs

D. membrane-bound C3a facilitates phagocytosis

E. membrane attack is effected by the terminal C5-9 complex

Answer 243

In complement activation

A. C3b acts as an anaphylotoxin (FALSE)

B. C-reactive protein activates the lectin complement pathway (FALSE)

C. C5a has a chemotactic effect on neutrophil polymorphs (TRUE)

D. membrane-bound C3a facilitates phagocytosis (FALSE)

E. membrane attack is effected by the terminal C5-9 complex (TRUE)

Question 244

Complement

A. can be activated by antigen-antibody complexes

B. is inactivated by binding to acute phase proteins CRP and MBP

C. can induce degranulation of mast cells

D. can induce neutrophil chemotaxis

E. Is stable in solution

Answer 244

Complement

A. can be activated by antigen-antibody complexes (TRUE)

B. is inactivated by binding to acute phase proteins CRP and MBP (FALSE)

C. can induce degranulation of mast cells (TRUE)

D. can induce neutrophil chemotaxis (TRUE)

E. Is stable in solution (FALSE)

Question 245

The Fc portion of immunoglobulin

A. is required for mucosal transfer of IgA

B. is important for triggering IgE-mediated hypersensitivity

C. of IgG type can activate C1q

D. undergoes somatic hypermutation

E. contains both heavy and light chain domains

Answer 245

The Fc portion of immunoglobulin

A. is required for mucosal transfer of IgA (TRUE)

B. is important for triggering IgE-mediated hypersensitivity (TRUE)

C. of IgG type can activate C1q (TRUE)

D. undergoes somatic hypermutation (FALSE)

E. contains both heavy and light chain domains (FALSE)

Question 246

T cells possess an antigen receptor that

A. exists in both secreted and transmembrane forms

B. is monovalent

C. interacts with follicular dendritic cells

D. is generated by a process that involves allelic exclusion

E. is selected in the thymus by interaction with a combination of self MHC and foreign peptide.

Answer 246

T cells possess an antigen receptor that

A. exists in both secreted and transmembrane forms (FALSE)

B. is monovalent (TRUE)

C. interacts with follicular dendritic cells (FALSE)

D. is generated by a process that involves allelic exclusion (TRUE)

E. is selected in the thymus by interaction with a combination of self MHC and foreign peptide. (FALSE)

Question 247

Developing T cells

A. can express both CD4 and CD8

B. undergo positive selection to eliminate self-reactive cells

C. rearrange their T cell receptor genes before migration from bone marrow to thymus

D. are selected for high affinity for self MHC-peptide complexes

E. generate a repertoire that exhibits MHC restriction

Answer 247

Developing T cells

A. can express both CD4 and CD8 (TRUE)

B. undergo positive selection to eliminate self-reactive cells (FALSE)

C. rearrange their T cell receptor genes before migration from bone marrow to thymus (FALSE)

D. are selected for high affinity for self MHC-peptide complexes (FALSE)

E. generate a repertoire that exhibits MHC restriction (TRUE)

Question 248

T-cells in lymph nodes

A. may move into germinal centres

B. are mainly CD8 restricted

C. are phagocytic

D. arrive mainly via the lymphatic vessels

E. express surface immunoglobulin

Answer 248

T-cells in lymph nodes

A. may move into germinal centres (TRUE)

B. are mainly CD8 restricted (FALSE)

C. are phagocytic (FALSE)

D. arrive mainly via the lymphatic vessels (FALSE)

E. express surface immunoglobulin (FALSE)

Question 249

T cell receptor diversity is generated by

A. selection of different V, D and J region segments

B. junctional diversity

C. somatic hypermutation

D. isotype switching

E. pairing of different a and b chain segments

Answer 249

T cell receptor diversity is generated by

A. selection of different V, D and J region segments (TRUE)

B. junctional diversity (TRUE)

C. somatic hypermutation (FALSE)

D. isotype switching (FALSE)

E. pairing of different α and β chain segments (TRUE)

Question 250

Naïve peripheral T lymphocytes

A. are activated in primary lymphoid organs

B. have not yet rearranged their T-cell receptor genes

C. express either CD4 or CD8 co-receptor molecules

D. have been selected for high-affinity for self MHC/peptide

E. have undergone both positive and negative selection

Answer 250

Naïve peripheral T lymphocytes

A. are activated in primary lymphoid organs (FALSE)

B. have not yet rearranged their T-cell receptor genes (FALSE)

C. express either CD4 or CD8 co-receptor molecules (TRUE)

D. have been selected for high-affinity for self MHC/peptide (FALSE)

E. have undergone both positive and negative selection (TRUE)

Question 251

CD4

A. binds to an invariant portion of MHC Class I molecules

B. binds to an invariant portion of MHC Class II molecules

C. binds to peptide antigen

D. binds to the peptide binding site of MHC Class II

E. is expressed largely by B cells

Answer 251

CD4

A. binds to an invariant portion of MHC Class I molecules (FALSE)

B. binds to an invariant portion of MHC Class II molecules (TRUE)

C. binds to peptide antigen (FALSE)

D. binds to the peptide binding site of MHC Class II (FALSE)

E. is expressed largely by B cells (FALSE)

Question 252

T_H2 cells

A. mainly make IL-4

B. mainly make IFNγ

C. help activate CD8 expressing cytotoxic T cells

D. help eliminate intracellular bacteria

E. cause M1 macrophage activation

Answer 252

T_H2 cells

A. mainly make IL-4 (TRUE)

B. mainly make IFNγ (FALSE)

C. help activate CD8 expressing cytotoxic T cells (FALSE)

D. help eliminate intracellular bacteria (FALSE)

E. cause M1 macrophage activation (FALSE)

Question 253

Phagocytosis

A. is enhanced by opsonins

B. is used by B cells to internalise antigen

C. is often accompanied by increased production of reactive oxygen species

D. by natural killer cells helps clear viral infections

E. of bacteria can be inhibited by a capsule

Answer 253

Phagocytosis

A. is enhanced by opsonins (TRUE)

B. is used by B cells to internalise antigen (FALSE)

C. is often accompanied by increased production of reactive oxygen species (TRUE)

D. by natural killer cells helps clear viral infections (FALSE)

E. of bacteria can be inhibited by a capsule (TRUE)

Question 254

In an adaptive immune response

A. naïve T cells can meet self dendritic cells in parenchymal tissues and so become activated

B. production of IL4 by  promotes Th2 cellular responses

C. infection by helminths preferentially promotes a Th1 dominated response

D. macrophages are the most important cell type in activating naïve T cells

E. follicular dendritic cells present unprocessed antigen to developing B cells

Answer 254

In an adaptive immune response

A. naïve T cells can meet self dendritic cells in parenchymal tissues and so become activated (FALSE)

B. production of IL4 by  promotes Th2 cellular responses (TRUE)

C. infection by helminths preferentially promotes a Th1 dominated response (FALSE)

D. macrophages are the most important cell type in activating naïve T cells (FALSE)

E. follicular dendritic cells present unprocessed antigen to developing B cells (TRUE)

Question 255

Pattern Recognition Receptors include

A. Toll-like Receptors

B. MYD88

C. NOD-like Receptors

D. C-reactive protein

E. Membrane cofactor protein

Answer 255

Pattern Recognition Receptors include

A. Toll-like Receptors (TRUE)

B. MYD88 (FALSE)

C. NOD-like Receptors (TRUE) 

D. C-reactive protein (TRUE)

E. Membrane cofactor protein (FALSE)

Question 256

In complement activation

A. C3(H2O)Bb is an alternative pathway C3 convertase

B. Decay accelerating factor prevents the C3 convertase forming

C. Properdin stabilises the alternative pathway C3 convertase

D. C3b attaches non-covalently to microbial surfaces

E. MBL-associated proteases (MASPs) activate C4 and C2

Answer 256

In complement activation

A. C3(H2O)Bb is an alternative pathway C3 convertase (TRUE)

B. Decay accelerating factor prevents the C3 convertase forming (FALSE)

C. Properdin stabilises the alternative pathway C3 convertase (TRUE)

D. C3b attaches non-covalently to microbial surfaces (FALSE)

E. MBL-associated proteases (MASPs) activate C4 and C2 (TRUE)

Question 257

In the recruitment of leukocytes to inflammatory sites

A. Weak interactions between neutrophils and the endothelium are initially mediated by ICAMs, Ig superfamily molecules

B. CXCL8 is the principle chemokine involved in neutrophil recruitment

C. P-selectin bind to the carbohydrate component (Sialyl Lewisx) on neutrophils

D. Monocyte emigration into tissues involves the integrin VLA-4

E. Lymphocytes often emigrate into the acute inflammatory exudate

Answer 257

In the recruitment of leukocytes to inflammatory sites

A. Weak interactions between neutrophils and the endothelium are initially mediated by ICAMs, Ig superfamily molecules (FALSE)

B. CXCL8 is the principle chemokine involved in neutrophil recruitment (TRUE)

C. P-selectin bind to the carbohydrate component (Sialyl Lewisx) on neutrophils (TRUE)

D. Monocyte emigration into tissues involves the integrin VLA-4 (TRUE)

E. Lymphocytes often emigrate into the acute inflammatory exudate (TRUE)

Question 258

In the resolution of inflammation and repair

A. Neutrophils produce anti-inflammatory lipid-derived mediators.

B. Phagocytosis of apoptotic neutrophils by macrophages is anti-inflammatory

C. Endothelial cells are induced to increase collagen synthesis

D. Exudate is organised into a granuloma

E. Metalloproteinases are needed for tissue remodelling

Answer 258

In the resolution of inflammation and repair

A. Neutrophils produce anti-inflammatory lipid-derived mediators. (TRUE)

B. Phagocytosis of apoptotic neutrophils by macrophages is anti-inflammatory (TRUE)

C. Endothelial cells are induced to increase collagen synthesis (FALSE)

D. Exudate is organised into a granuloma (FALSE) 

E. Metalloproteinases are needed for tissue remodelling (TRUE)

Question 259

Major roles for the following factors are

A. IL-6 - activation of NK cells

B. IL-12 - induction of fever

C. TNFα - activation of vascular endothelium

D. VEGF - recruitment of fibroblasts to site of injury

E. IL-1 - direct induction of acute phase protein response 

Answer 259

Major roles for the following factors are

A. IL-6 - activation of NK cells (FALSE)

B. IL-12 - induction of fever (FALSE)

C. TNFα - activation of vascular endothelium (TRUE)

D. VEGF - recruitment of fibroblasts to site of injury (FALSE)

E. IL-1 - direct induction of acute phase protein response (FALSE)

Question 260

Regarding tolerance

A. Negative selection refers to the selection of T-cells that recognise foreign peptide bound to MHC molecules

B. Immunologically privileged sites include the eye

C. Anergised T cells die by apoptosis

D. The major role of the transcription factor AIRE is to ensure that more T-cells survive positive selection

E. Recognition of stromal cell antigen by developing B-cells results in apoptosis whilst recognition of soluble antigen results in anergy

Answer 260

Regarding tolerance

A. Negative selection refers to the selection of T-cells that recognise foreign peptide bound to MHC molecules (FALSE)

B. Immunologically privileged sites include the eye (TRUE)

C. Anergised T cells die by apoptosis (FALSE)

D. The major role of the transcription factor AIRE is to ensure that more T-cells survive positive selection (FALSE)

E. Recognition of stromal cell antigen by developing B-cells results in apoptosis whilst recognition of soluble antigen results in anergy (TRUE)

Question 261

Regarding autoimmunity

A. Complement component deficiency is a predisposing factor in systemic lupus erythematosus

B. Autoantibodies to acetylcholine lead to myasthenia gravis

C. In the EAE rat model of multiple sclerosis disease is due to CD8 T-cells

D. Most autoimmune diseases are equally prevalent in males and females

E. Most autoimmune diseases are associated with one or more mutant MHC molecules

Answer 261

Regarding autoimmunity

A. Complement component deficiency is a predisposing factor in systemic lupus erythematosus (TRUE)

B. Autoantibodies to acetylcholine lead to myasthenia gravis (FALSE)

C. In the EAE rat model of multiple sclerosis disease is due to CD8 T-cells (FALSE) 

D. Most autoimmune diseases are equally prevalent in males and females (FALSE)

E. Most autoimmune diseases are associated with one or more mutant MHC molecules (FALSE) 

Question 262

Among T cell subsets

A. CD4 Th2 cells secrete cytokines that cause mucus production in the gut.

B. Th17 cells protect against extracellular bacteria and fungi by stimulating the neutrophil response.

C. Inducible regulatory T cells (Tregs) develop in the thymus

D. Animals deficient in CD25 positive cells are susceptible to autoimmunity

E. Signature cytokines for TH1 and TH2 cells are IFNγ and IL-8 respectively

Answer 262

Among T cell subsets

A. CD4 Th2 cells secrete cytokines that cause mucus production in the gut. (TRUE)

B. Th17 cells protect against extracellular bacteria and fungi by stimulating the neutrophil response. (TRUE)

C. Inducible regulatory T cells (Tregs) develop in the thymus (FALSE)

D. Animals deficient in CD25 positive cells are susceptible to autoimmunity (TRUE)

E. Signature cytokines for TH1 and TH2 cells are IFNγ and IL-8 respectively (FALSE)

Question 263

In transplantation

A. Hyperacute rejection is generally T cell-mediated

B. Graft versus host rejection is beneficial for leukaemia patients

C. Direct recognition is due to the activation of donor-derived T cells by host antigen presenting cells

D. Lack of  lymphatic drainage is a common features of immunologically privileged sites

E. autologous transplant patients require long term immunosuppressive drug treatment

Answer 263

In transplantation

A. Hyperacute rejection is generally T cell-mediated (FALSE)

B. Graft versus host rejection is beneficial for leukaemia patients (TRUE)

C. Direct recognition is due to the activation of donor-derived T cells by host antigen presenting cells (FALSE)

D. Lack of  lymphatic drainage is a common features of immunologically privileged sites (TRUE)

E. autologous transplant patients require long term immunosuppressive drug treatment (FALSE)

Question 264

Immune complexes

A. Are usually cleared by circulating red blood cells

B. Are responsible for the Arthus reaction

C. Trigger mast cell activation via the low affinity FcγRIII receptor

D. Can result in false positive reactions in a complement fixation test

E. Formed in conditions of antigen excess are large and difficult to clear

Answer 264

Immune complexes

A. Are usually cleared by circulating red blood cells (TRUE)

B. Are responsible for the Arthus reaction (TRUE)

C. Trigger mast cell activation via the low affinity FcγRIII receptor (TRUE)

D. Can result in false positive reactions in a complement fixation test (TRUE)

E. Formed in conditions of antigen excess are large and difficult to clear (FALSE)

Question 265

Among cells of the immune system

A. T cells continually recirculate through lymph nodes, lymphatics and blood but B cells remain in lymphoid tissue

B. Lymphocytes enter lymph nodes from the blood via venous capillaries

C. Follicular Dendritic cells trap immune complexes and present intact antigen to B cells

D. NK cells, T cells and B cells all differentiate from the Common Lymphoid Progenitor

E. The spleen receives cells and molecules only from blood

Answer 265

Among cells of the immune system

A. T cells continually recirculate through lymph nodes, lymphatics and blood but B cells remain in lymphoid tissue (FALSE)

B. Lymphocytes enter lymph nodes from the blood via venous capillaries (TRUE)

C. Follicular Dendritic cells trap immune complexes and present intact antigen to B cells (TRUE)

D. NK cells, T cells and B cells all differentiate from the Common Lymphoid Progenitor (TRUE)

E. The spleen receives cells and molecules only from blood (TRUE)

Question 266

Regarding Antibodies

A. antibody light chains are produced by joining a variable, a diversity and a joining segment

B. May be bi-, tetra-  or deca-valent

C. Are found at low concentration in serum of newborn babies

D. Of both IgM and IgA classes are secreted in tears

E. secreted forms are produced as a result of ribosomal frame shifting

Answer 266

Regarding Antibodies

A. antibody light chains are produced by joining a variable, a diversity and a joining segment (FALSE)

B. May be bi-, tetra-  or deca-valent (TRUE)

C. Are found at low concentration in serum of newborn babies (FALSE)

D. Of both IgM and IgA classes are secreted in tears (TRUE)

E. secreted forms are produced as a result of ribosomal frame shifting (FALSE)

Question 267

With respect to the MHC

A. Class II molecules are expressed on most nucleated cells

B. Class II molecules associate with an endogenous peptide, CLIP

C. humans express 3 distinct isotypes of  both Class I and Class II molecules

D. MHC Class I molecules present peptides of 8-10 residues to T cells

E. MHC molecules are bound by T cell receptors and by co-receptors

Answer 267

With respect to the MHC

A. Class II molecules are expressed on most nucleated cells (FALSE)

B. Class II molecules associate with an endogenous peptide, CLIP (TRUE)

C. humans express 3 distinct isotypes of  both Class I and Class II molecules (TRUE)

D. MHC Class I molecules present peptides of 8-10 residues to T cells (TRUE)

E. MHC molecules are bound by T cell receptors and by co-receptors (TRUE)

Question 268

Regarding T cells

A. They are derived from bone marrow precursors which differentiate in the thymus

B. They undergo selection of their receptor repertoire during which the majority of T cells die due to negative selection

C. Co-stimulation required for activation of naïve T cells is provided by the CD4 or CD8 co-receptors

D. CD4 cells can differentiate into different types, each distinguished by distinct cytokine production

E. INF from NK cells and IL-4 from mast cells drive TH1 and TH2 cells respectively

Answer 268

Regarding T cells

A. They are derived from bone marrow precursors which differentiate in the thymus (TRUE)

B. They undergo selection of their receptor repertoire during which the majority of T cells die due to negative selection (FALSE)

C. Co-stimulation required for activation of naïve T cells is provided by the CD4 or CD8 co-receptors (FALSE)

D. CD4 cells can differentiate into different types, each distinguished by distinct cytokine production (TRUE)

E. INF from NK cells and IL-4 from mast cells drive TH1 and TH2 cells respectively (TRUE)

Question 269

In the generation of antibody responses

A. Thymus-independent responses are typically against microbial polysaccharides

B. B cells enter and leave lymph nodes via high endothelial venules

C. B cells present antigen that mainly enters the cell through interaction with the BCR

D. Cross-linking of CD40 promotes B cell proliferation

E. Follicular dendritic cells are activated in the periphery and travel to the lymph node to present antigen to T cells

Answer 269

In the generation of antibody responses

A. Thymus-independent responses are typically against microbial polysaccharides (TRUE)

B. B cells enter and leave lymph nodes via high endothelial venules (FALSE)

C. B cells present antigen that mainly enters the cell through interaction with the BCR (TRUE)

D. Cross-linking of CD40 promotes B cell proliferation (TRUE)

E. Follicular dendritic cells are activated in the periphery and travel to the lymph node to present antigen to T cells (FALSE)

Question 270

In lymphocyte receptor rearrangements

A. P-nucleotide addition is due to the activity of terminal deoxynucleotide transferase

B. Isotype switching allows B cells to use different kappa (κ) or lambda (λ) light chains

C. Immunoglobulin light chains and TCR β chains have no diversity segments

D. CDR1 is the most variable region of the receptor

E. T cells undergo somatic hypermutation

Answer 270

In lymphocyte receptor rearrangements

A. P-nucleotide addition is due to the activity of terminal deoxynucleotide transferase (FALSE)

B. Isotype switching allows B cells to use different kappa (κ) or lambda (λ) light chains (FALSE)

C. Immunoglobulin light chains and TCR β chains have no diversity segments (FALSE)

D. CDR1 is the most variable region of the receptor (FALSE)

E. T cells undergo somatic hypermutation (FALSE)

Question 271

In haematopoiesis

A. Neutrophils are a type of innate lymphoid cell

B. Platelets are derived from erythroblasts

C. Macrophages and dendritic cells can both be derived from monocytes

D. Plasma cells give rise to B cell memory responses

E. The common myeloid progenitor gives rise to both granulocytes and monocytes

Answer 271

In haematopoiesis

A. Neutrophils are a type of innate lymphoid cell (FALSE)

B. Platelets are derived from erythroblasts (FALSE) 

C. Macrophages and dendritic cells can both be derived from monocytes (TRUE)

D. Plasma cells give rise to B cell memory responses (FALSE)

E. The common myeloid progenitor gives rise to both granulocytes and monocytes (TRUE)

Question 272

The cell surface molecule

A. CD19 is a marker for T cells

B. CD8 binds to MHC class II molecules

C. CD45 is a low affinity receptor for IgG

D. CD4 is expressed on helper T cells

E. CD3 is involved in TCR signal transduction 

Answer 272

The cell surface molecule

A. CD19 is a marker for T cells (FALSE)

B. CD8 binds to MHC class II molecules (FALSE)

C. CD45 is a low affinity receptor for IgG (FALSE)

D. CD4 is expressed on helper T cells (TRUE)

E. CD3 is involved in TCR signal transduction (TRUE) 

Question 273

Pattern recognition receptors include:

A. TLR 5 which binds single stranded viral RNA

B. TLR 3 which in conjunction with CD14 recognises LPS

C. NOD1 which binds flagellin

D. TLR9 which binds lipoteichoic acid

E. NLRP3 (also known as NALP3) which recognises cholesterol crystals

Answer 273

Pattern recognition receptors include:

A. TLR 5 which binds single stranded viral RNA (FALSE)

B. TLR 3 which in conjunction with CD14 recognises LPS (FALSE)

C. NOD1 which binds flagellin (FALSE)

D. TLR9 which binds lipoteichoic acid (FALSE)

E. NLRP3 (also known as NALP3) which recognises cholesterol crystals (TRUE)

Question 274

In the acute inflammatory response,

A. Histamine comes from stored sources

B. Leukotrienes are actively synthesised

C. C3a, C3b and C5a are derived from precursors present in plasma

D. Bradykinin is plasma derived

E. Natural Killer Cells are rapidly recruited into the tissue spaces

Answer 274

In the acute inflammatory response,

A. Histamine comes from stored sources (TRUE)

B. Leukotrienes are actively synthesised (TRUE)

C. C3a, C3b and C5a are derived from precursors present in plasma (TRUE)

D. Bradykinin is plasma derived (TRUE)

E. Natural Killer Cells are rapidly recruited into the tissue spaces (FALSE)

Question 275

In the complement system:

A. The classical pathway is always first to act

B. The alternative pathway is the main pathway responsible for generating  C3b

C. Factor H speeds up activation of the alternative pathway

D. DAF disrupts the C3 convertase C3bBb

E. MCP makes C3b susceptible to cleavage by factor I.

Answer 275

In the complement system:

A. The classical pathway is always first to act (FALSE)

B. The alternative pathway is the main  pathway responsible for generating  C3b (TRUE)

C. Factor H speeds up activation of the alternative pathway (FALSE)

D. DAF disrupts the C3 convertase C3bBb (TRUE)

E. MCP makes C3b susceptible to cleavage by factor I. (TRUE)

Question 276

In the acute inflammatory response,

A. The kinin system makes thrombin

B. The fibrinolytic system makes bradykinin

C. Arachidonic acid metabolism leads to leukotrienes

D. Neutrophils follow a concentration gradient of CXCL8

E. IL-6 in the main cytokine that activates the acute phase response

Answer 276

In the acute inflammatory response,

A. The kinin system makes thrombin (FALSE)

B. The fibrinolytic system makes bradykinin (FALSE)

C. Arachidonic acid metabolism leads to leukotrienes (TRUE)

D. Neutrophils follow a concentration gradient of CXCL8 (TRUE)

E. IL-6 in the main cytokine that activates the acute phase response (TRUE)

Question 277

In the complement system:

A. The membrane attack complex is initiated by clevage of factor C5

B. C3b and C5b increase inflammation and enhance vascular permeability

C. Mannose-binding lectin interacts with MASP-1 and MASP-2

D. The classical C3 convertase is C4bC2a

E. C-reactive protein on bacterial surfaces recruits mannose binding protein.

Answer 277

In the complement system:

A. The membrane attack complex is initiated by clevage of factor C5 (TRUE)

B. C3b and C5b increase inflammation and enhance vascular permeability (FALSE)

C. Mannose-binding lectin interacts with MASP-1 and MASP-2 (TRUE)

D. The classical C3 convertase is C4bC2a (TRUE)

E. C-reactive protein on bacterial surfaces recruits mannose binding protein. (FALSE)

Question 278

Immunological tolerance:

A. Can involve regulatory T cells which are positive for FoxP3

B. Involves IDO which catabolises tryptophan

C. Depends on the transcription factor IPEX in the thymus

D. Requires that all B cells with receptors that recognise self undergo apoptosis or anergy

E. Is affected by B7 on the T cell interacting with CD28 on the APC

Answer 278

Immunological tolerance:

A. Can involve regulatory T cells which are positive for FoxP3 (TRUE)

B. Involves IDO which catabolises tryptophan (TRUE)

C. Depends on the transcription factor IPEX in the thymus (FALSE)

D. Requires that all B cells with receptors that recognise self undergo apoptosis or anergy (FALSE)

E. Is affected by B7 on the T cell interacting with CD28 on the APC (FALSE)

Question 279

Immune hypersensitivity

A. of type I involves mast cells

B. of type III involves mast cells

C. of type II may be tested by the Arthus reaction

D. of type IV involves recruitment of macrophages

E. to the drug abacavir occurs in individuals who express HLA-B*57

Answer 279

Immune hypersensitivity

A. of type I involves mast cells (TRUE)

B. of type III involves mast cells (TRUE)

C. of type II may be tested by the Arthus reaction (FALSE) CHECK

D. of type IV involves recruitment of macrophages (TRUE)

E. to the drug abacavir occurs in individuals who express HLA-B*57 (TRUE)

Question 280

In transplantation,

A. Direct recognition involves donor derived dendritic cells

B. Indirect recognition occurs only when MHC molecules are mismatched

C. HLA matching is more important for haemopoietic stem cell transplants than for liver transplants

D. HLA typing is not necessary in the autologous situation

E. A GvH response is never advantageous

Answer 280

In transplantation,

A. Direct recognition involves donor derived dendritic cells (TRUE)

B. Indirect recognition occurs only when MHC molecules are mismatched (FALSE)

C. HLA matching is more important for haemopoietic stem cell transplants than for liver transplants (TRUE)

D. HLA typing is not necessary in the autologous situation (TRUE)

E. A GvH response is never advantageous (FALSE) 

Question 281

T helper cells

A. are activated in the thymus

B. can present antigen on MHC class I to cytotoxic T cells

C. are required for the initiation of all IgM antibody production

D. enter lymph nodes through high endothelial venules

E. can activate macrophages

Answer 281

T helper cells

A. are activated in the thymus (FALSE)

B. can present antigen on MHC class I to cytotoxic T cells (TRUE)

C. are required for the initiation of all IgM antibody production (FALSE)

D. enter lymph nodes through high endothelial venules (TRUE) 

E. can activate macrophages (TRUE)

Question 282

Influenza virus

A. Is a negative sense RNA virus 

B. Contains a virion associated RNA polymerase

C. Replicates in the nucleus

D. Most likely uses the pig as the natural reservoir

E. Binds to cells using HA which recognizes host heparin sulphate

Answer 282

Influenza virus

A. Is a negative sense RNA virus (ΤRUE)

B. Contains a virion associated RNA polymerase (ΤRUE)

C. Replicates in the nucleus (ΤRUE)

D. Most likely uses the pig as the natural reservoir (FALSE)

E. Binds to cells using HA which recognizes host heparin sulphate (FALSE)

Question 283

Superficial viral infections

A. Often use different portals of entry and exit

B. Usually have long incubation periods

C. Are usually of short duration

D. Include smallpox

E. Varicella-zoster virus

Answer 283

Superficial viral infections

A. Often use different portals of entry and exit (FALSE)

B. Usually have long incubation periods (FALSE)

C. Are usually of short duration (ΤRUE)

D. Include smallpox (FALSE)

E. Varicella-zoster virus (FALSE)

Question 284

Epstein Bar Virus

A. Is a herpes virus

B. Is associated with neoplasia

C. Can establish latency

D. Infects sensory neurons

E. Enters through the oral epithelium

Answer 284

Epstein Bar Virus

A. Is a herpes virus (ΤRUE)

B. Is associated with neoplasia (ΤRUE)

C. Can establish latency (ΤRUE)

D. Infects sensory neurons (FALSE)

E. Enters through the oral epithelium (ΤRUE)

Question 285

The human immunodeficiency virus

A. Is a lentivirus

B. Transmits between hosts mainly using CD4 and CXCR4 receptors

C. Generates a provirus using a RNA-dependent RNA polymerase

D. Has a haploid genome

E. Generates gp120 and gp41 using an IRES mechanism

Answer 285

The human immunodeficiency virus

A. Is a lentivirus (ΤRUE)

B. Transmits between hosts mainly using CD4 and CXCR4 receptors (FALSE)

C. Generates a provirus using a RNA-dependent RNA polymerase (FALSE)

D. Has a haploid genome (FALSE)

E. Generates gp120 and gp41 using an IRES mechanism (FALSE)

Question 286

The antiviral agent

A. Acyclovir causes DNA chain termination

B. AZT  incorporates into reverse transcriptase

C. AZT is phosphorylated by host kinases

D. Tamiflu is a haemagglutinin homologue

E. Acyclovir is effective against herpesviruses

Answer 286

The antiviral agent

A. Acyclovir causes DNA chain termination (ΤRUE)

B. AZT  incorporates into reverse transcriptase (FALSE)

C. AZT is phosphorylated by host kinases (ΤRUE)

D. Tamiflu is a haemagglutinin homologue (FALSE)

E. Acyclovir is effective against herpesviruses (ΤRUE)

Question 287

Viral

A. Cytokine, vIL-10 induces TH1 responses

B. Inhibitors of the jack stat pathway block PKR and OAS synthesis

C. Env proteins are part of the capsid coat

D. Reactivation is a concern in xenotransplantation

E. Influenza epidemics are caused by antigenic drift

Answer 287

Viral

A. Cytokine, vIL-10 induces TH1 responses (FALSE)

B. Inhibitors of the jack stat pathway block PKR and OAS synthesis (ΤRUE)

C. Env proteins are part of the capsid coat (FALSE)

D. Reactivation is a concern in xenotransplantation (ΤRUE)

E. Influenza epidemics are caused by antigenic drift (ΤRUE)

Question 288

In viral infections

A. Yellow fever and rabies infect multiple host species

B. Rubella can cross the placenta

C. AIDS is a zoonoses

D. Herpes simplex can be transferred in breast milk

E. Measles is antigenically stable

Answer 288

In viral infections

A. Yellow fever and rabies infect multiple host species (ΤRUE)

B. Rubella can cross the placenta (ΤRUE)

C. AIDS is a zoonoses (ΤRUE)

D. Herpes simplex can be transferred in breast milk (ΤRUE)

E. Measles is antigenically stable (ΤRUE)

Question 289

In viral infections

A. Hepatitis C is usually persistent

B. 90% of female neonates fail to clear the Hepatitis B

C.  Shingles is due to reinfection by varicella-zoster virus

D. Rabies virus spreads through macrophage migration

E. Rabies can be controlled by vaccination post infection

Answer 289

In viral infections

A. Hepatitis C is usually persistent (ΤRUE)

B. 90% of female neonates fail to clear the Hepatitis B (FALSE)

C.  Shingles is due to reinfection by varicella-zoster virus (FALSE)

D. Rabies virus spreads through macrophage migration (FALSE)

E. Rabies can be controlled by vaccination post infection (ΤRUE)

Question 290

Reactivation of latent infection may be caused by

A. Stimulation of sensory neurons (Herpes simplex)

B. Macrophage differentiation

C. Stimulation of motor neurons (Polio virus)

D. B-cell differentiation

E. Activation of endogenous retroviruses in xenotransplantation

Answer 290

Reactivation of latent infection may be caused by

A. Stimulation of sensory neurons (Herpes simplex) (ΤRUE)

B. Macrophage differentiation (ΤRUE)

C. Stimulation of motor neurons (Polio virus) (FALSE)

D. B-cell differentiation (ΤRUE)

E. Activation of endogenous retroviruses in xenotransplantation (ΤRUE)

Question 291

HIV

A. Transmission is reduced in individuals lacking CCR5

B.  Uses ribosomal frameshifting to control protein expression

C. infected individuals may be asymptomatic

D. is controlled by vaccination

E. contains a tRNA in the virion particle

Answer 291

HIV

A. Transmission is reduced in individuals lacking CCR5 (ΤRUE)

B.  Uses ribosomal frameshifting to control protein expression (ΤRUE)

C. infected individuals may be asymptomatic (ΤRUE)

D. is controlled by vaccination (FALSE)

E. contains a tRNA in the virion particle (ΤRUE)

Question 292

Viruses

A. That are transmitted via water include Hepatitis A

B. That are transmitted by respiratory aerosol are often not very contagious

C. that cross the placenta include CMV

D. that exhibit horizontal transmission include measles

E. generally cause cell lysis

Answer 292

Viruses

A. That are transmitted via water include Hepatitis A (ΤRUE)

B. That are transmitted by respiratory aerosol are often not very contagious (FALSE)

C. that cross the placenta include CMV (ΤRUE)

D. that exhibit horizontal transmission include measles (ΤRUE)

E. generally cause cell lysis (ΤRUE)

Question 293

Live attenuated vaccines

A. are used against measles

B. may revert to virulence

C. include the vaccinia virus

D. may be genetically engineered

E. are used to control rabies

Answer 293

Live attenuated vaccines (ΤRUE)

A. are used against measles (ΤRUE)

B. may revert to virulence (ΤRUE)

C. include the vaccinia virus (FALSE)

D. may be genetically engineered (ΤRUE)

E. are used to control rabies (FALSE)

Question 294

Influenza

A. pandemics are associated with viral latency

B. H5N1 is associated with high human fatality in infected individuals

C. Virus that infects humans prefer sialic acid with an a 2’-6’ link

D. DNA polymerase mutates to suit its host

E. Virus protein NS1 can modulate interferon resistance

Answer 294

Influenza

A. pandemics are associated with viral latency (FALSE)

B. H5N1 is associated with high human fatality in infected individuals (ΤRUE)

C. Virus that infects humans prefer sialic acid with an a 2’-6’ link (ΤRUE)

D. DNA polymerase mutates to suit its host (FALSE) 

E. Virus protein NS1 can modulate interferon resistance (ΤRUE)

Question 295

Regarding the outcome of infection

A. Retroviruses can replicate in cells without killing them

B. Papilloma virus sometimes fails to produce capsid protein

C. Non-enveloped DNA viruses are lytic

D. Non-productive replication can result in cell transformation

E. Helper virus is required by rouse sarcoma virus

Answer 295

Regarding the outcome of infection

A. Retroviruses can replicate in cells without killing them (ΤRUE)

B. Papilloma virus sometimes fails to produce capsid protein (ΤRUE)

C. Non-enveloped DNA viruses are lytic (ΤRUE)

D. Non-productive replication can result in cell transformation (ΤRUE)

E. Helper virus is required by rouse sarcoma virus (ΤRUE)

Question 296

For herpesviruses

A. Transcription occurs in the nucleus

B. Assembly occurs in the nucleus

C. The viral DNA alone is potentially infectious

D. Transcription uses a virus encoded DNA dependent RNA polymerase

E. Capsid proteins are made in the nucleus

Answer 296

For herpesviruses

A. Transcription occurs in the nucleus (ΤRUE)

B. Assembly occurs in the nucleus (ΤRUE)

C. The viral DNA alone is potentially infectious (ΤRUE)

D. Transcription uses a virus encoded DNA dependent RNA polymerase (FALSE)

E. Capsid proteins are made in the nucleus (FALSE)

Question 297

Measles virus

A. Requires the nucleus for replication

B. Requires a virion associated polymerase to initiate replication

C. Assembles in the cytoplasm

D. Is a negative strand RNA virus

E. Nucleic acid is infectious

Answer 297

Measles virus

A. Requires the nucleus for replication (FALSE)

B. Requires a virion associated polymerase to initiate replication (ΤRUE)

C. Assembles in the cytoplasm (ΤRUE)

D. Is a negative strand RNA virus (ΤRUE)

E. Nucleic acid is infectious (FALSE) 

Question 298

The following statements are correct

A. The term virion could include the virus envelope

B. The capsid is the virus protein coat that surrounds nucleic acid

C. Viral nucleic acid is either DNA or RNA

D. All bacteria and viruses have haploid genomes

E. RNA viruses generally have smaller genomes than DNA viruses

Answer 298

The following statements are correct

A. The term virion could include the virus envelope (ΤRUE)

B. The capsid is the virus protein coat that surrounds nucleic acid (ΤRUE)

C. Viral nucleic acid is either DNA or RNA (ΤRUE)

D. All bacteria and viruses have haploid genomes (FALSE) 

E. RNA viruses generally have smaller genomes than DNA viruses (ΤRUE)

Question 299

The following statements are correct

A. All enveloped viruses are physically unstable

B. Most systemic viruses spread via blood and or lymph

C. Smallpox virus has an animal reservoir

D. A bacteriophage is a bacterial virus

E. Viruses can be larger than bacteria

Answer 299

The following statements are correct

A. All enveloped viruses are physically unstable (ΤRUE)

B. Most systemic viruses spread via blood and or lymph (ΤRUE)

C. Smallpox virus has an animal reservoir (FALSE)

D. A bacteriophage is a bacterial virus (ΤRUE)

E. Viruses can be larger than bacteria (ΤRUE)

Question 300

The RNA virus

A. genome may code for more than a thousand polypeptides

B. genome may be circular

C. measles may be cell-associated

D. poliovirus can be transmitted over large distances

E. vaccinia expresses its own epidermal growth factor

Answer 300

The RNA virus

A. genome may code for more than a thousand polypeptides (FALSE)

B. genome may be circular (FALSE)

C. measles may be cell-associated (ΤRUE)

D. poliovirus can be transmitted over large distances (ΤRUE)

E. vaccinia expresses its own epidermal growth factor (ΤRUE)

Question 301

In viral detection and control

A. recognition by  PRRs often culminates in activation of NFκB or interferon response factors

B. production of  interferon alpha/beta induces an antiviral state

C. PRRs may be intracellular

D. Most mammalian viruses attempt to block/avoid IFNs

E. Cytokines that drive cell mediated immunity include IL-4

Answer 301

In viral detection and control

A. recognition by  PRRs often culminates in activation of NFκB or interferon response factors (ΤRUE)

B. production of  interferon alpha/beta induces an antiviral state (ΤRUE)

C. PRRs may be intracellular (ΤRUE)

D. Most mammalian viruses attempt to block/avoid IFNs (ΤRUE)

E. Cytokines that drive cell mediated immunity include IL-4 (FALSE)

Question 302

Viruses exhibiting vertical transmission include

A. HIV 

B. CMV 

C. Parvovirus

D. Rhinovirus

E. Adenovirus

Answer 302

Viruses exhibiting vertical transmission include

A. HIV (ΤRUE)

B. CMV (ΤRUE)

C. Parvovirus (ΤRUE)

D. Rhinovirus (FALSE) 

E. Adenovirus (FALSE)

Question 303

Members of the herpes virus family

A. will replicate normally in enucleated cells

B. have a single stranded DNA genome

C. all establish latency in neuronal cells

D. are non-enveloped

E. are not associated with malignant transformation of host cells

Answer 303

Members of the herpes virus family

A. will replicate normally in enucleated cells (FALSE)

B. have a single stranded DNA genome (FALSE)

C. all establish latency in neuronal cells (FALSE)

D. are non-enveloped (FALSE)

E. are not associated with malignant transformation of host cells (FALSE)

Question 304

Poliovirus

A. is a small single stranded DNA virus

B. is normally transmitted by the respiratory route

C. rapidly induces host cell shut-off

D. is antigenically stable

E. is translated by a cap-independent mechanism

Answer 304

Poliovirus

A. is a small single stranded DNA virus (FALSE)

B. is normally transmitted by the respiratory route (FALSE)

C. rapidly induces host cell shut-off (ΤRUE)

D. is antigenically stable (ΤRUE)

E. is translated by a cap-independent mechanism (ΤRUE)

Question 305

Each of the following viruses is commonly transmitted by the following route

A. Hepatitis A virus : faeco-oral

B. Yellow Fever Virus : respiratory aerosol

C. Hepatitis B : blood contact

D. Rotavirus : insect vectors

E. Cytomeglovirus : oral/sexual contact

Answer 305

Each of the following viruses is commonly transmitted by the following route

A. Hepatitis A virus : faeco-oral (ΤRUE)

B. Yellow Fever Virus : respiratory aerosol (FALSE)

C. Hepatitis B : blood contact (ΤRUE)

D. Rotavirus : insect vectors (FALSE)

E. Cytomeglovirus : oral/sexual contact (ΤRUE)

Question 306

Vaccination against measles virus

A. uses a live attenuated virus vaccine

B. uses a genetically engineered subunit vaccine

C. aims to achieve a level of herd immunity sufficient to prevent epidemics

D. requires regular modification of the vaccine to cope with antigenic variation by circulation measles virus

E. will never eliminate the infection because of the reservoir of virus in animal populations

Answer 306

Vaccination against measles virus

A. uses a live attenuated virus vaccine (ΤRUE)

B. uses a genetically engineered subunit vaccine (FALSE)

C. aims to achieve a level of herd immunity sufficient to prevent epidemics (ΤRUE)

D. requires regular modification of the vaccine to cope with antigenic variation by circulation measles virus (FALSE)

E. will never eliminate the infection because of the reservoir of virus in animal populations (FALSE)

Question 307

Influenza virus

A. Has a nucleocapsid with helical symmetry

B. Has a negative sense RNA genome

C. Genome replicates in the host cell nucleus

D. Enters cells by endocytosis

E. Is dependent on sialic acid for cell entry

Answer 307

Influenza virus

A. Has a nucleocapsid with helical symmetry (ΤRUE)

B. Has a negative sense RNA genome (ΤRUE)

C. Genome replicates in the host cell nucleus (ΤRUE)

D. Enters cells by endocytosis (ΤRUE)

E. Is dependent on sialic acid for cell entry (ΤRUE)

Question 308

The respiratory tract is the most common entry route for

A. Influenza virus

B. Polio virus

C. Varicella zoster virus

D. Measles virus

E. Hepatitis B virus

Answer 308

The respiratory tract is the most common entry route for

A. Influenza virus (ΤRUE)

B. Polio virus (FALSE)

C. Varicella zoster virus (ΤRUE)

D. Measles virus (ΤRUE)

E. Hepatitis B virus (FALSE)

Question 309

Human immunodeficiency virus

A. is an acutely transforming retrovirus

B. gene expression is dependent on host DNA-dependent RNA polymerase II

C. replication is inhibited by acyclovir

D. can latently infect CD4 positive helper T cells

E. can be eliminated from the host by highly active anti-retroviral therapy

Answer 309

Human immunodeficiency virus

A. is an acutely transforming retrovirus (FALSE)

B. gene expression is dependent on host DNA-dependent RNA polymerase II (ΤRUE)

C. replication is inhibited by acyclovir (FALSE)

D. can latently infect CD4 positive helper T cells (ΤRUE)

E. can be eliminated from the host by highly active anti-retroviral therapy (FALSE)

Question 310

Live attenuated vaccines are used to control

A. Hepatitis B

B. Rabies 

C. Varicella zoster virus.

D. Foot and mouth disease virus

E. Human papillomavirus.

Answer 310

Live attenuated vaccines are used to control

A. Hepatitis B (FALSE)

B. Rabies (ΤRUE)

C. Varicella zoster virus. (ΤRUE)

D. Foot and mouth disease virus (FALSE)

E. Human papillomavirus. (FALSE)

Question 311

The following viruses normally establish chronic infections

A. Measles virus.

B. Hepatitis A.

C. Hepatitis C

D. Hepatitis B

E. Herpes simplex virus

Answer 311

The following viruses normally establish chronic infections

A. Measles virus. (FALSE)

B. Hepatitis A. (FALSE)

C. Hepatitis C (ΤRUE)

D. Hepatitis B (ΤRUE)

E. Herpes simplex virus (FALSE)

Question 312

Poliovirus

A. Induces host cell shut-off by cleaving 5’-caps from host mRNA

B. Encodes a single polyprotein that is cleaved by protease activity

C. Increases cellular pools of dNTPs through thymidine kinase activity

D. Contains an internal ribosome entry site at the 5’ end of the genome

E. Has a poly-(A) tail at the 3’ end of the viral genome 

Answer 312

Poliovirus

A. Induces host cell shut-off by cleaving 5’-caps from host mRNA (FALSE)

B. Encodes a single polyprotein that is cleaved by protease activity (ΤRUE)

C. Increases cellular pools of dNTPs through thymidine kinase activity (FALSE)

D. Contains an internal ribosome entry site at the 5’ end of the genome (ΤRUE)

E. Has a poly-(A) tail at the 3’ end of the viral genome (ΤRUE)

Question 313

Viruses directly interfere with interferon by

A. Inhibiting the JAK-STAT signalling pathway

B. Expressing an activated form of src tyrosine kinase

C. Activating pathogen recognition receptors

D. Releasing proteins that bind to interferon in solution

E. Down regulating MHC class I expression

Answer 313

Viruses directly interfere with interferon by

A. Inhibiting the JAK-STAT signalling pathway (ΤRUE)

B. Expressing an activated form of src tyrosine kinase (FALSE)

C. Activating pathogen recognition receptors (FALSE)

D. Releasing proteins that bind to interferon in solution (ΤRUE)

E. Down regulating MHC class I expression (FALSE)

Question 314

Epstein Barr Virus

A. Is a transforming retrovirus

B. Can cause B cell lymphomas

C. Establishes latency in pre-monocytes

D. Gains entry to the host primarily via the oropharynx

E. Has a single-stranded DNA genome 

Answer 314

Epstein Barr Virus

A. Is a transforming retrovirus (FALSE)

B. Can cause B cell lymphomas (ΤRUE)

C. Establishes latency in pre-monocytes (FALSE)

D. Gains entry to the host primarily via the oropharynx (ΤRUE)

E. Has a single-stranded DNA genome (FALSE)

Question 315

Infection of neuronal tissue is central to the life cycle of

A. Herpes simplex virus type-2

B. Measles virus

C. Rabies virus

D. Varicella-zoster virus

E. Poliovirus

Answer 315

Infection of neuronal tissue is central to the life cycle of

A. Herpes simplex virus type-2 (ΤRUE)

B. Measles virus (FALSE)

C. Rabies virus (ΤRUE)

D. Varicella-zoster virus (ΤRUE)

E. Poliovirus (FALSE)

Question 316

Regarding virus genome replication,

A. Positive strand RNA viruses require RNA-dependent RNA polymerase to be packaged in the virion

B. Some negative strand RNA viruses replicate in the nucleus

C. All DNA viruses replicate in the nucleus

D. Purified poxvirus DNA is infectious

E. Retroviruses replicate via a negative strand RNA intermediate

Answer 316

Regarding virus genome replication,

A. Positive strand RNA viruses require RNA-dependent RNA polymerase to be packaged in the virion (FALSE)

B. Some negative strand RNA viruses replicate in the nucleus (ΤRUE)

C. All DNA viruses replicate in the nucleus (FALSE)

D. Purified poxvirus DNA is infectious (FALSE)

E. Retroviruses replicate via a negative strand RNA intermediate (FALSE)

Question 317

Measles virus

A. Is controlled by a subunit vaccine

B. Has a non-segmented negative-strand RNA genome

C. Is highly infectious

D.Is enveloped

E. Can infect neurons

Answer 317

Measles virus

A. Is controlled by a subunit vaccine (FALSE)

B. Has a non-segmented negative-strand RNA genome (ΤRUE)

C. Is highly infectious (ΤRUE)

D. Is enveloped (ΤRUE)

E. Can infect neurons (ΤRUE)

Question 318

Viruses that use the respiratory tract to enter their hosts include:

A.  Adenovirus

B.  Hepatitis A virus

C. Rhinovirus

D. Bluetongue virus

E. Varicella-zoster virus

Answer 318

Viruses that use the respiratory tract to enter their hosts include:

A.  Adenovirus (ΤRUE)

B.  Hepatitis A virus (FALSE)

C. Rhinovirus (ΤRUE)

D. Bluetongue virus (FALSE)

E. Varicella-zoster virus (ΤRUE)

Question 319

The following are important for host innate immune responses to viruses:

A.  Sensing virus infection through pattern recognition receptors

B. Apoptosis

C. Inhibiting JAK-STAT signalling

D. Generating virus-specific neutralising antibodies

E. Natural killer cells

Answer 319

The following are important for host innate immune responses to viruses:

A.  Sensing virus infection through pattern recognition receptors (ΤRUE)

B. Apoptosis (ΤRUE)

C. Inhibiting JAK-STAT signalling (FALSE)

D. Generating virus-specific neutralising antibodies (FALSE)

E. Natural killer cells (ΤRUE)

Question 320

To enhance virus replication,

A. Polioviruses express a protease that inhibits cellular mRNA translation

B.  Vaccinia virus stimulates neighbouring cells to divide in order to facilitate virus transmission

C. Papillomaviruses drive the development of cancers specifically to enhance virus production

D. Herpesviruses express enzymes which increase the dNTP pool in the cell

E. Poxviruses stimulate an Interferon response through the production of Interferon-binding proteins 

Answer 320

To enhance virus replication,

A. Polioviruses express a protease that inhibits cellular mRNA translation (ΤRUE)

B.  Vaccinia virus stimulates neighbouring cells to divide in order to facilitate virus transmission (ΤRUE)

C. Papillomaviruses drive the development of cancers specifically to enhance virus production (FALSE)

D. Herpesviruses express enzymes which increase the dNTP pool in the cell (ΤRUE)

E. Poxviruses stimulate an Interferon response through the production of Interferon-binding proteins (FALSE)

Question 321

Viruses that commonly establish persistent (chronic or latent) infections include:

A. Foot and mouth disease virus

B.  Rotavirus

C. Herpes simplex virus

D. Human cytomegalovirus

E. Hepatitis C virus

Answer 321

Viruses that commonly establish persistent (chronic or latent) infections include:

A. Foot and mouth disease virus (FALSE)

B. Rotavirus (FALSE)

C. Herpes simplex virus (ΤRUE)

D. Human cytomegalovirus (ΤRUE)

E. Hepatitis C virus (ΤRUE)

Question 322

Influenza viruses:

A. Can have filamentous or spherical morphology

B. Encode an RNA-dependent DNA-polymerase

C. Require a high pH environment to fuse with cellular membranes

D. Encode 3 viral envelope proteins

E. Cause seasonal epidemics due to the process of antigenic drift

Answer 322

Influenza viruses:

A. Can have filamentous or spherical morphology (ΤRUE)

B. Encode an RNA-dependent DNA-polymerase (FALSE)

C. Require a high pH environment to fuse with cellular membranes (FALSE)

D. Encode 3 viral envelope proteins (ΤRUE)

E. Cause seasonal epidemics due to the process of antigenic drift (ΤRUE)

Question 323

Smallpox eradication was facilitated by the following:

A.  Smallpox is an easily recognised disease

B.  The virus has little antigenic diversity because its RNA genome replicates with high fidelity

C. The virus establishes a persistent infection in humans

D. The vaccine is low-cost and easy to administer

E. The animal reservoir for smallpox was also eliminated through vaccination

Answer 323

Smallpox eradication was facilitated by the following:

A.  Smallpox is an easily recognised disease (ΤRUE)

B.  The virus has little antigenic diversity because its RNA genome replicates with high fidelity (FALSE)

C. The virus establishes a persistent infection in humans (FALSE)

D. The vaccine is low-cost and easy to administer (ΤRUE)

E. The animal reservoir for smallpox was also eliminated through vaccination (FALSE)

Question 324

During HIV infection,

A.  Expression of the viral envelope protein is controlled by splicing

B.  The co-receptor CCR5 is mainly important during late stages of infection

C. Reverse transcription is primed by an mRNA that is packaged in the virion

D. Infectious virus formation requires post-translational cleavage of gag and pol

E. The virus is protected from neutralising antibodies by a glycan shield

Answer 324

During HIV infection,

A.  Expression of the viral envelope protein is controlled by splicing (ΤRUE)

B.  The co-receptor CCR5 is mainly important during late stages of infection (FALSE)

C. Reverse transcription is primed by an mRNA that is packaged in the virion (FALSE)

D. Infectious virus formation requires post-translational cleavage of gag and pol (ΤRUE)

E. The virus is protected from neutralising antibodies by a glycan shield (ΤRUE)

Question 325

The following statements are TRUE

A. Cryptococcus neoformans causes a slowly progressive disease   

B. Invasive infections with Aspergillis fumigates has high fatality   

C. Candida albicans is a common commensal organism of human mucous membranes   

D. Structural barriers play a minor role in innate protection from fungal infection

E. Protein synthesis in fungi can be blocked by griseofulvin

Answer 325

The following statements are TRUE

A. Cryptococcus neoformans causes a slowly progressive disease (TRUE)

B. Invasive infections with Aspergillis fumigates has high fatality (TRUE)

C. Candida albicans is a common commensal organism of human mucous membranes (TRUE)

D. Structural barriers play a minor role in innate protection from fungal infection (FALSE)

E. Protein synthesis in fungi can be blocked by griseofulvin (FALSE)

Question 326

Regarding fungi

A. most are saprophytes       

B. many are parasites of humans and animals         

C. they can be eukaryotes or prokaryotes    

D. they have a cell wall containing both chitin and glucans 

E. many, but not all, are dimorphic    

Answer 326

Regarding fungi

A. most are saprophytes (TRUE)

B. many are parasites of humans and animals (FALSE)

C. they can be eukaryotes or prokaryotes (FALSE)    

D. they have a cell wall containing both chitin and glucans (TRUE)

E. many, but not all, are dimorphic (TRUE)

Question 327

In fungi

A. DNA is organised in chromosomes within a membrane-bound nucleus 

B. hyphae are branching cylinders that grow by cell division           

C. at 37°C, the spores of dimorphic fungi germinate into yeasts     

D.  the azole toxin drug Fluconazole inhibits the synthesis of ergotamine  

E. the echinocandin anti-fungal drug Caspofungin inhibits the synthesis of glucan, a component of the cell wall

Answer 327

In fungi

A. DNA is organised in chromosomes within a membrane-bound nucleus (TRUE)

B. hyphae are branching cylinders that grow by cell division (TRUE)

C. at 37°C, the spores of dimorphic fungi germinate into yeasts (TRUE)

D.  the azole toxin drug Fluconazole inhibits the synthesis of ergotamine (FALSE)

E. the echinocandin anti-fungal drug Caspofungin inhibits the synthesis of glucan, a component of the cell wall (TRUE)

Question 328

In host defence against fungal infections      

A. the pattern recognition receptor Dectin-1 recognises fungal glucan       

B. deficiency of interleukin IL-17 predisposes to superficial fungal infections         

C. antibody deficiency predisposes to filamentous mould infections          

D. impaired function of macrophages and T cells predisposes to yeast       

E. a pre-existing lung cavity predisposes to an aspergilloma 

Answer 328

In host defence against fungal infections      

A. the pattern recognition receptor Dectin-1 recognises fungal glucan (TRUE)     

B. deficiency of interleukin IL-17 predisposes to superficial fungal infections (TRUE)        

C. antibody deficiency predisposes to filamentous mould infections (FALSE)        

D. impaired function of macrophages and T cells predisposes to yeast (TRUE)

E. a pre-existing lung cavity predisposes to an aspergilloma (TRUE)

Question 329

In humans      

A.  superficial fungal infections of hair or nails rarely cause disseminated deep infections

B. the dimorphic fungus Histoplasma capsulatum is a universal commensal on mucosal surfaces

C. the yeast Cryptococcus neoformans causes chronic meningo-encephalitis        

D. the yeast Pneumocystis jirovecii causes alveolitis in immuno-compromised people      

E. the yeast Candida albicans causes oesophagitis in AIDS

Answer 329

In humans      

A.  superficial fungal infections of hair or nails rarely cause disseminated deep infections (TRUE)

B. the dimorphic fungus Histoplasma capsulatum is a universal commensal on mucosal surfaces (FALSE)

C. the yeast Cryptococcus neoformans causes chronic meningo-encephalitis (TRUE)    

D. the yeast Pneumocystis jirovecii causes alveolitis in immuno-compromised people (TRUE)   

E. the yeast Candida albicans causes oesophagitis in AIDS (TRUE)

Question 330

The following statements are true

A. Candida albicans is a commensal organism in humans, a systemic opportunist and rarely causes deep infection        

B. Pneumocystis jirovecii commonly infects humans; reactivation is the     primary cause of Pneumocystis pneumonia 

C. the lung is the most frequent route of infection with fungal systemic pathogens          

D. α-1,3-glucans are recognized by Dectin-1

E. individuals deficient in Dectin-1 are susceptible to chronic nail infections

Answer 330

The following statements are true

A. Candida albicans is a commensal organism in humans, a systemic opportunist and rarely causes deep infection (TRUE)      

B. Pneumocystis jirovecii commonly infects humans; reactivation is the primary cause of Pneumocystis pneumonia (FALSE)

C. the lung is the most frequent route of infection with fungal systemic pathogens (TRUE)         

D. α-1,3-glucans are recognized by Dectin-1 (FALSE)

E. individuals deficient in Dectin-1 are susceptible to chronic nail infections (TRUE)

Question 331

With respect to fungal infections

A. Fungal glucan is recognized by the pattern recognition receptor Dectin-1         

B. Fungi lack nuclei and cytoplasmic organelles       

C. Invasive infection with Aspergillus fumigatus has high fatality    

D. Candida albicans is rarely found on human mucous membranes

E. Cryptococcus neoformans is abundant in bird droppings and causes progressive meningo-encephalitis           

Answer 331

With respect to fungal infections

A. Fungal glucan is recognized by the pattern recognition receptor Dectin-1 (TRUE)        

B. Fungi lack nuclei and cytoplasmic organelles (FALSE)

C. Invasive infection with Aspergillus fumigatus has high fatality (TRUE)

D. Candida albicans is rarely found on human mucous membranes (FALSE)

E. Cryptococcus neoformans is abundant in bird droppings and causes progressive meningo-encephalitis (TRUE)     

Question 332

The following statements regarding fungal infections are true        

A. Deficiency of interleukin IL-17 predisposes to superficial fungal infections        

B. Ergotamine is a potent vasoconstrictor    

C. Pneumocystis jirovecii infection is acquired by inhalation

D. Filamentous fungi are common components of the normal human flora           

E. TH17 but not TH1 cells help deal with fungal infections    

Answer 332

The following statements regarding fungal infections are true        

A. Deficiency of interleukin IL-17 predisposes to superficial fungal infections (TRUE)      

B. Ergotamine is a potent vasoconstrictor (TRUE)   

C. Pneumocystis jirovecii infection is acquired by inhalation (TRUE)

D. Filamentous fungi are common components of the normal human flora (FALSE)          

E. TH17 but not TH1 cells help deal with fungal infections (FALSE)

Question 333

Characteristic mammalian immune responses to worm infestations include

A. eosinophils            

B. IL-4 

C. IgE                          

D. antibody-dependent cell-mediated cytotoxicity (ADCC)                          

E. granuloma formation

Answer 333

Characteristic mammalian immune responses to worm infestations include

A. eosinophils (TRUE)      

B. IL-4 (TRUE)

C. IgE (TRUE)               

D. antibody-dependent cell-mediated cytotoxicity (ADCC) (TRUE)                     

E. granuloma formation (TRUE)

Question 334

The following statements about protozoan parasites are correct:                          

A. Infection with malaria engenders lifelong protection in adults                  

B. Leishmania parasites invade red blood cells                                             

C. Toxoplasma infection can arise from eating infected meat                       

D. African trypanosomes invade red blood cells                                           

E. Malaria parasites destroy red blood cells 

Answer 334

The following statements about protozoan parasites are correct:                          

A. Infection with malaria engenders lifelong protection in adults (FALSE)

B. Leishmania parasites invade red blood cells (FALSE)                                        

C. Toxoplasma infection can arise from eating infected meat (TRUE)

D. African trypanosomes invade red blood cells (FALSE)                                     

E. Malaria parasites destroy red blood cells (TRUE) 

Question 335

In malaria

A. erythrocyte destruction can lead to anaemia

B. fever is associated with synchronous parasite growth

C. cerebral complications are rarely fatal in children

D. acquired immunity usually affords life-long protection

E. the stage in the parasite life cycle that replicates within the mosquito is called the merozoite

Answer 335

In malaria

A. erythrocyte destruction can lead to anaemia (TRUE)

B. fever is associated with synchronous parasite growth (TRUE)

C. cerebral complications are rarely fatal in children (FALSE)

D. acquired immunity usually affords life-long protection (FALSE)

E. the stage in the parasite life cycle that replicates within the mosquito is called the merozoite (FALSE)

Question 336

Protozoan parasites

A. are always transmitted by an insect vector 

B. always invade host cells                            

C. are endoparasites                          

D. do not reproduce sexually  

E. are always eukaryotes        

Answer 336

Protozoan parasites

A. are always transmitted by an insect vector (FALSE)

B. always invade host cells (FALSE) 

C. are endoparasites (TRUE)                

D. do not reproduce sexually (FALSE)          

E. are always eukaryotes (TRUE)

Question 337

Parasitic helminths

A. may have both ‘direct’ and ‘indirect’ life cycles                           

B. generally do not replicate within the definitive host                                

C. generally elicit a TH2 immune response               

D. frequently cause chronic (long-term) infections  

E. include species that are transmitted by mosquitoes

Answer 337

Parasitic helminths

A. may have both ‘direct’ and ‘indirect’ life cycles (TRUE)                          

B. generally do not replicate within the definitive host (TRUE)                           

C. generally elicit a TH2 immune response (TRUE)        

D. frequently cause chronic (long-term) infections (TRUE)

E. include species that are transmitted by mosquitoes (TRUE)

Question 338

Human malaria

A. may be caused by four different species of the genus Plasmodium                                

B. causes a recurrent fever                            

C. may affect many different organs                                     

D. is transmitted by blackflies                       

E. may be responsible for the maintenance of thalassemias in human populations 

Answer 338

Human malaria

A. may be caused by four different species of the genus Plasmodium (TRUE)   

B. causes a recurrent fever (TRUE) 

C. may affect many different organs (TRUE)    

D. is transmitted by blackflies (FALSE) 

E. may be responsible for the maintenance of thalassemias in human populations (TRUE)

Question 339

Schistosoma mansoni

A. has a snail as an intermediate host                                               

B. in the human host, resides within the blood vessels of the bladder                                

C. is found principally in China                                  

D. adult worms directly cause major pathology in humans                         

E. generally lives for less than one year

Answer 339

Schistosoma mansoni

A. has a snail as an intermediate host (TRUE) 

B. in the human host, resides within the blood vessels of the bladder (FALSE)    

C. is found principally in China (FALSE)            

D. adult worms directly cause major pathology in humans (FALSE)             

E. generally lives for less than one year (FALSE)

Question 340

The following statements are true

A. Ascaris lumbricoides is a parasitic helminth  

B. Hookworms may cause significant blood loss

C. Apicomplexans are all protozoa  

D. The apical complex is required for active invasion of host cells  

E. Trypanosoma brucei gambiense causes sleeping sickness

Answer 340

The following statements are true 

A. Ascaris lumbricoides is a parasitic helminth (TRUE)

B. Hookworms may cause significant blood loss (TRUE) 

C. Apicomplexans are all protozoa (TRUE)    

D. The apical complex is required for active invasion of host cells (TRUE)                         

E. Trypanosoma brucei gambiense causes sleeping sickness (TRUE)

Question 341

Helminths

A. Are generally  transmitted by the faecal-oral route                                 

B. are generally intracellular                         

C. may sometimes be transmitted by insect vectors                        

D. can be killed by eosinophils                                  

E. are protozoans

Answer 341

Helminths

A. Are generally  transmitted by the faecal-oral route (TRUE)

B. are generally intracellular (FALSE) 

C. may sometimes be transmitted by insect vectors (TRUE)

D. can be killed by eosinophils

E. are protozoans (FALSE)

Question 342

The following statements about parasitic helminths are true                                  

A. Ascaris lumbricoides is transmitted by the faecal/oral route                   

B.  hookworms are transmitted by eating proglottids                                              

C. schistosomes are transmitted by blackflies                                              

D. blockage of blood vessels by adult worms causes the pathology seen in hepatosplenic schistosomiasis 

E. Individuals infected Trichuris trichuria may show few symptoms 

Answer 342

The following statements about parasitic helminths are true 

A. Ascaris lumbricoides is transmitted by the faecal/oral route (TRUE)

B.  hookworms are transmitted by eating proglottids (FALSE)

C. schistosomes are transmitted by blackflies (FALSE)

D. blockage of blood vessels by adult worms causes the pathology seen in hepatosplenic schistosomiasis (FALSE)          

E. Individuals infected Trichuris trichuria may show few symptoms (TRUE)

Question 343

Schistosomes

A. spend part of their life cycle in snails                                

B. reside in blood vessels of the liver or bladder                              

C. in humans, live within blood vessels                                             

D. are hermaphrodite                        

E. produce infective larvae called cercaria

Answer 343

Schistosomes

A. spend part of their life cycle in snails (TRUE)

B. reside in blood vessels of the liver or bladder (TRUE)

C. in humans, live within blood vessels (TRUE)

D. are hermaphrodite (FALSE)

E. produce infective larvae called cercaria (TRUE)

Question 344

Plasmodium falciparum                                 

A. destroys red blood cells                            

B. multiplies within its human host                           

C. is transmitted by the Aedes aegypti mosquito                             

D. sporozoites invade red blood cells                                   

E. can cause sequestration of red blood cells

Answer 344

Plasmodium falciparum                                 

A. destroys red blood cells (TRUE)

B. multiplies within its human host (TRUE)

C. is transmitted by the Aedes aegypti mosquito (FALSE)

D. sporozoites invade red blood cells (FALSE)

E. can cause sequestration of red blood cells (TRUE)

Question 345

The life cycles of the following parasites do not involve intermediate hosts                       

A. Ascaris lumbricoides                                 

B. Hookworms                       

C. Toxoplasma gondii                        

D. Plasmodium falciparum                

E. Schistosoma mansoni

Answer 345

The life cycles of the following parasites do not involve intermediate hosts                       

A. Ascaris lumbricoides (TRUE)                   

B. Hookworms (TRUE)              

C. Toxoplasma gondii (TRUE)                   

D. Plasmodium falciparum (FALSE)             

E. Schistosoma mansoni (FALSE)

Question 346

In malaria

A. only P. vivax sequesters and causes cerebral malaria                                          

B. P. falciparum modifies the surface of infected red blood cells                            

C. merozoites are released from infected red blood cells                                        

D. sequestration is limited to the brain of infected individuals                    

E. praziquantel offers good control

Answer 346

In malaria

A. only P. vivax sequesters and causes cerebral malaria (FALSE)

B. P. falciparum modifies the surface of infected red blood cells (TRUE)                      

C. merozoites are released from infected red blood cells (TRUE)

D. sequestration is limited to the brain of infected individuals (FALSE)

E. praziquantel offers good control (FALSE)

Question 347

Schistosome(s)

A. pair as juveniles in the liver and remain so for life                                   

B. infection is limited to primates                             

C. can survive for long periods in blood vessels                                

D. are surrounded by a tegument                                         

E. stimulate blocking IgG antibodies  

Answer 347

Schistosome(s)

A. pair as juveniles in the liver and remain so for life (TRUE)

B. infection is limited to primates (FALSE)

C. can survive for long periods in blood vessels (TRUE)

D. are surrounded by a tegument (TRUE)

E. stimulate blocking IgG antibodies (TRUE)  

Question 348

Members of the phylum Apicomplexa may   

A. be obligate intracellular parasites 

B. actively penetrate of host cells

C. have a kinetoplast                         

D. have an apicoplast                                    

E. have rhoptries

Answer 348

Members of the phylum Apicomplexa may  

A. be obligate intracellular parasites (TRUE) 

B. actively penetrate of host cells (TRUE)

C. have a kinetoplast (FALSE)

D. have an apicoplast (TRUE)                            

E. have rhoptries (TRUE)

Question 349

The following disease processes are caused primarily by immunopathological responses to the parasites indicated                                          

A. cerebral necrosis associated with Toxoplasma gondii infection                          

B.  portal hypertension associated with Schistosoma masoni infection                              

C. mucocutaneous lesions in Leishmania braziliensis infection                                

D. anaemia associated with Necator sp. infections                          

E.  Onchocerciasis due to tissue dwelling microfilariae of Onchocerca volvulus 

Answer 349

The following disease processes are caused primarily by immunopathological responses to the parasites indicated

A. cerebral necrosis associated with Toxoplasma gondii infection (FALSE)       

B.  portal hypertension associated with Schistosoma masoni infection (TRUE)

C. mucocutaneous lesions in Leishmania braziliensis infection (TRUE)

D. anaemia associated with Necator sp. infections (FALSE)                   

E.  Onchocerciasis due to tissue dwelling microfilariae of Onchocerca volvulus (TRUE)

Question 350

With regard to malaria

A. Sequestration of red cells infected by Plasmodium falciparum requires var gene expression                            

B. Sequestration of parasitized red cells is a pivotal process in the development of cerebral malaria

C. Metabolic acidosis is one of the symptoms of severe malaria and causes respiratory distress                          

D. P. vivax merozoites interact with the Duffy blood group antigens during invasion of red cells                          

E. The heterozygous sickle cell trait confers protection against severe P. falciparum malaria

Answer 350

With regard to malaria

A. Sequestration of red cells infected by Plasmodium falciparum requires var gene expression (TRUE)

B. Sequestration of parasitized red cells is a pivotal process in the development of cerebral malaria (TRUE)

C. Metabolic acidosis is one of the symptoms of severe malaria and causes respiratory distress (TRUE)

D. P. vivax merozoites interact with the Duffy blood group antigens during invasion of red cells (TRUE)

E. The heterozygous sickle cell trait confers protection against severe P. falciparum malaria (TRUE)

Question 351

The following statements are true

A. Ascaris lumbricoides is a nematode and lives within blood vessels of infected human hosts                

B. Ascaris lumbricoides infections are acquired following direct penetration of the skin by infective larvae                     

C. Female Ascaris lumbricoides commonly live for 15 years and release around 200,000 eggs per day     

D. Toxoplasma gondii undergoes sexual reproduction in gut epithelial  cells of cats, and oocysts are shed in faeces           

E. Praziquantel is the drug of choice for malarial infections

Answer 351

The following statements are true

A. Ascaris lumbricoides is a nematode and lives within blood vessels of infected human hosts (FALSE)

B. Ascaris lumbricoides infections are acquired following direct penetration of the skin by infective larvae (FALSE)

C. Female Ascaris lumbricoides commonly live for 15 years and release around 200,000 eggs per day (FALSE)

D. Toxoplasma gondii undergoes sexual reproduction in gut epithelial  cells of cats, and oocysts are shed in faeces (TRUE)

E. Praziquantel is the drug of choice for malarial infections (FALSE)

Question 352

Regarding schistosomiasis                                         

A. Adult worms of Schistosoma mansoni and S. japonicum live in blood vessels around the human gut                          

B. Miracidia are released from eggs and invade snails                                 

C. Granulomas containing large numbers of eosinophils form around parasite eggs          

D. Hepatic portal vein fibrosis and portal hypertension are symptoms of hepatosplenic disease                          

E. poor immune responses are associated with IgG4 production IgE production 

Answer 352

Regarding schistosomiasis

A. Adult worms of Schistosoma mansoni and S. japonicum live in blood vessels around the human gut (TRUE)

B. Miracidia are released from eggs and invade snails (TRUE)

C. Granulomas containing large numbers of eosinophils form around parasite eggs (TRUE)

D. Hepatic portal vein fibrosis and portal hypertension are symptoms of hepatosplenic disease (TRUE)

E. poor immune responses are associated with IgG4 production IgE production (TRUE)

Question 353

With respect to parasitic infections

A. Individuals infected with hookworm may lose as much as 200 ml of blood per day       

B. African sleeping sickness is spread by the tsese fly 

C. Onchocerca volvulus is a long thin filarial nematode transmitted by  black flies

D. Toxoplasma gondii is a parasitic protozoan and causes spontaneous abortion in sheep 

E. Helminths typically induce strong TH1 immune responses 

Answer 353

With respect to parasitic infections

A. Individuals infected with hookworm may lose as much as 200 ml of blood per day (TRUE)

B. African sleeping sickness is spread by the tsese fly (TRUE)

C. Onchocerca volvulus is a long thin filarial nematode transmitted by  black flies (TRUE)

D. Toxoplasma gondii is a parasitic protozoan and causes spontaneous abortion in sheep (TRUE)

E. Helminths typically induce strong TH1 immune responses (FALSE)

Question 354

The following statements regarding parasites are true                                            

A. A strong TH2 response is associated with the formation of large granulomas in Schistoma mansoni infections                                   

B. IL-10 production moderates the fibrosis that is associated with Schistoma mansoni infection                          

C. In Trypanosoma brucei, blood-stream-form trypanosomes are coated with variant surface glycoprotein (VSG) that protects against complementmediated lysis               

D. Schistoma mansoni infection intensisty is highest in adults                                

E. pfEMPs are the molecules responsible for sequestration of Plasmodium vivax infected red blood cells

Answer 354

The following statements regarding parasites are true                                            

A. A strong TH2 response is associated with the formation of large granulomas in Schistoma mansoni infections (TRUE)

B. IL-10 production moderates the fibrosis that is associated with Schistoma mansoni infection (FALSE)

C. In Trypanosoma brucei, blood-stream-form trypanosomes are coated with variant surface glycoprotein (VSG) that protects against complementmediated lysis (TRUE)

D. Schistoma mansoni infection intensisty is highest in adults (FALSE)

E. pfEMPs are the molecules responsible for sequestration of Plasmodium vivax infected red blood cells (FALSE)

Question 355

In parasitology

A. Blood-stream forms of Trypanosoma brucei have around 20 telomeric VSG expression sites 

B. chloroquine is a synthetic alkaloid related to quinine

C. The cercaria of human schistosomes live for 3-4 weeks and are attracted by human skin secretions 

D. Morbidity in schistosomiasis is almost entirely due to an immunopathological response to adult worms

E. Glycosylphosphatidyl inositol (GPI) functions as a membrane anchor for several P. falciparum merozoite surface proteins

Answer 355

In parasitology

A. Blood-stream forms of Trypanosoma brucei have around 20 telomeric VSG expression sites (TRUE)

B. chloroquine is a synthetic alkaloid related to quinine (TRUE)

C. The cercaria of human schistosomes live for 3-4 weeks and are attracted by human skin secretions (FALSE)

D. Morbidity in schistosomiasis is almost entirely due to an immunopathological response to adult worms (FALSE)

E. Glycosylphosphatidyl inositol (GPI) functions as a membrane anchor for several P. falciparum merozoite surface proteins (TRUE)

Question 356

Which of the following is least likely to be considered pro-thrombotic

A. microparticles

B. protein S

C. thromboxane A2

D. tissue factor

E. von Willebrand factor

Answer 356

Which of the following is least likely to be considered pro-thrombotic

A. microparticles (TRUE)

B. protein S (FALSE) 

C. thromboxane A2 (TRUE)

D. tissue factor (TRUE)

E. von Willebrand factor (TRUE)

Question 357

Which statement relating to a thrombus in the right ventricle is least accurate? It…

A. will initiate organisation (repair)

B. is unlikely to embolises to the brain

C. is often due to a myocardial infarction

D. can cause lung infarction

E. may embolise to the deep pelvic veins

Answer 357

Which statement relating to a thrombus in the right ventricle is least accurate? It…

A. will initiate organisation (repair) (TRUE)

B. is unlikely to embolises to the brain (TRUE)

C. is often due to a myocardial infarction (TRUE)

D. can cause lung infarction (TRUE)

E. may embolise to the deep pelvic veins (FALSE)

Question 358

Reactive oxygen species

A. are frequently generated during reperfusion of previously hypoxic tissues

B. are a normal product of cell metabolism

C. form part of the killing mechanism used by neutrophil polymorphonuclear leukocytes

D. damage cell membrane lipids

E. are activated by the cellular enzyme superoxide dismutase

Answer 358

Reactive oxygen species

A. are frequently generated during reperfusion of previously hypoxic tissues (TRUE)

B. are a normal product of cell metabolism (TRUE)

C. form part of the killing mechanism used by neutrophil polymorphonuclear leukocytes (TRUE)

D. damage cell membrane lipids (TRUE)

E. are activated by the cellular enzyme superoxide dismutase (FALSE)

Question 359

Which statement is least accurate. There is an increased risk of atherosclerosis in

A. diabetes mellitus

B. mice deficient for the native LDL receptor pathway

C. individuals with elevated levels of blood triglycerides

D. individuals with elevated levels of blood high-density lipoproteins

E. the elderly

Answer 359

Which statement is least accurate. There is an increased risk of atherosclerosis in

A. diabetes mellitus (TRUE)

B. mice deficient for the native LDL receptor pathway (TRUE)

C. individuals with elevated levels of blood triglycerides (TRUE)

D. individuals with elevated levels of blood high-density lipoproteins (FALSE)

E. the elderly (TRUE)

Question 360

Which statement is least accurate. In the development of an atherosclerotic plaque

A. endothelial cells are injured by oxidised lipoproteins

B. a local cell-mediated immune response may occur

C. smooth muscle cells secrete collagen

D. a high circulating HDL level is a positive risk factor

E. smooth muscle cells secrete collagenase

Answer 360

Which statement is least accurate. In the development of an atherosclerotic plaque

A. endothelial cells are injured by oxidised lipoproteins (TRUE)

B. a local cell-mediated immune response may occur (TRUE)

C. smooth muscle cells secrete collagen (TRUE)

D. a high circulating HDL level is a positive risk factor (FALSE)

E. smooth muscle cells secrete collagenase (TRUE)

Question 361

Which is the most accurate statement relating to ischaemia. It…

A. may follow a generalised type-1 hypersensitivity reaction

B. is less likely to occur in sickle cell anaemia

C. typically causes caseation necrosis

D. does not damage DNA

E. leads to death of skeletal muscle cells within 20 minutes

Answer 361

Which is the most accurate statement relating to ischaemia. It…

A. may follow a generalised type-1 hypersensitivity reaction (TRUE)

B. is less likely to occur in sickle cell anaemia (FALSE)

C. typically causes caseation necrosis (FALSE)

D. does not damage DNA (FALSE)

E. leads to death of skeletal muscle cells within 20 minutes (FALSE)

Question 362

Which statement relating to a myocardial infarct is the least accurate. It...

A. becomes pale and well demarcated within 24 hrs

B. may be accompanied by pericarditis

C. induces granulation tissue

D. may lead to rupture of the heart

E. may be due to thrombo-embolism from leg veins

Answer 362

Which statement relating to a myocardial infarct is the least accurate. It...

A. becomes pale and well demarcated within 24 hrs (TRUE)

B. may be accompanied by pericarditis (TRUE)

C. induces granulation tissue (TRUE)

D. may lead to rupture of the heart (TRUE)

E. may be due to thrombo-embolism from leg veins (FALSE)

Question 363

Atheroma is most poorly represented in which of the following?

A. it is initiated in the intima of arteries

B. it shows reduced prevalence in those with alcohol consumption of 2 units a day

C. it shows increased prevalence in association with diabetes mellitus

D. it forms at points where vessels branch

E. it is irreversible

Answer 363

Atheroma is most poorly represented in which of the following?

A. it is initiated in the intima of arteries (TRUE)

B. it shows reduced prevalence in those with alcohol consumption of 2 units a day (TRUE)

C. it shows increased prevalence in association with diabetes mellitus (TRUE)

D. it forms at points where vessels branch (TRUE)

E. it is irreversible (FALSE)

Question 364

Which of the following is the least accurate. Atheroma results in

A. aneurysm formation

B. clinically significant sequela in most large mammals

C. extracellular accumulation of lipid within the affected vessel wall

D. lymphocyte infiltration into the affected vessel wall

E. thrombus over the plaque

Answer 364

Which of the following is the least accurate. Atheroma results in

A. aneurysm formation (TRUE)

B. clinically significant sequela in most large mammals (FALSE)

C. extracellular accumulation of lipid within the affected vessel wall (TRUE)

D. lymphocyte infiltration into the affected vessel wall (TRUE)

E. thrombus over the plaque (TRUE)

Question 365

Which statement concerning thrombin generation is least accurate?

A. it is potentiated by lipoprotein

B. in “microparticles” it is inhibited by thrombomodulin

C. it is inhibited by protein C

D. it is required for generation of the primary haemostatic plug

E. it is stimulated by factor Xa

Answer 365

Which statement concerning thrombin generation is least accurate?

A. it is potentiated by lipoprotein (TRUE)

B. in “microparticles” it is inhibited by thrombomodulin (TRUE)

C. it is inhibited by protein C (TRUE)

D. it is required for generation of the primary haemostatic plug (FALSE)

E. it is stimulated by factor Xa (TRUE)

Question 366

Which of the following statements is most accurate?

A. “viscous metamorphosis” describes fusion of erythrocyte membranes

B. “foam cells” is a term applied to injured vascular endothelial cells

C. “oxidised LDL” is an alternative term for high density lipoprotein

D. ""scavenger receptors"" are responsible for uptake of oxidised LDL

E. pulmonary emboli do not arise through fragmentation of thrombi in veins of the lower limbs

Answer 366

Which of the following statements is most accurate?

A. “viscous metamorphosis” describes fusion of erythrocyte membranes (FALSE)

B. “foam cells” is a term applied to injured vascular endothelial cells (FALSE)

C. “oxidised LDL” is an alternative term for high density lipoprotein (FALSE)

D. ""scavenger receptors"" are responsible for uptake of oxidised LDL (TRUE)

E. pulmonary emboli do not arise through fragmentation of thrombi in veins of the lower limbs (FALSE)

Question 367

Haemostasis is promoted by

A. Epithelial damage

B. Nitric oxide

C. oxidised LDL

D. Inactivation of zymogens

E. Expression of von Willebrand factor

Answer 367

Haemostasis is promoted by

A. Epithelial damage (FALSE)

B. Nitric oxide (FALSE)

C. oxidised LDL (FALSE)

D. Inactivation of zymogens (FALSE)

E. Expression of von Willebrand factor (TRUE)

Question 368

Which statement regarding Ischaemia is LEAST accurate?

A. Can reduce the pH of tissues

B. Results in irreversible damage to heart muscle more rapidly than to skeletal muscle

C. Can occur in burns patients

D. Can occur following septic shock

E. Susceptibility is greater in organs with a collateral circulation

Answer 368

Which statement regarding Ischaemia is LEAST accurate?

A. Can reduce the pH of tissues (TRUE)

B. Results in irreversible damage to heart muscle more rapidly than to skeletal muscle (TRUE)

C. Can occur in burns patients (TRUE)

D. Can occur following septic shock (TRUE)

E. Susceptibility is greater in organs with a collateral circulation (FALSE)

Question 369

Which statement regarding a cerebral infarct is LEAST accurate?

A. May arise from an embolus from the aorta

B. May occur in patients with malaria

C. Typically illustrates caseous necrosis

D. Can produce a stroke

E. Is accompanied by capillary dilation

Answer 369

Which statement regarding a cerebral infarct is LEAST accurate?

A. May arise from an embolus from the aorta (TRUE)

B. May occur in patients with malaria (TRUE)

C. Typically illustrates caseous necrosis (FALSE)

D. Can produce a stroke (TRUE)

E. Is accompanied by capillary dilation (TRUE)

Question 370

Which statement regarding a thrombus in the left ventricle is LEAST likely. It may...

A. Lead to hypertrophy of the myocardium

B. Embolise to the lung

C. Arise following dysrhythmia

D. Be broken down using streptokinase

E. Initiate organisation (repair)

Answer 370

Which statement regarding a thrombus in the left ventricle is LEAST likely. It may...

A. Lead to hypertrophy of the myocardium (TRUE)

B. Embolise to the lung (FALSE)

C. Arise following dysrhythmia (TRUE)

D. Be broken down using streptokinase (TRUE)

E. Initiate organisation (repair) (TRUE)

Question 371

A complete return to normal tissue structure is a common result of which of the following?

A. liver cell regeneration following viral hepatitis

B. cardiac muscle regeneration following myocardial infarction

C. liver cell regeneration following a liver abscess

D. recovery from broncho pneumonia

E. healing of a cerebral infarct

Answer 371

A complete return to normal tissue structure is a common result of which of the following?

A. liver cell regeneration following viral hepatitis (TRUE)

B. cardiac muscle regeneration following myocardial infarction (FALSE)

C. liver cell regeneration following a liver abscess (FALSE)

D. recovery from broncho pneumonia (FALSE)

E. healing of a cerebral infarct (FALSE)

Question 372

The following are pro-thrombotic

A. prostacyclin

B. thrombomodulin

C. thromboplastin

D. protein C

E. macroparticles

Answer 372

The following are pro-thrombotic

A. prostacyclin (FALSE)

B. thrombomodulin (FALSE)

C. thromboplastin (TRUE)

D. protein C (FALSE)

E. macroparticles (FALSE)

Question 373

Which statement regarding a thrombus in the left atrium is LEAST accurate. It may…

A. be less common than a right atrium thrombus

B. be due to an abnormal cardiac rhythm

C. become infected

D. cause a myocardial infarct

E. be organised by repair

Answer 373

Which statement regarding a thrombus in the left atrium is LEAST accurate. It may…

A. be less common than a right atrium thrombus (FALSE)

B. be due to an abnormal cardiac rhythm (TRUE)

C. become infected (TRUE)

D. cause a myocardial infarct (TRUE)

E. be organised by repair (TRUE)

Question 374

There is an elevated risk of atherosclerosis in which one of the following?

A. post-menopausal women compared with pre-menopausal women

B. patients with reduced levels high-density lipoproteins in plasma

C. mice deficient for the scavenger receptor pathway

D. patients with hypertension

E. patients with elevated levels of blood triglycerides

Answer 374

There is an elevated risk of atherosclerosis in which one of the following?

A. post-menopausal women compared with pre-menopausal women (TRUE)

B. patients with reduced levels high-density lipoproteins in plasma (TRUE)

C. mice deficient for the scavenger receptor pathway (FALSE)

D. patients with hypertension (TRUE)

E. patients with elevated levels of blood triglycerides (TRUE)

Question 375

Which statement regarding atherosclerosis is most accurate. It …

A. is commonly found in the pulmonary arteries

B. is characterised by fibrosis of the media of the affected vessel

C. predisposes to venous thrombosis

D. predisposes to aortic aneurysm formation

E. develops in women at an earlier age than men

Answer 375

Which statement regarding atherosclerosis is most accurate. It …

A. is commonly found in the pulmonary arteries (FALSE)

B. is characterised by fibrosis of the media of the affected vessel (FALSE)

C. predisposes to venous thrombosis (FALSE)

D. predisposes to aortic aneurysm formation (TRUE)

E. develops in women at an earlier age than men (FALSE)

Question 376

The incidence in atherosclerosis is reduced in;

A. people with diabetes mellitus

B. people with familial hypercholesterolaemia

C. people with systemic hypertension

D. pre-menopausal women

E. people with terminal cancer

Answer 376

D. pre-menopausal women 

Question 377

Recognised sequelae of thrombosis include:-

A. lysis by plasmin

B. recanalisation

C. infarction in the tissue supplied by the blood vessel

D. development of collateral vessels

E. all of the above

Answer 377

Recognised sequelae of thrombosis include:-

A. lysis by plasmin (TRUE)

B. recanalisation (TRUE)

C. infarction in the tissue supplied by the blood vessel (TRUE)

D. development of collateral vessels (TRUE)

E. all of the above (TRUE)

Question 378

Which statement regarding ischaemia is LEAST accurate

A. can cause liquefactive necrosis

B. does not damage nucleic acids

C. is a complication of malaria

D. is tolerated better by skeletal muscle cells than by cardiac muscle cells

E. may follow severe infections with Gram-positive bacteria

Answer 378

B. does not damage nucleic acids

Question 379

Which is most likely regarding a lung infarction

A. it usually heals by regeneration

B. it is an example of a white infarct

C. it typically shows caseous necrosis

D. it commonly leads to left-sided heart failure

E. it is frequently accompanied by pleural inflammation

Answer 379

E. it is frequently accompanied by pleural inflammation

Question 380

What is UNLIKELY to happen after myocardial infarction

A. thrombosis tends to occur on the endocardial surface

B. chemotactic factors attract neutrophils to the edge of the necrotic area

C. activation of lysosomal enzymes facilitates digestion of cardiac muscle

D. muscle fibres close to the necrotic region become electrically hyperexcitable

E. the necrotic tissue is eventually replaced by regenerating myocytes

Answer 380

What is UNLIKELY to happen after myocardial infarction

A. thrombosis tends to occur on the endocardial surface (TRUE)

B. chemotactic factors attract neutrophils to the edge of the necrotic area (TRUE)

C. activation of lysosomal enzymes facilitates digestion of cardiac muscle (TRUE)

D. muscle fibres close to the necrotic region become electrically hyperexcitable (TRUE)

E. the necrotic tissue is eventually replaced by regenerating myocytes (FALSE)

Question 381

Which of the following is considered a definitive component of granulation tissue?

A. plasma cells

B. Fibrin-secreting cells

C. pus

D. proliferating endothelium

E. regenerating epithelium

Answer 381

D. proliferating endothelium

Question 382

Haemostasis is BEST promoted by

A. Prostacyclin

B. Nitric oxide

C. Thrombomodulin

D. Inactivation of zymogens

E. Expression of von Willebrand factor

Answer 382

E. Expression of von Willebrand factor

Question 383

Which statement is MOST accurate. Ischaemia…

A. Can increase the pH of tissues

B. Results in irreversible damage to heart muscle more slowly than to skeletal muscle

C. Can occur in burns patients

D. rarely occurs following septic shock

E. Susceptibility is higher in organs with a collateral circulation

Answer 383

C. Can occur in burns patients

Question 384

Which statement is LEAST accurate. A thrombus in the left ventricle may

A. lead to hypertrophy of the myocardium

B. not embolise to the kidney

C. arise following dysrhythmia

D. be broken down using streptokinase

E. initiate organisation (repair)

Answer 384

Which statement is LEAST accurate. A thrombus in the left ventricle may

A. lead to hypertrophy of the myocardium (TRUE)

B. not embolise to the kidney (FALSE)

C. arise following dysrhythmia (TRUE)

D. be broken down using streptokinase (TRUE)

E. initiate organisation (repair) (TRUE)

Question 385

Which statement is LEAST accurate in relation to a cerebral infarct.

A. it may arise from an embolus from the aorta

B. it may occur in patients with malaria

C. it typically illustrates caseous necrosis

D. it can produce a stroke

E. it is accompanied by capillary dilation

Answer 385

Which statement is LEAST accurate in relation to a cerebral infarct.

A. it may arise from an embolus from the aorta (TRUE)

B. it may occur in patients with malaria (TRUE)

C. it typically illustrates caseous necrosis (FALSE)

D. it can produce a stroke (TRUE)

E. it is accompanied by capillary dilation (TRUE)

Question 386

Apoptosis differs from necrosis in a number of ways. Which statement least accurately reflects properties of apoptosis?

A. phagocytosis of fragments of dying cells occurs in necrosis but seldom in apoptosis     

B. necrosis characteristically involves sheets of cells whilst apoptosis usually affects single cells

C. apoptosis seldom excites local neutrophil infiltration, but this frequently accompanies necrosis

D. the proteolysis that is initiated in apoptosis, unlike that of necrosis, tends to occur at specific intramolecular sites   

E. apoptosis, unlike necrosis, is the mode of death usually adopted during development 

Answer 386

Apoptosis differs from necrosis in a number of ways. Which statement least accurately reflects properties of apoptosis?

A. phagocytosis of fragments of dying cells occurs in necrosis but seldom in apoptosis (FALSE)     

B. necrosis characteristically involves sheets of cells whilst apoptosis usually affects single cells (TRUE)

C. apoptosis seldom excites local neutrophil infiltration, but this frequently accompanies necrosis (TRUE)

D. the proteolysis that is initiated in apoptosis, unlike that of necrosis, tends to occur at specific intramolecular sites (TRUE)

E. apoptosis, unlike necrosis, is the mode of death usually adopted during development (TRUE)

Question 387

Which of the following molecules are not pro-apoptotic?   

A. caspase 3   

B. cytochrome c         

C. BAX

D. PTEN          

E. AKT  

Answer 387

Which of the following molecules are not pro-apoptotic?   

A. caspase 3 (TRUE)

B. cytochrome c (TRUE)      

C. BAX (TRUE)

D. PTEN (TRUE)       

E. AKT (FALSE)

Question 388

Which statement relating to reactive oxygen species is least accurate? Reactive oxygen species…           

A. are frequently generated during reperfusion of previously hypoxic tissues        

B. are activated by intracellular glutathione 

C. form part of the killing mechanism used by neutrophil polymorphonuclear leukocytes

D. damage cell membrane lipids       

E. are inactivated by the cellular enzyme superoxide dismutase

Answer 388

Which statement relating to reactive oxygen species is least accurate? Reactive oxygen species…           

A. are frequently generated during reperfusion of previously hypoxic tissues (TRUE)

B. are activated by intracellular glutathione (FALSE)

C. form part of the killing mechanism used by neutrophil polymorphonuclear leukocytes (TRUE)

D. damage cell membrane lipids (TRUE)    

E. are inactivated by the cellular enzyme superoxide dismutase (TRUE)

Question 389

Which statement relating to Bcl-2 is least accurate? The bcl-2 gene..         

A. encodes an tumour suppressor protein   

B. is involved in a chromosomal translocation insome lymphomas 

C. encodes a cell survival factor        

D. is an oncogene      

E. is a member of a gene family that encodes both pro-survival and pro-death factors

Answer 389

Which statement relating to Bcl-2 is least accurate? The bcl-2 gene..         

A. encodes an tumour suppressor protein (FALSE)   

B. is involved in a chromosomal translocation insome lymphomas (TRUE)

C. encodes a cell survival factor (TRUE)       

D. is an oncogene  (TRUE)   

E. is a member of a gene family that encodes both pro-survival and pro-death factors (TRUE)

Question 390

Which of the following mechanisms of carcinogenesis has not been observed in common human tumours  A. activating point mutations involving the K-RAS gene   B. inactivating mutations of PTEN C. amplification at the MYC and CYCLIN D1 loci        D. truncating mutation of the APC gene   E. chromosome translocation leading to fusion of BCL-2 and ABL

Answer 390

Which of the following mechanisms of carcinogenesis has not been observed in common human tumours    A. activating point mutations involving the K-RAS gene (TRUE) B. inactivating mutations of PTEN (TRUE) C. amplification at the MYC and CYCLIN D1 loci (TRUE) D. truncating mutation of the APC gene (TRUE)  E. chromosome translocation leading to fusion of BCL-2 and ABL (FALSE)

Question 391

Which of the following definitions is given both adequately and correctly 

A. an adenocarcinoma is a benign tumour arising from glandular epithelium        

B. hypertrophy refers to an increase in the number of cells in a tissue       

C. metaplasia describes the spectrum of morphological changes that often lead to neoplasia, associated with disorganisation of cellular pattern, variability in cell size and shape, and nuclear hyperchromatism     

D. a haematoma is a tumour of blood vessels          

E. a chondroma is a benign tumour of cartilage

Answer 391

Which of the following definitions is given both adequately and correctly 

A. an adenocarcinoma is a benign tumour arising from glandular epithelium (FALSE)

B. hypertrophy refers to an increase in the number of cells in a tissue (FALSE)

C. metaplasia describes the spectrum of morphological changes that often lead to neoplasia, associated with disorganisation of cellular pattern, variability in cell size and shape, and nuclear hyperchromatism (FALSE)

D. a haematoma is a tumour of blood vessels (FALSE)  

E. a chondroma is a benign tumour of cartilage (TRUE)

Question 392

Infection with which of the following agents is least likely to be associated with increased susceptibility to malignant diseases

A. Epstein Barr virus  

B. Helicobacter pylori

C. HPV type 16

D. Schistosoma mansoni       

E. Marek’s Disease virus

Answer 392

Infection with which of the following agents is least likely to be associated with increased susceptibility to malignant diseases

A. Epstein Barr virus (TRUE)  

B. Helicobacter pylori (TRUE)

C. HPV type 16 (TRUE)

D. Schistosoma mansoni (FALSE)

E. Marek’s Disease virus (TRUE)

Question 393

Which statement relating to inactivation or loss of a tumour suppressor allele is most accurate?

A. is inherited in all cases of retinoblastoma

B. always requires mutation of both copies of the gene      

C. if inherited, can confer increased risk of tumour development at atypically early age   

D. may occur by methylation mRNA 5' untranslated egions

E. can only be detected by DNA sequencing  

Answer 393

Which statement relating to inactivation or loss of a tumour suppressor allele is most accurate?

A. is inherited in all cases of retinoblastoma (FALSE)

B. always requires mutation of both copies of the gene (FALSE)    

C. if inherited, can confer increased risk of tumour development at atypically early age (TRUE)

D. may occur by methylation mRNA 5' untranslated egions (FALSE)

E. can only be detected by DNA sequencing (FALSE) 

Question 394

Which of the following statements is most accurate?          

A. carcinogenic K-RAS mutations usually destroy the GTP binding capacity of the oncoprotein    

B. myc oncoproteins are located predominantly on the cell membrane     

C. many proto-oncogenes encode tyrosine kinases 

D. all known cellular oncogenes have retroviral homologues          

E. the adenomatous polposis coli (APC. protein participates in activation of  b-catenin      

Answer 394

Which of the following statements is most accurate?          

A. carcinogenic K-RAS mutations usually destroy the GTP binding capacity of the oncoprotein (FALSE)   

B. myc oncoproteins are located predominantly on the cell membrane (FALSE)

C. many proto-oncogenes encode tyrosine kinases (TRUE)

D. all known cellular oncogenes have retroviral homologues (FALSE)

E. the adenomatous polposis coli (APC. protein participates in activation of  b-catenin (FALSE)

Question 395

In relation to human tumours which statement is most accurate? 

A. fusion of TMPRSS2 and ERG is rarely seen in prostate cancer     

B. RAS and B-RAF  mutations appear to have similar effects in cells

C. we know precisely how many mutations are required to cause cancer  

D. Errors in mismatch repair are are considered promoter rather than initiator events     

E. Both alleles of p53 must be altered to produce a phenotype

Answer 395

In relation to human tumours which statement is most accurate? 

A. fusion of TMPRSS2 and ERG is rarely seen in prostate cancer (FALSE)   

B. RAS and B-RAF  mutations appear to have similar effects in cells (TRUE)

C. we know precisely how many mutations are required to cause cancer (FALSE)

D. Errors in mismatch repair are are considered promoter rather than initiator events (FALSE)   

E. Both alleles of p53 must be altered to produce a phenotype (FALSE)

Question 396

There is little evidence that one of the following is carcinogenic in man.   

A. infra-red radiation 

B. ultraviolet radiation           

C. food additives        

D. aflatoxin    

E. asbestos

Answer 396

There is little evidence that one of the following is carcinogenic in man.   

A. infra-red radiation (FALSE)

B. ultraviolet radiation (TRUE)        

C. food additives (FALSE)     

D. aflatoxin (TRUE)

E. asbestos (TRUE)

Question 397

Which of the following statements most accurately represent correct usage of terminology

A. dysplasia implies replacement of a normal differentiated cell type by another inappropriate to the site         

B. aneuploidy implies deficiency in cellular differentiaion   

C. aneuploidy and genomic instability are terms with the same meaning when applied to malignant tumours    

D. tumours do not  not have to have formed metastases to be called malignant   

E. intra-epithelial neoplasia implies the existence of a malignant but non-invasive tumour

Answer 397

Which of the following statements most accurately represent correct usage of terminology

A. dysplasia implies replacement of a normal differentiated cell type by another inappropriate to the site (FALSE)    

B. aneuploidy implies deficiency in cellular differentiaion (FALSE)    

C. aneuploidy and genomic instability are terms with the same meaning when applied to malignant tumours  (FALSE)

D. tumours do not  not have to have formed metastases to be called malignant (TRUE)

E. intra-epithelial neoplasia implies the existence of a malignant but non-invasive tumour (FALSE)

Question 398

The following is least likely to be considered a malignant tumours 

A. Adenoma   

B. sarcoma     

C. melanoma  

D. lymphoma 

E. seminoma

Answer 398

The following is least likely to be considered a malignant tumours

A. Adenoma (FALSE)

B. sarcoma (TRUE)

C. melanoma (TRUE)

D. lymphoma (TRUE)

E. seminoma (TRUE)

Question 399

Which statement relating to carcinogenesis is least accurate?        

A. The action of promotors fades with time 

B. Promotors alone can cause cancer

C. The effects of initiation are irreversible    

D. There is a linear relationship between the dose of carcinogen (delivered in a single dose) and the number of tumours developing  

E. Ultraviolet light induces formation of pyrimidine dimers

Answer 399

Which statement relating to carcinogenesis is least accurate?        

A. The action of promotors fades with time (TRUE)

B. Promotors alone can cause cancer (FALSE)

C. The effects of initiation are irreversible (TRUE)

D. There is a linear relationship between the dose of carcinogen (delivered in a single dose) and the number of tumours developing (TRUE)

E. Ultraviolet light induces formation of pyrimidine dimers (TRUE)

Question 400

Which statement relating to causes of cancer is most accurate?    

A. tobacco smoke causes at least 60% of cancer in the UK  

B. the most potent carcinogens in man are synthetic          

C. the incidence of breast cancer is lower in women who have children at an early age    

D. most chemical carcinogens are naturally highly reactive against DNA    

E. UV light attacks purine bases

Answer 400

Which statement relating to causes of cancer is most accurate?    

A. tobacco smoke causes at least 60% of cancer in the UK (FALSE)

B. the most potent carcinogens in man are synthetic (FALSE)

C. the incidence of breast cancer is lower in women who have children at an early age (TRUE)   

D. most chemical carcinogens are naturally highly reactive against DNA (FALSE)

E. UV light attacks purine bases (FALSE)

Question 401

Which of the following would most likely inhibit cellular progression around the cell replication cycle?  

A. phosphorylated Rb

B. p16INK4A   

C. BRCA2        

D. AKT

E. cdk4

Answer 401

Which of the following would most likely inhibit cellular progression around the cell replication cycle?  

A. phosphorylated Rb (FALSE)

B. p16INK4A (TRUE)

C. BRCA2 (FALSE)   

D. AKT (FALSE)

E. cdk4 (FALSE)

Question 402

Which of the following is least likely to show recognised association with human cancers:-

A. human papillomavirus type 18     

B. Schistosoma mansoni        

C. Epstein-Barr virus  

D. Helicobacter pylori

E. hepatitis B virus

Answer 402

Which of the following is least likely to show recognised association with human cancers:-

A. human papillomavirus type 18 (TRUE)

B. Schistosoma mansoni (FALSE)       

C. Epstein-Barr virus (TRUE)

D. Helicobacter pylori (TRUE)

E. hepatitis B virus (TRUE)

Question 403

Both activation of oncogenes and inactivation of tumour suppressor genes is least likely to occur in which situation?   

A. can occur in the same tumour cell

B. can occur in the same signalling pathway

C. can occur in the same gene           

D. can occur by point mutation         

E. can occur in hereditary predisposition to cancer

Answer 403

Both activation of oncogenes and inactivation of tumour suppressor genes is least likely to occur in which situation?   

A. can occur in the same tumour cell (TRUE)

B. can occur in the same signalling pathway (TRUE)

C. can occur in the same gene (FALSE)          

D. can occur by point mutation (TRUE)       

E. can occur in hereditary predisposition to cancer (TRUE)

Question 404

Which statement regarding the Wnt signalling pathway is incorrect?         

A. lack of signalling through the wnt receptor results in phosphorylation of b-catenin      

B. TCF4 is considered an oncogene   

C. APC forms part of a complex required for gsk3 to phosphorylate b-catenin       

D. the wnt receptor responds to a variety of growth inhibiting glycoproteins 

E. almost all colorectal cancers have mutations in wnt signalling, most commonly defects in APC

Answer 404

Which statement regarding the Wnt signalling pathway is incorrect?         

A. lack of signalling through the wnt receptor results in phosphorylation of b-catenin (TRUE)

B. TCF4 is considered an oncogene (TRUE)

C. APC forms part of a complex required for gsk3 to phosphorylate b-catenin (TRUE)  

D. the wnt receptor responds to a variety of growth inhibiting glycoproteins (FALSE)

E. almost all colorectal cancers have mutations in wnt signalling, most commonly defects in APC (TRUE)

Question 405

Which statement regarding p53 is most accurate. p53 …    

A. can sense telomere lengthening   

B. normally has a long half life in cells          

C. can act as a transcription factor that induces expression of p21CIP        

D. activates cyclin/cdk activity          

E. binds E2F and blocks transcription

Answer 405

Which statement regarding p53 is most accurate. p53 

A. can sense telomere lengthening (FALSE) B. normally has a long half life in cells (FALSE)      C. can act as a transcription factor that induces expression of p21CIP (TRUE)   D. activates cyclin/cdk activity (FALSE)       

E. binds E2F and blocks transcription (FALSE)

Question 406

Which of the following statements is least accurate?          

A. TGF-beta signalling is inhibitory    

B. PTEN is a kinase     

C. BRCA1 and BRCA2 are unrelated molecules involved in DNA repair        

D. the EGF receptor HER2 is a target for Herceptin  

E. BRAF is an oncogene        

Answer 406

Which of the following statements is least accurate?          

A. TGF-beta signalling is inhibitory (TRUE)

B. PTEN is a kinase (FALSE)

C. BRCA1 and BRCA2 are unrelated molecules involved in DNA repair (TRUE)       

D. the EGF receptor HER2 is a target for Herceptin (TRUE)   

E. BRAF is an oncogene (TRUE)       

Question 407

Regarding the following cancers which of the statements is least accurate?          

A. About 40% of retinoblastoma cases are hereditary

B. hereditary predisposition to breast cancer shows high penetrance        

C. Familial Adenomatous Polyposis Coli is rare affecting 1/10,000 individuals        

D. mutations in the apc gene are not seen in sporadic colorectal cases      

E. Hereditary Non-Polyposis Colon Cancer is associated with mutations in DNA repair genes

Answer 407

Regarding the following cancers which of the statements is least accurate?          

A. About 40% of retinoblastoma cases are hereditary (TRUE)

B. hereditary predisposition to breast cancer shows high penetrance (TRUE)

C. Familial Adenomatous Polyposis Coli is rare affecting 1/10,000 individuals (TRUE)    

D. mutations in the apc gene are not seen in sporadic colorectal cases (FALSE)

E. Hereditary Non-Polyposis Colon Cancer is associated with mutations in DNA repair genes (TRUE)

Question 408

Which of the following statements relating to the immune system and cancer is least accurate?  The immune system     

A. is significantly associated with control of certain types of neoplasm      

B. is regulated by inhibitory signals delivered by molecules such as such as PD-1 and CTLA-4

C. is compromised in chemotherapy for cancer       

D. has been proven to be involved in cancer control through tumour graft rejection experiments

E. can be induced to attack tumours

Answer 408

Which of the following statements relating to the immune system and cancer is least accurate?  The immune system       

A. is significantly associated with control of certain types of neoplasm (TRUE)

B. is regulated by inhibitory signals delivered by molecules such as such as PD-1 and CTLA-4 (TRUE)

C. is compromised in chemotherapy for cancer (TRUE)      

D. has been proven to be involved in cancer control through tumour graft rejection experiments (FALSE)

E. can be induced to attack tumours (TRUE)

Question 409

Which of the following molecules is least likely to be considered an activator of apoptosis

A. caspase 8   

B. heat shock proteins           

C. ATM and ATR         

D. TNF (tumour necrosis factor)        

E. BAX  

Answer 409

Which of the following molecules is least likely to be considered an activator of apoptosis

A. caspase 8 (TRUE)

B. heat shock proteins (FALSE)       

C. ATM and ATR (TRUE)

D. TNF (TRUE)   

E. BAX (TRUE)

Question 410

Which statement concerning apoptotic cells is incorrect?  Apoptotic cells

A. may be found in normal adult tissues       

B. are found in normal embryonic tissues    

C. are usually present in the follicle centres of reactive lymph nodes         

D. may result from tissue injury        

E. are usually absent from malignant tumours

Answer 410

Which statement concerning apoptotic cells is incorrect?  Apoptotic cells     

A. may be found in normal adult tissues (TRUE)    

B. are found in normal embryonic tissues (TRUE)  

C. are usually present in the follicle centres of reactive lymph nodes (TRUE)

D. may result from tissue injury (TRUE)    

E. are usually absent from malignant tumours (FALSE)

Question 411

Which of the following is not a well documented association?       

A. gonococcal infection, epididymitis and testicular teratoma        

B. papillomavirus infection, anal carcinoma and AIDS          

C. b-naphthylamine and bladder cancer       

D. Schistosoma haematobium and bladder cancer  

E. Aflatoxin, hepatitis B virus and hepatocellular carcinoma

Answer 411

Which of the following is not a well documented association?       

A. gonococcal infection, epididymitis and testicular teratoma (FALSE)      

B. papillomavirus infection, anal carcinoma and AIDS (TRUE)         

C. b-naphthylamine and bladder cancer (TRUE)     

D. Schistosoma haematobium and bladder cancer (TRUE)

E. Aflatoxin, hepatitis B virus and hepatocellular carcinoma (TRUE)

Question 412

Which of the following statements concerning tumours is most accurate?

A. Leukaemias are neoplasms

B. Leiomyoma of the uterus often shows metaplasia           

C. Adenocarcinoma of the uterine cervix often develops from squamous metaplasia.      

D. Sarcomas are not always malignant         

E. Carcinomas rarely show dysplasia  

Answer 412

Which of the following statements concerning tumours is most accurate?

A. Leukaemias are neoplasms (TRUE)

B. Leiomyoma of the uterus often shows metaplasia (FALSE)    

C. Adenocarcinoma of the uterine cervix often develops from squamous metaplasia. (FALSE)

D. Sarcomas are not always malignant (FALSE)

E. Carcinomas rarely show dysplasia (FALSE)

Question 413

Which statement is most accurate. Mismatch repair deficiency, also known as microsatellite instability 

A. Is a characteristic of 10 to 20% of breast cancers

B. Substantially increases the rate of chromosome translocation   

C. Is associated with benign rather than malignant tumours in the colon   

D. Is the defect in Lynch Syndrome / HNPCC

E. In colon cancer, usually leads to TNF-alpha Receptor II mutations

Answer 413

Which statement is most accurate. Mismatch repair deficiency, also known as microsatellite instability 

A. Is a characteristic of 10 to 20% of breast cancers (FALSE)

B. Substantially increases the rate of chromosome translocation (FALSE)

C. Is associated with benign rather than malignant tumours in the colon (FALSE)

D. Is the defect in Lynch Syndrome / HNPCC (TRUE)

E. In colon cancer, usually leads to TNF-alpha Receptor II mutations (FALSE)

Question 414

Which statement is most accurate. The BCR-ABL gene fusion product …    

A. Occurs in myeloid leukaemia        

B. Is formed by a chromosome inversion      

C. Is often associated with Epstein Barr virus infection        

D. Trimerises spontaneously 

E. Activates the phosphatase of the Abl protein

Answer 414

Which statement is most accurate. The BCR-ABL gene fusion product …    

A. Occurs in myeloid leukaemia (TRUE)    

B. Is formed by a chromosome inversion (FALSE)

C. Is often associated with Epstein Barr virus infection (FALSE)

D. Trimerises spontaneously (FALSE)

E. Activates the phosphatase of the Abl protei (FALSE)

Question 415

Which statement is least accurate. The metabolic activation of chemical carcinogens      

A. Is required for aromatic hydrocarbons to react with DNA           

B. Often involves the cytochrome P450 oxidases     

C. Contributes to tissue specificity    

D. Complicates in vitro testing for carcinogens        

E. Is unnecessary for natural carcinogens such as aflatoxins

Answer 415

Which statement is least accurate. The metabolic activation of chemical carcinogens      

A. Is required for aromatic hydrocarbons to react with DNA (TRUE)            

B. Often involves the cytochrome P450 oxidases (TRUE)

C. Contributes to tissue specificity (TRUE)

D. Complicates in vitro testing for carcinogens (TRUE)  

E. Is unnecessary for natural carcinogens such as aflatoxins (FALSE)

Question 416

According to our current knowledge of genetic instability which statement is most accurate?

A. Colorectal cancers usually show both microsatellite instability and chromosome instability

B. Chromosome instability may be caused by errors in mitosis       

C. Chromosome instability is not caused by BRCA2 mutations        

D. Microsatellite instability is caused by defective excision repair   

E. Is unnecessary for natural carcinogens such as aflatoxins

Answer 416

According to our current knowledge of genetic instability which statement is most accurate?

A. Colorectal cancers usually show both microsatellite instability and chromosome instability (FALSE)

B. Chromosome instability may be caused by errors in mitosis (TRUE)

C. Chromosome instability is not caused by BRCA2 mutations (FALSE)

D. Microsatellite instability is caused by defective excision repair (FALSE)

E. Is unnecessary for natural carcinogens such as aflatoxins (FALSE)

Question 417

Which statement concerning mutations in human cancer is least accurate?          

A. The term ‘Amplification’ refers to abnormal promoter activity   

B. Deletion of a gene can create gene fusions          

C. The TMPRSS2-ERG fusion is common in prostate cancer 

D. BRAF mutations are often located near to an activating phosphorylation site   

E. Frameshift mutations usually cause protein truncation

Answer 417

Which statement concerning mutations in human cancer is least accurate?          

A. The term ‘Amplification’ refers to abnormal promoter activity (FALSE)

B. Deletion of a gene can create gene fusions (TRUE) 

C. The TMPRSS2-ERG fusion is common in prostate cancer (TRUE) 

D. BRAF mutations are often located near to an activating phosphorylation site (TRUE)   

E. Frameshift mutations usually cause protein truncation (TRUE) 

Question 418

Which statement concerning metastasis is most accurate?

A. Malignant squamous epithelial cells do not grow in lymph nodes          

B. Normal cells cannot exit the circulation   

C. Malignant cells can disseminate via both lymphatics and capillaries       

D. In transplantation experiments, metastases grow better than primary tumours

E. Most cancer cells that enter the circulation form metastases     

Answer 418

Which statement concerning metastasis is most accurate?

A. Malignant squamous epithelial cells do not grow in lymph nodes (FALSE)        

B. Normal cells cannot exit the circulation (FALSE)

C. Malignant cells can disseminate via both lymphatics and capillaries (TRUE)      

D. In transplantation experiments, metastases grow better than primary tumours (FALSE)

E. Most cancer cells that enter the circulation form metastases (FALSE)

Question 419

With respect to strong hereditary predispositions to cancer which statement is least accurate?  

A. Some are more prevalent than cystic fibrosis      

B. MHL-1 mutations predispose to breast cancer     

C. Several are defects in DNA repair 

D. They typically involve inheritance of a tumour suppressor gene mutation         

E. They made possible the discovery of APC, RB1, and BRCA2

Answer 419

With respect to strong hereditary predispositions to cancer which statement is least accurate?  

A. Some are more prevalent than cystic fibrosis (TRUE)

B. MHL-1 mutations predispose to breast cancer (FALSE)

C. Several are defects in DNA repair (TRUE) 

D. They typically involve inheritance of a tumour suppressor gene mutation (TRUE) 

E. They made possible the discovery of APC, RB1, and BRCA2 (TRUE) 

Question 420

Which statement concerning tumours is most accurate?     A. Leukaemias are neoplasms B. Leiomyoma of the uterus often shows metaplasia  C. Adenocarcinoma of the uterine cervix often develops from squamous metaplasia. D. Sarcomas are not always malignant E. Carcinomas rarely show dysplasia  

Answer 420

Which statement concerning tumours is most accurate?   A. Leukaemias are neoplasms (TRUE)  B. Leiomyoma of the uterus often shows metaplasia (FALSE) C. Adenocarcinoma of the uterine cervix often develops from squamous metaplasia.  (FALSE)    D. Sarcomas are not always malignant (FALSE)      E. Carcinomas rarely show dysplasia (FALSE)

Question 421

Mismatch repair deficiency, also known as microsatellite instability is most accurately described in which of the follow

A. Is a characteristic of 10 to 20% of breast cancers

B. Substantially increases the rate of chromosome translocation

C. Is associated with benign rather than malignant tumours in the colon               

D. Is the defect in Lynch Syndrome / HNPCC

E. Involves BRCA1 and BRCA2

Answer 421

Mismatch repair deficiency, also known as microsatellite instability is most accurately described in which of the follow

A. Is a characteristic of 10 to 20% of breast cancers (FALSE)

B. Substantially increases the rate of chromosome translocation (FALSE)

C. Is associated with benign rather than malignant tumours in the colon (FALSE)

D. Is the defect in Lynch Syndrome / HNPCC (TRUE) 

E. Involves BRCA1 and BRCA2 (FALSE)

Question 422

Which most accurately describes a feature of the BCR-ABL gene fusion product? 

A. Occurs in myeloid leukaemia        

B. Is formed by a chromosome inversion      

C. Is often associated with Epstein Barr virus infection        

D. It acts as a transcription factor     

E. Activates the phosphatase of the Abl protein

Answer 422

Which most accurately describes a feature of the BCR-ABL gene fusion product? 

A. Occurs in myeloid leukaemia (TRUE)       

B. Is formed by a chromosome inversion (FALSE)    

C. Is often associated with Epstein Barr virus infection (FALSE)     

D. It acts as a transcription factor (FALSE)     

E. Activates the phosphatase of the Abl protein (FALSE)

Question 423

Which of the following is least accurate?  Metabolic activation of chemical carcinogens …

A. Is required for aromatic hydrocarbons to react with DNA           

B. Often involves the cytochrome P450 oxidases     

C. Contributes to tissue specificity    

D. Complicates in vitro testing for carcinogens        

E. Is unnecessary for natural carcinogens such as aflatoxins

Answer 423

Which of the following is least accurate?  Metabolic activation of chemical carcinogens …

A. Is required for aromatic hydrocarbons to react with DNA (TRUE)         

B. Often involves the cytochrome P450 oxidases (TRUE)    

C. Contributes to tissue specificity (TRUE)    

D. Complicates in vitro testing for carcinogens (TRUE)          

E. Is unnecessary for natural carcinogens such as aflatoxins (FALSE)

Question 424

Viruses that cause zoonotic infections

A. include measles virus

B. cause diseases with high mortality/morbidity

C. include influenza virus

D. may be transmitted by insects

E. have non-humans as natural hosts

Answer 424

Viruses that cause zoonotic infections

A. include measles virus (FALSE)

B. cause diseases with high mortality/morbidity (TRUE)

C. include influenza virus (TRUE)

D. may be transmitted by insects (TRUE)

E. have non-humans as natural hosts (TRUE)

Question 425

The group ‘reversiviruses’ includes

A. feline leukaemia virus

B. variola virus

C. hepatitis C virus

D. Rous sarcoma virus

E. hepatitis B virus

Answer 425

The group ‘reversiviruses’ includes

A. feline leukaemia virus (TRUE)

B. variola virus (FALSE)

C. hepatitis C virus (FALSE)

D. Rous sarcoma virus (TRUE)

E. hepatitis B virus (FALSE)

Question 426

Interferon beta

A. is induced by activated Toll-like receptors

B. induces the expression of interferon stimulated genes (ISGs) via NFkB

C. is a glycosylated protein

D. directly binds viruses and blocks entry

E. up-regulates class I MHC

Answer 426

Interferon beta

A. is induced by activated Toll-like receptors (TRUE)

B. induces the expression of interferon stimulated genes (ISGs) via NFkB (FALSE)

C. is a glycosylated protein (TRUE)

D. directly binds viruses and blocks entry (FALSE)

E. up-regulates class I MHC (TRUE)

Question 427

Yellow fever virus

A. is a zoonotic infection

B. is commonly transmitted by mosquitoes

C. causes a respiratory infection

D. infects most mammals

E. can have high mortality rates

Answer 427

Yellow fever virus

A. is a zoonotic infection (TRUE)

B. is commonly transmitted by mosquitoes (TRUE)

C. causes a respiratory infection (FALSE)

D. infects most mammals (FALSE)

E. can have high mortality rates (TRUE)

Question 428

Influenza virus

A. replicates in the cytoplasm

B. encodes an ion channel protein M2

C. causes disease with high seasonality in temperate climates

D. requires a high pH environment to activate membrane fusion

E. pandemics are associated with haemagglutinin drift

Answer 428

Influenza virus

A. replicates in the cytoplasm (FALSE)

B. encodes an ion channel protein M2 (TRUE)

C. causes disease with high seasonality in temperate climates (TRUE)

D. requires a high pH environment to activate membrane fusion (FALSE)

E. pandemics are associated with haemagglutinin drift (FALSE)

Question 429

Pattern-recognition receptors (PRRs)

A. are important for virus entry

B. mediate phagocytosis of free virus particles

C. activate the JAK-STAT signalling pathway within the infected cell

D. detect viral DNA in the cytoplasm

E. activate the IRF3 transcription factor within the infected cell

Answer 429

Pattern-recognition receptors (PRRs)

A. are important for virus entry (FALSE)

B. mediate phagocytosis of free virus particles (TRUE)

C. activate the JAK-STAT signalling pathway within the infected cell (FALSE)

D. detect viral DNA in the cytoplasm (TRUE)

E. activate the IRF3 transcription factor within the infected cell (TRUE)

Question 430

Human immunodeficiency virus (HIV)

A. binds to cells via chemokines

B. expresses several genes in addition to gag, pol and env B

C. converts its positive sense RNA genome into DNA via reverse transcription

D. is controlled by CD8* cytotoxic T lymphocytes in patients termed ‘slow progressors’

E. requires ribosomal frame-shifting to express env

Answer 430

Human immunodeficiency virus (HIV)

A. binds to cells via chemokines (FALSE)

B. expresses several genes in addition to gag, pol and env B (TRUE)

C. converts its positive sense RNA genome into DNA via reverse transcription (TRUE)

D. is controlled by CD8⁺ cytotoxic T lymphocytes in patients termed ‘slow progressors’ (TRUE)

E. requires ribosomal frame-shifting to express env (FALSE)

Question 431

Live attenuated vaccines have been used to control

A. foot and mouth disease virus

B. rinderpest virus

C. hepatitis A virus

D. poliovirus

E. Marek’s disease virus

Answer 431

Live attenuated vaccines have been used to control

A. foot and mouth disease virus (FALSE)

B. rinderpest virus (TRUE)

C. hepatitis A virus (TRUE)

D. poliovirus (TRUE)

E. Marek’s disease virus (TRUE)

Question 432

These features of smallpox helped make eradication possible

A. it is an enveloped virus

B. there is no animal reservoir

C. the virus causes persistent infections

D. it causes readily identifiable characteristic rash

E. there is no significant antigenic variation

Answer 432

These features of smallpox helped make eradication possible

A. it is an enveloped virus (FALSE)

B. there is no animal reservoir (TRUE)

C. the virus causes persistent infections (FALSE)

D. it causes readily identifiable characteristic rash (TRUE)

E. there is no significant antigenic variation (TRUE)

Question 433

In viral infections

A. herpesviruses establish persistent (latent) infections

B. hepatitis B establishes persistent (chronic) infection in about 90% of normal adults

C. measles virus only causes an acute infection

D. varicella zoster virus establishes latency in sensory ganglia

E. influenza viruses always cause acute infection

Answer 433

In viral infections

A. herpesviruses establish persistent (latent) infections (TRUE)

B. hepatitis B establishes persistent (chronic) infection in about 90% of normal adults (FALSE)

C. measles virus only causes an acute infection (FALSE)

D. varicella zoster virus establishes latency in sensory ganglia (TRUE)

E. influenza viruses always cause acute infection (TRUE)

Question 434

Fungi

A. Are Prokaryotic organisms that have a DNA genome with introns

B. Incorporate ergosterol into their cell wall

C. Have a cell wall predominantly composed of polysaccharides

D. Can contaminate food with toxins

E. Are useful in the production of antibiotics

Answer 434

Fungi

A. Are Prokaryotic organisms that have a DNA genome with introns (FALSE)

B. Incorporate ergosterol into their cell wall (TRUE)

C. Have a cell wall predominantly composed of polysaccharides (TRUE)

D. Can contaminate food with toxins (TRUE)

E. Are useful in the production of antibiotics (TRUE)

Question 435

The following statements are TRUE

A. Cryptococcus neoformans causes a slowly progressive disease

B. Invasive infections with Aspergillis fumigates has high fatality

C. Candida albicans is a common commensal organism of human mucous membranes

D. Structural barriers play a minor role in innate protection from fungal infection

E. Fungal cell wall synthesis can be blocked by caspofungin

Answer 435

The following statements are TRUE

A. Cryptococcus neoformans causes a slowly progressive disease (TRUE)

B. Invasive infections with Aspergillis fumigates has high fatality (TRUE)

C. Candida albicans is a common commensal organism of human mucous membranes (TRUE)

D. Structural barriers play a minor role in innate protection from fungal infection (FALSE)

E. Fungal cell wall synthesis can be blocked by caspofungin (TRUE)

Question 436

In haematopoiesis

A. The common myeloid precursor gives rise to neutrophils and mast cells

B. Platelets are derived from erythroblasts

C. Macrophages and dendritic cells can both be derived from monocytes

D. Plasma cells give rise to B cells

E. The common lymphoid progenitor gives rise to natural killer cells

Answer 436

In haematopoiesis

A. The common myeloid precursor gives rise to neutrophils and mast cells (TRUE)

B. Platelets are derived from erythroblasts (FALSE)

C. Macrophages and dendritic cells can both be derived from monocytes (TRUE)

D. Plasma cells give rise to B cells (FALSE)

E. The common lymphoid progenitor gives rise to natural killer cells (TRUE)

Question 437

The cell surface molecule

A. LFA-1 is a marker for T cells

B. CD8 binds to MHC class II molecules

C. VLA-4 is expressed on monocytes

D. CD4 is expressed on helper T cells

E. CD3 is involved in signal transduction in T cells

Answer 437

The cell surface molecule

A. LFA-1 is a marker for T cells (FALSE)

B. CD8 binds to MHC class II molecules (FALSE)

C. VLA-4 is expressed on monocytes (TRUE)

D. CD4 is expressed on helper T cells (TRUE)

E. CD3 is involved in signal transduction in T cells (TRUE)

Question 438

Pattern recognition receptors include:

A. TLR 5 which binds bacterial flagellin

B. TLR 3 which in conjunction with CD14 recognises bacterial LPS

C. NOD2 which recognises muramy| dipeptide

D. TLR9 which binds lipoteichoic acid

E. NLRP3 (also known as NALP3) which recognises cholesterol crystals

Answer 438

Pattern recognition receptors include:

A. TLR 5 which binds bacterial flagellin (TRUE)

B. TLR 3 which in conjunction with CD14 recognises bacterial LPS (FALSE)

C. NOD2 which recognises muramy| dipeptide (TRUE)

D. TLR9 which binds lipoteichoic acid (FALSE)

E. NLRP3 (also known as NALP3) which recognises cholesterol crystals (TRUE)

Question 439

In the acute inflammatory response

A. Histamine comes from stored sources and causes immediate vasodilation

B. Leukotrienes are actively synthesised by macrophages

C. C3a, C3b and C5a are derived from circulating complement components in plasma

D. NK cells are the first to arrive

E. CXCL8 is involved in neutrophil chemotaxis

Answer 439

In the acute inflammatory response

A. Histamine comes from stored sources and causes immediate vasodilation (TRUE)

B. Leukotrienes are actively synthesised by macrophages (TRUE)

C. C3a, C3b and C5a are derived from circulating complement components in plasma (TRUE)

D. NK cells are the first to arrive (FALSE)

E. CXCL8 is involved in neutrophil chemotaxis (TRUE)

Question 440

In the complement system

A. The classical pathway is usually first to act

B. The alternative pathway is the main complement pathway responsible for generating C3b for binding to a pathogen

C. Factor H increases activation of the alternative pathway

D. DAF disrupts the C3 convertase C3bBb

E. MCP makes C3b susceptible to cleavage by factor I

Answer 440

In the complement system

A. The classical pathway is usually first to act (FALSE)

B. The alternative pathway is the main complement pathway responsible for generating C3b for binding to a pathogen (TRUE)

C. Factor H increases activation of the alternative pathway (FALSE)

D. DAF disrupts the C3 convertase C3bBb (TRUE)

E. MCP makes C3b susceptible to cleavage by factor I (TRUE)

Question 441

Immunological tolerance

A. Can involve regulatory T cells that are positive for T-bet

B. In pregnancy involves IDO which catabolises tryptophan

C. Depends on the transcription factor IPEX in the thymus

D. Requires that all B cells with receptors that recognise self undergo apoptosis or anergy

E. Is affected by B7 on the T cell interacting with CD28 on the APC

Answer 441

Immunological tolerance

A. Can involve regulatory T cells that are positive for T-bet (FALSE)

B. In pregnancy involves IDO which catabolises tryptophan (TRUE)

C. Depends on the transcription factor IPEX in the thymus (FALSE)

D. Requires that all B cells with receptors that recognise self undergo apoptosis or anergy (FALSE)

E. Is affected by B7 on the T cell interacting with CD28 on the APC (FALSE)

Question 442

In transplantation

A. Direct recognition is where recipient T cells directly recognise HLA molecules not shared with the donor

B. Indirect recognition occurs only when MHC molecules are mismatched

C. HLA matching is more important for haemopoietic stem cell transplants than for liver transplants

D. HLA typing is not necessary with autologous transplants

E. A GVH (graft versus host) response is never advantageous

Answer 442

In transplantation

A. Direct recognition is where recipient T cells directly recognise HLA molecules not shared with the donor (TRUE)

B. Indirect recognition occurs only when MHC molecules are mismatched (FALSE)

C. HLA matching is more important for haemopoietic stem cell transplants than for liver transplants (TRUE)

D. HLA typing is not necessary with autologous transplants (TRUE)

E. A GVH (graft versus host) response is never advantageous (FALSE)

Question 443

Pathogen associated molecular patterns (PAMPs)

A. are highly conserved in evolution across species

B. are present in vertebrate hosts

C. are specific to the individual organism

D. can recognise double stranded RNA

E. include the lipid A component of lipopolysaccharide

Answer 443

Pathogen associated molecular patterns (PAMPs)

A. are highly conserved in evolution across species (TRUE)

B. are present in vertebrate hosts (FALSE)

C. are specific to the individual organism (FALSE)

D. can recognise double stranded RNA (FALSE)

E. include the lipid A component of lipopolysaccharide (TRUE)

Question 444

Regarding the innate and adaptive immune response to virus infections

A. Antibodies are often involved in killing cells infected by enveloped viruses

B. Cytoplasmic viral DNA can be sensed by pattern recognition receptors

C. NK cells generally play a role late in infection once an antigen-specific CD8* T-cell response has developed

D. Adenoviruses evade immune attack by preventing the transport of MHC-I molecules to the cell surface

E. EBV encodes a viral cytokine IL-10 that drives the immune system towards a TH1 response

Answer 444

Regarding the innate and adaptive immune response to virus infections

A. Antibodies are often involved in killing cells infected by enveloped viruses (TRUE)

B. Cytoplasmic viral DNA can be sensed by pattern recognition receptors (TRUE)

C. NK cells generally play a role late in infection once an antigen-specific CD8⁺ T-cell response has developed (FALSE)

D. Adenoviruses evade immune attack by preventing the transport of MHC-I molecules to the cell surface (TRUE)

E. EBV encodes a viral cytokine IL-10 that drives the immune system towards a TH1 response (FALSE)

Question 445

The following features of cytokines are ly described

A. Tregs express TGF-f which inhibits TH1 and TH2 cell differentiation

B. IL-6 is a fate-specifying cytokine for Try cell commitment

C. IL-6 is the major cytokine involved in stimulating acute phase protein release from the liver

D. IL-4 or IFN-γ can inhibit T_H17 cell differentiation

E. The fate specifying cytokine for T17 cells is IL-17

Answer 445

The following features of cytokines are ly described

A. Tregs express TGF-f which inhibits TH1 and TH2 cell differentiation (TRUE)

B. IL-6 is a fate-specifying cytokine for Try cell commitment (TRUE)

C. IL-6 is the major cytokine involved in stimulating acute phase protein release from the liver (TRUE)

D. IL-4 or IFN-γ can inhibit T_H17 cell differentiation (TRUE)

E. The fate specifying cytokine for T17 cells is IL-17 (FALSE)

Question 446

During T cell development and activation

A. The most potent professional antigen presenting cell is the macrophage

B. The signature transcription factors for Ty1 and Ty2 cells are T-bet and GATA3 respectively

C. Autoreactive naive T cells become anergic if they recognise MHC/peptide complexes in the absence of co-stimulation

D. Split tolerance is where T cells are tolerant but B cells are not

E. Tregs suppress the activation of naive T cell by producing IL-10 and TGFβ

Answer 446

During T cell development and activation

A. The most potent professional antigen presenting cell is the macrophage (FALSE)

B. The signature transcription factors for T_H1 and T_H2 cells are T-bet and GATA3 respectively (TRUE)

C. Autoreactive naive T cells become anergic if they recognise MHC/peptide complexes in the absence of co-stimulation (TRUE)

D. Split tolerance is where T cells are tolerant but B cells are not (TRUE)

E. Tregs suppress the activation of naive T cell by producing IL-10 and TGFβ (TRUE)

Question 447

In type IV hypersensitivity reactions

A. T_Η1 cells orchestrate the response by secreting cytokines, chemokines and cytotoxins

B. TNFα and TNFβ cause local tissue destruction

C. T_H1 cells are activated by recognising peptides that have been modified by haptens

D. T_H1 cells produce cytokines that recruit macrophages to the site of inflammation and activate them.

E. Usually occur within 2 to 4 hours of initiation

Answer 447

In type IV hypersensitivity reactions

A. T_Η1 cells orchestrate the response by secreting cytokines, chemokines and cytotoxins (TRUE)

B. TNFα and TNFβ cause local tissue destruction (TRUE)

C. T_H1 cells are activated by recognising peptides that have been modified by haptens (TRUE)

D. T_H1 cells produce cytokines that recruit macrophages to the site of inflammation and activate them. (TRUE)

E. Usually occur within 2 to 4 hours of initiation (FALSE)

Question 448

When cells suffer a loss of oxygen supply and lose control of energy production

A. Anaerobic glycolysis occurs causing an increase in pH

B. Cytosolic K⁺ levels increase and cytosolic Na⁺ levels decrease

C. Cellular swelling occurs due to increased water uptake

D. Cytosolic Ca²⁺ levels increase leading to increased activity of intracellular proteases, phospholipases and endonucleases

E. Protein synthesis is reduced due to ribosome detachment from the rough endoplasmic reticulum

Answer 448

When cells suffer a loss of oxygen supply and lose control of energy production

A. Anaerobic glycolysis occurs causing an increase in pH (FALSE)

B. Cytosolic K⁺ levels increase and cytosolic Na⁺ levels decrease (FALSE)

C. Cellular swelling occurs due to increased water uptake (TRUE)

D. Cytosolic Ca²⁺ levels increase leading to increased activity of intracellular proteases, phospholipases and endonucleases (TRUE)

E. Protein synthesis is reduced due to ribosome detachment from the rough endoplasmic reticulum (TRUE)

Question 449

The following anti-viral agents are correctly described

A. Tamiflu is an analogue of sialic acid and inhibits neuraminidase

B. Azidothymidine (AZT) is phosphorylated by cellular kinases and incorporated into the viral DNA causing chain termination

C. AZT is a better substrate for HIV reverse transcriptase than host DNA polymerase

D. Acyclovir is phosphorylated by the host thymidine kinase and incorporated into viral DNA by Herpes simplex virus DNA polymerase causing chain termination

E. Drugs that target non-structural proteins of Hepatitis C virus such as the NS2 and NS3 proteases and NS5A and NS5B RNA polymerase can cure patients of infection

Answer 449

The following anti-viral agents are correctly described

A. Tamiflu is an analogue of sialic acid and inhibits neuraminidase (TRUE)

B. Azidothymidine (AZT) is phosphorylated by cellular kinases and incorporated into the viral DNA causing chain termination (TRUE)

C. AZT is a better substrate for HIV reverse transcriptase than host DNA polymerase (TRUE)

D. Acyclovir is phosphorylated by the host thymidine kinase and incorporated into viral DNA by Herpes simplex virus DNA polymerase causing chain termination (FALSE)

E. Drugs that target non-structural proteins of Hepatitis C virus such as the NS2 and NS3 proteases and NS5A and NS5B RNA polymerase can cure patients of infection (TRUE)

Question 450

Which of the following correctly describe factors that influence the outcome of infection?

A. Varicella-zoster virus, the cause of chicken pox is mild infection in children but more serious in adults

B. Hepatitis B virus infection (HBV) of a neonate commonly establishes a chronic infection but infection later in life is more likely to be acute.

C. Epstein-Barr virus infection in childhood is asymptomatic

D. A male child who is infected with Hepatitis B virus as a neonate by a HBV infected mother has a 50% chance of dying of liver cancer due to chronic infection if untreated

E. SARS-CoV-2 infection of males is more serious than females. It is asymptomatic in children and shows increases in severity in the elderly

Answer 450

Which of the following correctly describe factors that influence the outcome of infection?

A. Varicella-zoster virus, the cause of chicken pox is mild infection in children but more serious in adults (TRUE)

B. Hepatitis B virus infection (HBV) of a neonate commonly establishes a chronic infection but infection later in life is more likely to be acute. (TRUE)

C. Epstein-Barr virus infection in childhood is asymptomatic (TRUE)

D. A male child who is infected with Hepatitis B virus as a neonate by a HBV infected mother has a 50% chance of dying of liver cancer due to chronic infection if untreated (TRUE)

E. SARS-CoV-2 infection of males is more serious than females. It is asymptomatic in children and shows increases in severity in the elderly (TRUE)

Question 451

Regarding the control of viral infections

A. Amantadine and rimantadine inhibit influenza virus entry by blocking the M2 proton pump

B. Saquinavir and ritonavir inhibit HIV specific proteases preventing completion of virus assembly

C. The Yellow fever virus vaccine (1937) was the first live attenuated virus vaccine developed. Live attenuated measles, mumps and rubella vaccines were developed later and all are still used today.

D. Vaccination helped in the eradication of smallpox and rinderpest

E. Hepatitis B virus is controlled by a subunit vaccine made from the Hepatitis B surface antigen (HBsAg) expressed in bacteria

Answer 451

Regarding the control of viral infections

A. Amantadine and rimantadine inhibit influenza virus entry by blocking the M2 proton pump (TRUE)

B. Saquinavir and ritonavir inhibit HIV specific proteases preventing completion of virus assembly (TRUE)

C. The Yellow fever virus vaccine (1937) was the first live attenuated virus vaccine developed. Live attenuated measles, mumps and rubella vaccines were developed later and all are still used today. (TRUE)

D. Vaccination helped in the eradication of smallpox and rinderpest (TRUE)

E. Hepatitis B virus is controlled by a subunit vaccine made from the Hepatitis B surface antigen (HBsAg) expressed in bacteria (FALSE)

Question 452

Regarding coronavirus epidemics in humans that cause high mortality

A. COVID-19 is a +ve ssRNA virus

B. Coronaviruses have large genomes and encode proof-reading machinery to repair replication errors

C. The spike (S) protein is responsible for binding to host cells and for membrane fusion

D. The case fatality rate for COVID-19 is ~ 0.3%

E. Remdesivir is an inhibitor of the virus DNA-dependent DNA polymerase and inhibits chain elongation

Answer 452

Regarding coronavirus epidemics in humans that cause high mortality

A. COVID-19 is a +ve ssRNA virus (FALSE)

B. Coronaviruses have large genomes and encode proof-reading machinery to repair replication errors (TRUE)

C. The spike (S) protein is responsible for binding to host cells and for membrane fusion (TRUE)

D. The case fatality rate for COVID-19 is ~ 0.3% (TRUE)

E. Remdesivir is an inhibitor of the virus DNA-dependent DNA polymerase and inhibits chain elongation (FALSE)

Question 453

Mycobacterium tuberculosis is the cause of significant morbidity and mortality. Which of the following statements are and which are false?

A. Granulomata formed in response to Mycobacterium tuberculosis often contain significant numbers of neutrophils

B. Chronic tuberculosis most often occurs in the lungs

C. In initial or primary infection with Mycobacterium tuberculosis, interaction between CD4+ T_H1 T cells and macrophages leads to formation of granulomata in the draining lymph nodes

D. Mycobacteria have a cell wall that doesn't take up stains normally used in histology and microbiology. They are often referred to as acid and alcohol-fast bacilli

E. Giant cells associated with Mycobacterial infection are also called Langerhans cells

Answer 453

Mycobacterium tuberculosis is the cause of significant morbidity and mortality. Which of the following statements are and which are false?

A. Granulomata formed in response to Mycobacterium tuberculosis often contain significant numbers of neutrophils (FALSE)

B. Chronic tuberculosis most often occurs in the lungs (TRUE)

C. In initial or primary infection with Mycobacterium tuberculosis, interaction between CD4⁺ T_H1 T cells and macrophages leads to formation of granulomata in the draining lymph nodes (TRUE)

D. Mycobacteria have a cell wall that doesn't take up stains normally used in histology and microbiology. They are often referred to as acid and alcohol-fast bacilli (TRUE)

E. Giant cells associated with Mycobacterial infection are also called Langerhans cells (FALSE)

Question 454

TNFα is a key cytokine in inflammatory responses

A. It stimulates dendritic cell maturation and migration to regional lymph nodes

B. It induces adhesion molecule expression on vascular endothelium and primes newly recruited neutrophils

C. Together with IL-6 and IL-1 it stimulates the fever response and is known as an endogenous pyrogen

D. It increases vascular permeability which leads to increased fluid drainage to regional lymph nodes

E. lt triggers platelet activation and clotting

Answer 454

TNFα is a key cytokine in inflammatory responses

A. It stimulates dendritic cell maturation and migration to regional lymph nodes (TRUE)

B. It induces adhesion molecule expression on vascular endothelium and primes newly recruited neutrophils (TRUE)

C. Together with IL-6 and IL-1 it stimulates the fever response and is known as an endogenous pyrogen (TRUE)

D. It increases vascular permeability which leads to increased fluid drainage to regional lymph nodes (TRUE)

E. lt triggers platelet activation and clotting (TRUE)

Question 455

The nature of the immune response to pathogens is strongly influenced by the site of infection

A. An appropriate response for pathogens that reside on epithelial surfaces is the production of IgA antibody and antimicrobial peptides

B. An appropriate response for pathogens like viruses that replicate in the cytoplasm of a cell is to kill the cell with an activated macrophage

C. An appropriate response for pathogens that reside in vesicular compartments in macrophages is to kill the host cell with a cytotoxic T cell

D. An appropriate response for pathogens like helminths that are too big to phagocytose is for eosinophils to deposit harmful substances on their surface

E. The generation of Ty1 and Ty17 cell responses is inhibited by IL-4

Answer 455

The nature of the immune response to pathogens is strongly influenced by the site of infection

A. An appropriate response for pathogens that reside on epithelial surfaces is the production of IgA antibody and antimicrobial peptides (TRUE)

B. An appropriate response for pathogens like viruses that replicate in the cytoplasm of a cell is to kill the cell with an activated macrophage (FALSE)

C. An appropriate response for pathogens that reside in vesicular compartments in macrophages is to kill the host cell with a cytotoxic T cell (FALSE)

D. An appropriate response for pathogens like helminths that are too big to phagocytose is for eosinophils to deposit harmful substances on their surface (TRUE)

E. The generation of T_H1 and T_H17 cell responses is inhibited by IL-4 (TRUE)

Question 456

The immune system can be harnessed to help clear cancer cells. Which of the following are  true and which are false?

A. CTLA4 normally inhibits activation of naive T cells by competing with CD28 for binding to CD80 or CD86

B. PD1 is expressed on activated T cells and can be blocked by anti-PD1 antibodies. This prevents negative signalling inactivating the T cell

C. Blocking inhibitory receptors on T cells is an effective therapy for cancers that have relatively few mutations

D. To be effective in anti-cancer therapy anti-PD1 antibodies should crosslink and activate PD1 that is present on the T cell surface

E. Ipilimumab (anti-PD1) is approved for use in immune checkpoint inhibition in the treatment of metastatic melanoma

Answer 456

The immune system can be harnessed to help clear cancer cells. Which of the following are  true and which are false?

A. CTLA4 normally inhibits activation of naive T cells by competing with CD28 for binding to CD80 or CD86 (TRUE)

B. PD1 is expressed on activated T cells and can be blocked by anti-PD1 antibodies. This prevents negative signalling inactivating the T cell (TRUE)

C. Blocking inhibitory receptors on T cells is an effective therapy for cancers that have relatively few mutations (FALSE)

D. To be effective in anti-cancer therapy anti-PD1 antibodies should crosslink and activate PD1 that is present on the T cell surface (FALSE)

E. Ipilimumab (anti-PD1) is approved for use in immune checkpoint inhibition in the treatment of metastatic melanoma (FALSE)

Question 457

Regarding cells of the immune system

A. Neutrophils, eosinophils and basophils are phagocytic granulocytes 

B. Mast cells can be activated by C3a and by C5a 

C. NK cells are regulated by balancing signals from activatory and inhibitory receptors 

D. Neutrophil extracellular traps are composed mainly of collagen 

E. B cells, T cells and NK cells are part of the lymphoid lineage 

Answer 457

Regarding cells of the immune system

A. Neutrophils, eosinophils and basophils are phagocytic granulocytes (FALSE)

B. Mast cells can be activated by C3a and by C5a (TRUE)

C. NK cells are regulated by balancing signals from activatory and inhibitory receptors (TRUE)

D. Neutrophil extracellular traps are composed mainly of collagen (FALSE)

E. B cells, T cells and NK cells are part of the lymphoid lineage (TRUE)

Question 458

The cytokine(s)

A. TNFα induces adhesion molecule expression on endothelial cells facilitating neutrophil recruitment 

B. CXCL8 and IL-12 help the recruitment and activation of NK cells 

C. IL-4 induces Th1 responses 

D. IL-1 is the major cytokine responsible for inducing the acute phase response 

E. IL-10 is anti-inflammatory 

Answer 458

The cytokine(s)

A. TNFα induces adhesion molecule expression on endothelial cells facilitating neutrophil recruitment (TRUE)

B. CXCL8 and IL-12 help the recruitment and activation of NK cells (TRUE)

C. IL-4 induces Th1 responses (FALSE)

D. IL-1 is the major cytokine responsible for inducing the acute phase response (FALSE)

E. IL-10 is anti-inflammatory (TRUE)

Question 459

Regarding acute inflammation

A. the acute inflammatory exudate is a filtrate that is devoid of large proteins 

B. tight adhesion of neutrophils to endothelial cells is mediated by the integrin LFA-1 binding to ICAMs 

C. leukocyte adhesion deficiency (LAD) causes recurrent life- threatening infections and is due to defects in LFA-1 

D. CXCL8 induces tight binding of LFA-1 to ICAM-1 and also forms a chemokine gradient towards the site of infection 

E. lipoxin is an anti-inflammatory lipid mediator that acts as a ‘stop signal’ for acute inflammation 

Answer 459

Regarding acute inflammation

A. the acute inflammatory exudate is a filtrate that is devoid of large proteins (FALSE)

B. tight adhesion of neutrophils to endothelial cells is mediated by the integrin LFA-1 binding to ICAMs (TRUE)

C. leukocyte adhesion deficiency (LAD) causes recurrent life- threatening infections and is due to defects in LFA-1 (TRUE)

D. CXCL8 induces tight binding of LFA-1 to ICAM-1 and also forms a chemokine gradient towards the site of infection (TRUE)

E. lipoxin is an anti-inflammatory lipid mediator that acts as a ‘stop signal’ for acute inflammation (TRUE)

Question 460

The complement component

A. C3bBb is the alternative pathway C3 convertase 

B. factor H has decay-accelerating capacity but no factor I cofactor activity 

C. C3a is an anaphylatoxin that stimulates inflammation 

D. C5 is structurally related to C3 and has a highly reactive internal thioester bond 

E. protectin is the only known positive regulator of the alternative pathway C3 convertase C3bBb 

Answer 460

The complement component

A. C3bBb is the alternative pathway C3 convertase (TRUE)

B. factor H has decay-accelerating capacity but no factor I cofactor activity (FALSE)

C. C3a is an anaphylatoxin that stimulates inflammation (TRUE)

D. C5 is structurally related to C3 and has a highly reactive internal thioester bond (FALSE)

E. protectin is the only known positive regulator of the alternative pathway C3 convertase C3bBb (FALSE)

Question 461

NK cells

A. kill target cells using perforin and granzymes 

B. kill target cells by antibody dependent cell cytotoxicity (ADCC) 

C. kill virus infected cells through recognition of MHC class I molecules presenting virus-derived peptides 

D. have inhibitory receptors that recognise classical MHC class I molecules 

E. activate macrophages by secreting IFN-γ 

Answer 461

NK cells

A. kill target cells using perforin and granzymes (TRUE)

B. kill target cells by antibody dependent cell cytotoxicity (ADCC) (TRUE)

C. kill virus infected cells through recognition of MHC class I molecules presenting virus-derived peptides (FALSE)

D. have inhibitory receptors that recognise classical MHC class I molecules (TRUE)

E. activate macrophages by secreting IFN-γ (TRUE)

Question 462

In the complement system

A. generation of C3(H2O) is a reversible reaction 

B. C4b can covalently attach to pathogen surfaces 

C. mannose-binding lectin is a soluble pattern recognition receptor 

D. deficiency in factor I results in uncontrolled alternative pathway activation and C3 depletion 

E. individuals deficient in complement component C1 are predisposed to immune-complex disease 

Answer 462

In the complement system

A. generation of C3(H2O) is a reversible reaction (FALSE)

B. C4b can covalently attach to pathogen surfaces (TRUE)

C. mannose-binding lectin is a soluble pattern recognition receptor (TRUE)

D. deficiency in factor I results in uncontrolled alternative pathway activation and C3 depletion (TRUE)

E. individuals deficient in complement component C1 are predisposed to immune-complex disease (TRUE)

Question 463

Pattern Recognition Receptors

A. include TLR4 which recognises components of Gram–negative bacterial LPS 

B. include NOD2 which recognises muramyl dipeptide and is often mutated in individuals with Crohn’s disease 

C. recognise either pathogen associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs), but not both 

D. are all transmembrane signalling receptors 

E. that recognise bacterial cell wall components often activate pro- inflammatory responses through NF-kB 

Answer 463

Pattern Recognition Receptors

A. include TLR4 which recognises components of Gram–negative bacterial LPS (TRUE)

B. include NOD2 which recognises muramyl dipeptide and is often mutated in individuals with Crohn’s disease (TRUE)

C. recognise either pathogen associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs), but not both (FALSE)

D. are all transmembrane signalling receptors (FALSE)

E. that recognise bacterial cell wall components often activate pro- inflammatory responses through NF-kB (TRUE)

Question 464

Macrophages

A. act as tissue-resident sentinel cells 

B. produce the endogenous pyrogen CXCL8 

C. rapidly release granules containing preformed mediators of inflammation such as histamine 

D. produce TNFα which increases vascular permeability 

E. produce IL-12 which activates NK cells and promotes Th1 cell differentiation 

Answer 464

Macrophages

A. act as tissue-resident sentinel cells (TRUE)

B. produce the endogenous pyrogen CXCL8 (TRUE)

C. rapidly release granules containing preformed mediators of inflammation such as histamine (FALSE)

D. produce TNFα which increases vascular permeability (TRUE)

E. produce IL-12 which activates NK cells and promotes Th1 cell differentiation (TRUE)

Question 465

MHC class I molecules

A. HLA-A, HLA-B and HLA-C are structurally related alleles of each other 

B. bind peptides that are about 9 amino acids in length 

C. associate with peptides in the endoplasmic reticulum 

D. covalently associate with beta-2 microglobulin 

E. bind the accessory molecule CD4 

Answer 465

MHC class I molecules

A. HLA-A, HLA-B and HLA-C are structurally related alleles of each other (TRUE)

B. bind peptides that are about 9 amino acids in length (TRUE)

C. associate with peptides in the endoplasmic reticulum (TRUE)

D. covalently associate with beta-2 microglobulin (FALSE)

E. bind the accessory molecule CD4 (FALSE)

Question 466

In the immune system

A. all antibody production requires T cell help 

B. follicular dendritic cells are professional antigen presenting cells that process and present antigen to T cells

C. MHC class II molecules associate with peptide in endosomal compartments

D. B cells and T cells mainly enter lymph nodes via the afferent lymphatics 

E. secondary lymphoid organs include the thymus, lymph nodes and spleen 

Answer 466

In the immune system

A. all antibody production requires T cell help (FALSE)

B. follicular dendritic cells are professional antigen presenting cells that process and present antigen to T cells (FALSE)

C. MHC class II molecules associate with peptide in endosomal compartments (TRUE)

D. B cells and T cells mainly enter lymph nodes via the afferent lymphatics (FALSE)

E. secondary lymphoid organs include the thymus, lymph nodes and spleen (FALSE)

Question 467

In the generation of B cell receptor diversity

A. complementarity determining regions 1 and 2 (CDRs 1 and 2) are encoded entirely within variable gene segments 

B. random nucleotides can be added to the junctions between heavy chain variable and diversity gene segments

C. junctional diversity in the B cell receptor is much greater than in the T cell receptor 

D. somatic hypermutation occurs in the bone marrow 

E. receptor editing involves pairing of the rearranged heavy chain with a different light chain

Answer 467

In the generation of B cell receptor diversity

A. complementarity determining regions 1 and 2 (CDRs 1 and 2) are encoded entirely within variable gene segments (TRUE)

B. random nucleotides can be added to the junctions between heavy chain variable and diversity gene segments (TRUE)

C. junctional diversity in the B cell receptor is much greater than in the T cell receptor (FALSE)

D. somatic hypermutation occurs in the bone marrow (FALSE)

E. receptor editing involves pairing of the rearranged heavy chain with a different light chain (TRUE)

Question 468

Regarding the MHC

A. peptides that are loaded onto class II molecules are largely generated by the proteasome 

B. CLIP is a small invariant chain-derived peptide that binds to MHC class II molecules 

C. peptides from exogenous proteins are presented to T cells, predominantly by MHC class II molecules 

D. MHC class I molecules rarely present self-peptide 

E. most cells of the body express MHC class II molecules 

Answer 468

Regarding the MHC

A. peptides that are loaded onto class II molecules are largely generated by the proteasome (FALSE)

B. CLIP is a small invariant chain-derived peptide that binds to MHC class II molecules (TRUE)

C. peptides from exogenous proteins are presented to T cells, predominantly by MHC class II molecules (TRUE)

D. MHC class I molecules rarely present self-peptide (FALSE)

E. most cells of the body express MHC class II molecules (FALSE)

Question 469

Regarding T cells

A. CD4 and CD8 double positive T cells are mainly found in lymph nodes and the spleen 

B. the vast majority of developing T cells fail positive selection 

C. most naïve T cells are activated by dendritic cells at the site of infection 

D. cortical thymic epithelial cells express both MHC class I and MHC class II molecules 

E. CD40 and B7 are co-stimulatory molecules present on dendritic cells 

Answer 469

Regarding T cells

A. CD4 and CD8 double positive T cells are mainly found in lymph nodes and the spleen (FALSE)

B. the vast majority of developing T cells fail positive selection (TRUE)

C. most naïve T cells are activated by dendritic cells at the site of infection (FALSE)

D. cortical thymic epithelial cells express both MHC class I and MHC class II molecules (TRUE)

E. CD40 and B7 are co-stimulatory molecules present on dendritic cells (TRUE)

Question 470

Of the T cell subsets

A. T_H17 cells promote neutrophil recruitment and are involved in defence against extracellular bacteria and fungi 

B. T_H2 cells express GATA3

C. T_H1 cells promote responses against intracellular bacteria and protozoa

D. T_H2 cells express MHC class I 

E. natural regulatory T cells (Tregs) are thought to be educated in the periphery when they meet antigen 

Answer 470

Of the T cell subsets

A. T_H17 cells promote neutrophil recruitment and are involved in defence against extracellular bacteria and fungi (TRUE)

B. T_H2 cells express GATA3 (TRUE)

C. T_H1 cells promote responses against intracellular bacteria and protozoa (TRUE)

D. T_H2 cells express MHC class I (TRUE)

E. natural regulatory T cells (Tregs) are thought to be educated in the periphery when they meet antigen (FALSE)

Question 471

Regarding autoimmunity

A. Graves’ disease results from auto-antibody stimulation of the TSH receptor 

B. anti-nuclear and anti-cytoplasmic auto-antibodies are present in patients with systemic lupus erythematosus 

C. myasthenia gravis results from auto-antibody binding to the acetylcholine receptor 

D. the majority of autoimmune conditions occur with equal frequency in men and women 

E. In assessing the probability of developing a disease a relative risk of >40 indicates that >40% of individuals with the susceptibility gene are expected to develop the disease 

Answer 471

Regarding autoimmunity

A. Graves’ disease results from auto-antibody stimulation of the TSH receptor (TRUE)

B. anti-nuclear and anti-cytoplasmic auto-antibodies are present in patients with systemic lupus erythematosus (TRUE)

C. myasthenia gravis results from auto-antibody binding to the acetylcholine receptor (TRUE)

D. the majority of autoimmune conditions occur with equal frequency in men and women (FALSE)

E. In assessing the probability of developing a disease a relative  risk of >40 indicates that >40% of individuals with the susceptibility gene are expected to develop the disease (FALSE)

Question 472

Hypersensitivity reactions

A. involving IgE are classed as Type 1 

B. to foetal RhD red blood cell antigens can be prevented by administration of the anti-Rh antibody preparation RhoGam to the mother 

C. to penicillin may involve IgE and result in anaphylactic shock 

D. to unmatched ABO blood group antigens are only a concern in previously transfused recipients 

E. mediated by immune-complex formation include serum sickness and the Arthus reaction 

Answer 472

Hypersensitivity reactions

A. involving IgE are classed as Type 1 (TRUE)

B. to foetal RhD red blood cell antigens can be prevented by administration of the anti-Rh antibody preparation RhoGam to the mother (TRUE)

C. to penicillin may involve IgE and result in anaphylactic shock (TRUE)

D. to unmatched ABO blood group antigens are only a concern in previously transfused recipients (FALSE)

E. mediated by immune-complex formation include serum sickness and the Arthus reaction (TRUE)

Question 473

In transplantation

A. hyperacute rejection can be complement-mediated 

B. HLA matching is very important in liver transplants 

C. syngeneic transplants are transplants between two genetically identical individuals  

D. minor transplantation antigens may be derived from MHC molecules 

E. chronic rejection may be due to gradual damage to the blood vessels of the graft 

Answer 473

In transplantation

A. hyperacute rejection can be complement-mediated (TRUE)

B. HLA matching is very important in liver transplants (FALSE)

C. syngeneic transplants are transplants between two genetically identical individuals (TRUE)

D. minor transplantation antigens may be derived from MHC molecules (FALSE)

E. chronic rejection may be due to gradual damage to the blood vessels of the graft (TRUE)

Question 474

The following are used by viruses to compensate for their limited coding capacity

A. small non-coding regions 

B. overlapping open reading frames 

C. segmented genomes 

D. splicing 

E. diploid genomes 

Answer 474

The following are used by viruses to compensate for their limited coding capacity

A. small non-coding regions (TRUE)

B. overlapping open reading frames (TRUE)

C. segmented genomes (FALSE)

D. splicing (TRUE)

E. diploid genomes (FALSE)

Question 475

Regarding virus binding and penetration

A. carbohydrates function as receptors for some viruses 

B. acidic conditions (pH <5.5) are required for fusion of virus envelopes with the plasma membrane 

C. receptor-binding defines the tissue tropism for influenza virus 

D. the eclipse phase describes the time delay between virus uncoating and production of new progeny virions 

E. neutralising antibodies block HIV infection by binding the virus capsid protein 

Answer 475

Regarding virus binding and penetration

A. carbohydrates function as receptors for some viruses (TRUE)

B. acidic conditions (pH <5.5) are required for fusion of virus envelopes with the plasma membrane (FALSE)

C. receptor-binding defines the tissue tropism for influenza virus (FALSE)

D. the eclipse phase describes the time delay between virus uncoating and production of new progeny virions (TRUE)

E. neutralising antibodies block HIV infection by binding the  virus capsid protein (FALSE)

Question 476

The following purified virus genomes are infectious if artificially introduced into cells

A. herpes simplex virus 

B. vaccinia virus 

C. poliovirus 

D. influenza virus 

E. HIV 

Answer 476

The following purified virus genomes are infectious if artificially introduced into cells

A. herpes simplex virus (TRUE)

B. vaccinia virus (FALSE)

C. poliovirus (TRUE)

D. influenza virus (FALSE)

E. HIV (FALSE)

Question 477

Regarding host cell modification by virus infection

A. poliovirus protease cleaves host RNA polymerase II 

B. the observation of Negri bodies indicates the cytopathic effect caused by rabies virus infection 

C. herpesviruses stimulate deoxyribonucleotide synthesis through the activity of virally-encoded ribonucleotide reductase

D. cells are stimulated into cycle by influenza virus infection 

E. transformation is a common event following retrovirus integration 

Answer 477

Regarding host cell modification by virus infection

A. poliovirus protease cleaves host RNA polymerase II (FALSE)

B. the observation of Negri bodies indicates the cytopathic effect caused by rabies virus infection (TRUE)

C. herpesviruses stimulate deoxyribonucleotide synthesis through the activity of virally-encoded ribonucleotide reductase (TRUE)

D. cells are stimulated into cycle by influenza virus infection (FALSE)

E. transformation is a common event following retrovirus integration (FALSE)

Question 478

Mechanisms viruses use to evade host immune responses include

A. antigenic drift 

B. inhibiting JAK-STAT signalling 

C. preventing peptide loading of MHC class I molecules 

D. entering a latent state 

E. inhibition of host mRNA translation 

Answer 478

Mechanisms viruses use to evade host immune responses include

A. antigenic drift (TRUE)

B. inhibiting JAK-STAT signalling (TRUE)

C. preventing peptide loading of MHC class I molecules (TRUE)

D. entering a latent state (TRUE)

E. inhibition of host mRNA translation (TRUE)

Question 479

Zika virus

A. is a member of family Filoviridae 

B. is closely related to dengue virus 

C. can be transmitted by mosquitos 

D. can be transmitted during sexual intercourse 

E. causes severe haemorrhagic fever in adults  

Answer 479

Zika virus

A. is a member of family Filoviridae (FALSE)

B. is closely related to dengue virus (TRUE)

C. can be transmitted by mosquitos (TRUE)

D. can be transmitted during sexual intercourse (TRUE)

E. causes severe haemorrhagic fever in adults (FALSE)

Question 480

Influenza A virus

A. infections can be treated with Tamiflu, a sialic acid analogue 

B. has natural reservoirs in wild birds 

C. genomes are composed of multiple DNA segments 

D. requires a high pH environment to activate membrane fusion 

E. pandemics are associated with antigenic shift 

Answer 480

Influenza A virus

A. infections can be treated with Tamiflu, a sialic acid analogue (TRUE)

B. has natural reservoirs in wild birds (TRUE)

C. genomes are composed of multiple DNA segments (FALSE)

D. requires a high pH environment to activate membrane fusion (FALSE)

E. pandemics are associated with antigenic shift (TRUE)

Question 481

Regarding hepatitis viruses

A. all hepatitis viruses are picornaviruses 

B. chronic infection with hepatitis C virus can be cured by drug treatment 

C. there is an effective subunit vaccine to prevent hepatitis A virus infection 

D. translation of mRNA encoding hepatitis A virus polyprotein is controlled by an internal ribosome entry site (IRES) 

E. all hepatitis viruses are primarily transmitted via contaminated blood 

Answer 481

Regarding hepatitis viruses

A. all hepatitis viruses are picornaviruses (FALSE)

B. chronic infection with hepatitis C virus can be cured by drug treatment (TRUE)

C. there is an effective subunit vaccine to prevent hepatitis A virus infection (FALSE)

D. translation of mRNA encoding hepatitis A virus polyprotein is controlled by an internal ribosome entry site (TRUE)

E. all hepatitis viruses are primarily transmitted via contaminated blood (FALSE)

Question 482

Regarding prevention and treatment of viral disease

A. quarantine and vaccination are effective strategies for eradication of viral diseases 

B. acyclovir inhibits virus DNA replication following its phosphorylation by the viral thymidine kinase 

C. live vaccines have the advantage of inducing long-lived humoral and cellular immunity 

D. supply of maternal antibodies via breast milk is an example of passive immunisation 

E. Highly Active Anti-Retroviral Therapy (HAART) targets multiple steps of the virus lifecycle simultaneously 

Answer 482

Regarding prevention and treatment of viral disease

A. quarantine and vaccination are effective strategies for eradication of viral diseases (TRUE)

B. acyclovir inhibits virus DNA replication following its phosphorylation by the viral thymidine kinase (TRUE)

C. live vaccines have the advantage of inducing long-lived humoral and cellular immunity (TRUE)

D. supply of maternal antibodies via breast milk is an example of passive immunisation (TRUE)

E. Highly Active Anti-Retroviral Therapy (HAART) targets multiple steps of the virus lifecycle simultaneously (TRUE)

Question 483

Regarding fungi

A. the fungal cell wall is mainly composed of polysaccharide 

B. a typical yeast has about 6000 genes 

C. the fungal PAMP β-1,3 glucan is recognised by Dectin-1 

D. Candida albicans can become problematic after treatment of the host with broad-spectrum antibiotics 

E. amphotericin is an antifungal drug that targets β-1,3 glucan synthesis 

Answer 483

Regarding fungi

A. the fungal cell wall is mainly composed of polysaccharide (TRUE)

B. a typical yeast has about 6000 genes (TRUE)

C. the fungal PAMP β-1,3 glucan is recognised by Dectin-1 (TRUE)

D. Candida albicans can become problematic after treatment of the host with broad-spectrum antibiotics (TRUE)

E. amphotericin is an antifungal drug that targets β-1,3 glucan synthesis (FALSE)

Question 484

Fungal infection

A. of dead keratinised tissue is known as “ringworm” 

B. by Pneumocystis jirovecii depends on bat-to-human transmission 

C. by Cryptococcus neoformans is often contracted by inhalation from bird droppings 

D. invasive infections caused by Aspergillus fumigatus have a high fatality 

E. by Candida albicans causes chronic disfiguring nail infections 

Answer 484

Fungal infection

A. of dead keratinised tissue is known as “ringworm” (TRUE)

B. by Pneumocystis jirovecii depends on bat-to-human transmission (FALSE)

C. by Cryptococcus neoformans is often contracted by inhalation from bird droppings (TRUE)

D. invasive infections caused by Aspergillus fumigatus have a high fatality (TRUE)

E. by Candida albicans causes chronic disfiguring nail infections (TRUE)

Question 485

Regarding bacterial toxins

A. pneumolysin, streptolysin O, Staphylococcal alpha-toxin and E. coli haemolysin all form pores in host cell membranes 

B. tetanus toxin is a protease that cleaves synaptobrevin, blocking release of inhibitory neurotransmitters in the CNS 

C. diphtheria toxin modifies host ribosomal RNA to inhibit translation 

D. membrane-damaging Clostridium perfringens alpha-toxin is a phospholipase detected on egg yolk agar (the Nagler test) 

E. cholera toxin is a homologue of host adenylate cyclase 

Answer 485

Regarding bacterial toxins

A. pneumolysin, streptolysin O, Staphylococcal alpha-toxin and E. coli haemolysin all form pores in host cell membranes (TRUE)

B. tetanus toxin is a protease that cleaves synaptobrevin, blocking release of inhibitory neurotransmitters in the CNS (TRUE)

C. diphtheria toxin modifies host ribosomal RNA to inhibit translation (FALSE)

D. membrane-damaging Clostridium perfringens alpha-toxin is a phospholipase detected on egg yolk agar (the Nagler test) (TRUE)

E. cholera toxin is a homologue of host adenylate cyclase (FALSE)

Question 486

In pathogenic bacteria

A. growth typically involves haploid chromosome replication and binary fission to generate two identical progeny cells 

B. question removed

C. endotoxin is the lipid A component of bacterial LPS 

D. transduction involves DNA transfer following contact between two bacterial cells 

E. peptidoglycan comprises alternating sugars cross-linked by peptides, and is cleaved by lysozyme 

Answer 486

In pathogenic bacteria

A. growth typically involves haploid chromosome replication and binary fission to generate two identical progeny cells (TRUE)

B. question removed

C. endotoxin is the lipid A component of bacterial LPS (TRUE)

D. transduction involves DNA transfer following contact between two bacterial cells (FALSE)

E. peptidoglycan comprises alternating sugars cross-linked by peptides, and is cleaved by lysozyme (TRUE)

Question 487

In tuberculosis

A. human disease can be zoonotic, via milk of M. bovis-infected cattle 

B. granulomatous disease is typically resolved by a Th2 response 

C. immunity is conferred by the killed BCG vaccine 

D. mycobacteria are visible by Ziehl-Neelsen staining 

E. immunity to M. tuberculosis is detected as a T cell response by the tuberculin skin test 

Answer 487

In tuberculosis

A. human disease can be zoonotic, via milk of M. bovis-infected cattle (TRUE)

B. granulomatous disease is typically resolved by a T_H2 response (FALSE)

C. immunity is conferred by the killed BCG vaccine (FALSE)

D. mycobacteria are visible by Ziehl-Neelsen staining (TRUE)

E. immunity to M. tuberculosis is detected as a T cell response by the tuberculin skin test (TRUE)

Question 488

In gastrointestinal infections

A. Helicobacter pylori is a motile Gram-negative bacterium for which VacA is a key virulence factor 

B. ETEC causes travellers’ diarrhoea by bacteria entering host intestinal cells and inducing inflammation 

C. Listeria invades intestinal cells by receptor-mediated endocytosis to establish an intracellular infection, but it can become systemic and cross the blood-brain barrier 

D. Clostridium difficile secretes toxins that disrupt the actin cytoskeleton and epithelial tight junctions 

E. Shiga toxin inhibits Rho/Ras GTPases, causing kidney damage 

Answer 488

In gastrointestinal infections

A. Helicobacter pylori is a motile Gram-negative bacterium for which VacA is a key virulence factor (TRUE)

B. ETEC causes travellers’ diarrhoea by bacteria entering host intestinal cells and inducing inflammation (FALSE)

C. Listeria invades intestinal cells by receptor-mediated endocytosis to establish an intracellular infection, but it can become systemic and cross the blood-brain barrier (TRUE)

D. Clostridium difficile secretes toxins that disrupt the actin cytoskeleton and epithelial tight junctions (TRUE)

E. Shiga toxin inhibits Rho/Ras GTPases, causing kidney damage (FALSE)

Question 489

Diseases caused by the following are often zoonotic

A. Salmonella typhi 

B. Bordetella pertussis 

C. Salmonella enterica

D. Yersinia pestis 

E. Vibrio cholera 

Answer 489

Diseases caused by the following are often zoonotic

A. Salmonella typhi (FALSE)

B. Bordetella pertussis (FALSE)

C. Salmonella enterica (TRUE)

D. Yersinia pestis (TRUE)

E. Vibrio cholera (FALSE)

Question 490

Uropathogenic E.coli

A. typically come from the host’s own intestinal flora, causing ascending inflammatory infection of the bladder and kidney 

B. colonise the kidney using specific adhesins on the tip of P pili that bind receptors on kidney epithelial cells

C. P pili are assembled from subunits that are secreted into the periplasm and then incorporated into the outer membrane by the chaperone-usher pathway 

D. kidney damage is largely caused directly by the pore-forming haemolysin toxin and indirectly by lipid A-triggered inflammation 

E. motility is afforded by bacterial surface flagella, which contain PAMPs recognised by TLR5

Answer 490

Uropathogenic E.coli

A. typically come from the host’s own intestinal flora, causing ascending inflammatory infection of the bladder and kidney (TRUE)

B. colonise the kidney using specific adhesins on the tip of P pili that bind receptors on kidney epithelial cells (TRUE)

C. P pili are assembled from subunits that are secreted into the periplasm and then incorporated into the outer membrane by the chaperone-usher pathway (TRUE)

D. kidney damage is largely caused directly by the pore-forming haemolysin toxin and indirectly by lipid A-triggered inflammation (TRUE)

E. motility is afforded by bacterial surface flagella, which contain PAMPs recognised by TLR5 (TRUE)

Question 491

In bacterial infection

A. Legionella pneumophila causes propagated outbreaks of pneumonic Legionnaires’ disease initiated by droplets from air-conditioning units 

B. Pseudomonas aeruginosa is an antibiotic-resistant ‘opportunistic’ pathogen e.g. of burns and lungs of cystic fibrosis patients 

C. Chlamydia trachomatis causes non-gonococcal urethritis. It has less than 100 genes and is an obligate intracellular parasite 

D. pharyngitis is caused by Gram-positive Streptococcus pyogenes, which is Lancefield group A based on cell surface carbohydrate 

E. Clostridium botulinum causes flaccid paralysis due to its enzymatic toxin, a protease that prevents exocytosis of acetylcholine by cleaving synaptobrevin 

Answer 491

In bacterial infection

A. Legionella pneumophila causes propagated outbreaks of pneumonic Legionnaires’ disease initiated by droplets from air-conditioning units (FALSE)

B. Pseudomonas aeruginosa is an antibiotic-resistant ‘opportunistic’ pathogen e.g. of burns and lungs of cystic fibrosis patients (TRUE)

C. Chlamydia trachomatis causes non-gonococcal urethritis. It has less than 100 genes and is an obligate intracellular parasite (FALSE)

D. pharyngitis is caused by Gram-positive Streptococcus pyogenes, which is Lancefield group A based on cell surface carbohydrate (TRUE)

E. Clostridium botulinum causes flaccid paralysis due to its enzymatic toxin, a protease that prevents exocytosis of acetylcholine by cleaving synaptobrevin (TRUE)

Question 492

Regarding antibiotic resistance

A. resistance to trimethoprim, an inhibitor of folate synthesis, is conferred by a bacterial ‘bypass’ dihydrofolate reductase

B. penicillin binding to bacterial transpeptidase is prevented by beta- lactamases that cleave the antibiotic 

C. chloramphenicol blocks host cell translation, but resistance follows modification of the ribosome by a bacterial acetyl transferase 

D. in multidrug resistance efflux pumps of Gram-negative pathogens, antibiotics are pumped across the inner membrane in an energy- dependent manner

E. vancomycin mimics D-Ala-D-Ala crosslinks to prevent peptidoglycan crosslinking, but variant bacterial transpeptidases make vancomycin-resistant peptide crosslinks 

Answer 492

Regarding antibiotic resistance

A. resistance to trimethoprim, an inhibitor of folate synthesis, is conferred by a bacterial ‘bypass’ dihydrofolate reductase (TRUE)

B. penicillin binding to bacterial transpeptidase is prevented by beta- lactamases that cleave the antibiotic (TRUE)

C. chloramphenicol blocks host cell translation, but resistance follows modification of the ribosome by a bacterial acetyl transferase (TRUE)

D. in multidrug resistance efflux pumps of Gram-negative pathogens, antibiotics are pumped across the inner membrane in an energy- dependent manner (TRUE)

E. vancomycin mimics D-Ala-D-Ala crosslinks to prevent peptidoglycan crosslinking, but variant bacterial transpeptidases make vancomycin-resistant peptide crosslinks (FALSE)

Question 493

Properties of whipworm (Trichuris trichuria) infection include

A. a human oral-faecal route of infection 

B. eggs shed in the faeces that are immediately infective 

C. a high frequency of rectal prolapse in individuals with a high (>300) egg count 

D. morbidity that is more common in children than adults 

E. an infection that may last for decades 

Answer 493

Properties of whipworm (Trichuris trichuria) infection include

A. a human oral-faecal route of infection (TRUE)

B. eggs shed in the faeces that are immediately infective (FALSE)

C. a high frequency of rectal prolapse in individuals with a high (>300) egg count (TRUE)

D. morbidity that is more common in children than adults (TRUE)

E. an infection that may last for decades (TRUE)

Question 494

The pork tapeworm Taenia solium

A. can be meters long

B. is hermaphroditic (both male and female) 

C. uses pigs as the definitive host 

D. forms cysticerci (or cystercerci) in the intermediate host 

E. may cause epilepsy

Answer 494

The pork tapeworm Taenia solium

A. can be meters long (TRUE)

B. is hermaphroditic (both male and female) (TRUE)

C. uses pigs as the definitive host (FALSE)

D. forms cysticerci (or cystercerci) in the intermediate host (TRUE)

E. may cause epilepsy (TRUE)

Question 495

Human schistosomiasis

A. causes both bladder and intestinal disease 

B. may cause liver fibrosis and calcification due to larval worm migration

C. results in severe immunopathology due to inflammation caused by secretion of adult worm antigens 

D. is a risk factor for bladder cancer 

E. results in blood in urine 

Answer 495

Human schistosomiasis

A. causes both bladder and intestinal disease (TRUE)

B. may cause liver fibrosis and calcification due to larval worm migration (FALSE)

C. results in severe immunopathology due to inflammation caused by secretion of adult worm antigens (FALSE)

D. is a risk factor for bladder cancer (TRUE)

E. results in blood in urine (TRUE)

Question 496

Human leishmaniasis in the New World (Americas) may be caused by

A. a parasite that was originally from the Old World 

B. a parasite that uses humans as the definitive host 

C. parasites that are normally associated with a small range of animal hosts that have now become established in the human population

D. parasites that use more than one mosquito host to extend their geographic range

E. a parasite that lives in macrophages 

Answer 496

Human leishmaniasis in the New World (Americas) may be caused by

A. a parasite that was originally from the Old World (TRUE)

B. a parasite that uses humans as the definitive host (FALSE)

C. parasites that are normally associated with a small range of animal hosts that have now become established in the human population (TRUE)

D. parasites that use more than one mosquito host to extend their geographic range (FALSE)

E. a parasite that lives in macrophages (TRUE)

Question 497

Toxoplasma gondii

A. infects virtually all warm blooded animals 

B. replicates in nucleated cells 

C. drives motility and host cell invasion through an actin-myosin motor complex 

D. may use rhoptry secreted kinases to protect the parasitophorous vacuole from destruction by mouse Immunity Related GTPases 

E. may cause fatal encephalitis due to reactivation of the tissue cyst bradyzoites into rapidly dividing tachyzoites 

Answer 497

Toxoplasma gondii

A. infects virtually all warm blooded animals (TRUE)

B. replicates in nucleated cells (TRUE)

C. drives motility and host cell invasion through an actin-myosin motor complex (TRUE)

D. may use rhoptry secreted kinases to protect the parasitophorous vacuole from destruction by mouse Immunity Related GTPases (TRUE)

E. may cause fatal encephalitis due to reactivation of the tissue cyst bradyzoites into rapidly dividing tachyzoites (TRUE)

Question 498

Malaria caused by Plasmodium falciparum

A. involves a cryptic parasite stage that may cause recurrence of disease decades after the initial infection 

B. is characterised by a small amplification of the parasite in the liver 

C. involves rosetting and sequestration of infected red blood cells 

D. is characterized by schizonts readily observed in a blood smear 

E. is observed in human populations with a high frequency of Duffy- negative individuals 

Answer 498

Malaria caused by Plasmodium falciparum

A. involves a cryptic parasite stage that may cause recurrence of disease decades after the initial infection (FALSE)

B. is characterised by a small amplification of the parasite in the liver (FALSE)

C. involves rosetting and sequestration of infected red blood cells (TRUE)

D. is characterized by schizonts readily observed in a blood smear (FALSE)

E. is observed in human populations with a high frequency of Duffy-negative individuals (FALSE)

Question 499

A myocardial infarct

A. occurs more commonly in the right ventricle than the left ventricle 

B. may lead to fibrinous pericarditis

C. induces granulation tissue 

D. may cause an aneurysm 

E. is typically haemorrhagic during the first 24 hours 

Answer 499

A myocardial infarct

A. occurs more commonly in the right ventricle than the left ventricle (FALSE)

B. may lead to fibrinous pericarditis (TRUE)

C. induces granulation tissue (TRUE)

D. may cause an aneurysm (TRUE)

E. is typically haemorrhagic during the first 24 hours (FALSE)

Question 500

Ischaemia

A. may follow a generalised type-1 hypersensitivity reaction 

B. is more likely to occur in sickle cell anaemia 

C. always causes coagulative necrosis 

D. can lead to death of skeletal muscle within 20 minutes 

E. is a complication of malaria 

Answer 500

Ischaemia

A. may follow a generalised type-1 hypersensitivity reaction (TRUE)

B. is more likely to occur in sickle cell anaemia (TRUE)

C. always causes coagulative necrosis (FALSE)

D. can lead to death of skeletal muscle within 20 minutes (FALSE)

E. is a complication of malaria (TRUE)