Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NBDE 1 > Day 3.1.2 > Flashcards

Day 3.1.2 Flashcards

0
Q

How much iron does the human body contain?

A

4-5 grams

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

What is quantitatively the most important trace element?

A

Iron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the two major ways in which iron is present in the body?

A
  1. Protein-bound in blood

2. Intercellular iron-protein complexes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the only form of iron that can be absorbed by the bowel?

A

Bivalent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What % of the total amount of iron is found in heme proteins?

A

75%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the heme proteins responsible for binding the majority of the iron in blood?

A

Hemoglobin

Myoglobin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the intercellular iron-protein complexes responsible for storing iron?

A

Ferritin

Hemosiderin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Apart from blood, where is iron stored in the body?

A

Liver
Spleen
Bone marrow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is Hemosiderin composed of?

A

A complex of

  1. Ferritin
  2. Denatured ferritin
  3. Other proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What part of the GIT is responsible for the absorption of iron?

A

Upper part of small intestine - mainly duodenum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What way is iron transported in the blood?

A

As part of transferrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the formative components of transferrin?

A

Apotransferrin

Ferrous iron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What type of protein is apotransferrin?

A

Beta globulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What kind of binding does iron have in transferrin?

A

Loose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where is the majority of excess iron stored in the body?

A

Liver - 60%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is storage iron?

A

Iron stored in ferritin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What promptes iron uptake?

A

Reducing agents like ascorbate (vitamin C)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Why is iron uptake increased by reduce agents in blood?

A

Because iron is only absorbed in bivalent form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the dominant factor controlling absorption of iron from the GI tract?

A

Saturation of the mucosal cells with iron - this is controlled by the rate at which the transferrin complex can exit the epithelial complex into the vascular system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Hemochromatosis

A

Iron storage disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Characteristic signs of hemochromatosis

A

Bronzing of skin
Diabetes
Weakness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the pathophysiology of hemochromatosis?

A

Inability to store iron results in the deposition of iron-containing pigments in peripheral tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is bilirubin

A

A product of heme degradation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What blood type is the universal donor?

A

O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why is type O the universal donor?

A

Type O people do not produce AB antigens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What blood type is the universal recipient?

A

AB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Why is type AB the universal recipient?

A

They do not make any AB antibodies so they do not discriminate against any other OAB blood type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What kind of bonds does oxygenate to bind with hemoglobin?

A

It honda loosely with one or the so called coordination bonds of the iron atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How is the gaseous tension of oxygen in peripheral tissue capillaries compared to in the lungs?

A

Much lower

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How many states does hemoglobin exist in?

A

Two conformational states -

T - tense
R - relaxed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Which state of hemoglobin has stronger affinity for oxygen?

A

R conformation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the difference in affinities to oxygen of the two forms of Hb?

A

R conformation of Hb has a 150-300 fold increase of oxygen affinity over the T conformation of Hb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Where do you find the T conformation of Hb?

A

Peripheral capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Where do you find the R conformation of Hb?

A

Lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What determines whether Hb binds with or releases O2?

A

Oxygen partial pressure (PO2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the relationship of PO2 with affinity of Hb for oxygen?

A

Directly proportional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Where is po2 high?

A

Pulmonary capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Where is po2 low?

A

Tissue capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What does the oxyhemoglobin dissociation curve illustrate?

A

The relationship between PO2 in the blood and the number of O2 molecules bound to Hb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What does a shift of the oxyhemoglobin curve to the right indicate?

A

Decreased affinity of Hb for O2

Enhanced O2 dissociation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is p50?

A

The point on the oxyhemoglobin dissociation curve where 50% of Hb is saturated with O2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is p50 in normal adults?

A

27mm Hg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What does a shift of the oxyhemoglobin dissociation curve to the right do to p50?

A

Increases the p50

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What does increase in CO2 do to the oxyhemoglobin dissociation curve?

A

Shifts it to the right

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Factors that shift oxyhemoglobin dissociation curve to right

A

Increased hydrogen ions (decreased pH)
Increased temperature
Increased BPG (2,3 - biphosphoglycerate)
Increased CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

According to genome, what are the two major types of viruses?

A

ssRNA

dsDNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What are the families of viruses that have the dsDNA genome?

A
  1. Herpesvirus
  2. Adenovirus
  3. Hepadnavirus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What are the families of viruses that contain the ssRNA genome?

A
  1. Paramyxovirus
  2. Picornavirus
  3. Flavivirus
  4. Deltavirus
  5. Calcivirus
  6. Orthomyxovirus
  7. Togavirus
  8. Retrovirus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What kind of genome does paramyxovirus have?

A

SsRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What kind of genome does herpesvirus family have?

A

DsDNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What is the only dsDNA virus that doesn’t have “d” in its name?

A

Herpesvirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What kind of genome do the viruses that cause hepatitis have?

A

All but one (hepatitis B) have ssRNA genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What family do the Hepatitis viruses belong to?

A

All of them belong to different families

A - Picornavirus
B - Hepadnavirus
C - Flavivirus
D - Deltavirus
E - Calicivirus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What is the most common cause of gastroenteritis in children 2 and under?

A

Rotaviruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What is the structure of reoviruses?

A

They have an icosahedral capsid composed of an outer and inner protein shell containing a double stranded segmented genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What is the envelope of reoviruses composed of?

A

Reoviruses are non-enveloped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What kind of nuclear material is contained in reoviruses?

A

dsRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Where do reoviruses replicate?

A

In cytoplasm of human cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Can reoviruses replicate using human enzymes?

A

No - the virion contains an RNA dependent RNA polymerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What is the gastroenteritis virus type B?

A

Rotaviruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

How is rotavirus spread?

A

Fecal oral route

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What age groups does rotavirus affect?

A

Most potent in children under 2

They can affect adults but symptoms are mild or absent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

From where are Rotaviruses absorbed into the system?

A

Small intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What is the cause of Colorado tick fever?

A

Coltivirus (Colorado tick fever virus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

24 hour flu, aka

A

Viral gastroenteritis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Intestinal flu, aka

A

Viral gastroenteritis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

How long does it take to recover from viral gastroenteritis?

A

12-24 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What kind of virus causes the intestinal flu?

A

RNA viruses - NOT influenza virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

How is viral gastroenteritis diagnosed?

A

ELISA on fecal samples

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Characteristic signs of viral gastroenteritis

A

Vomiting
Low grade fever
Diarrhea
Metabolic consequences of water and electrolyte loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What is a major concern in viral gastroenteritis?

A

Dehydration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Can viral gastroenteritis be fatal?

A

Yes in infants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Name the RNA non-enveloped virus families

A

Picornavirus
Reovirus
Calicivirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What virus causes many respiratory infections in epidemics each winter?

A

Respiratory syncytial virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

What virus is a common cause of bronchiolitis in infants?

A

Respiratory syncytial virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

Name the envelope components in paramyxoviruses

A

Glycoproteins - hemagglutinin, neuraminidase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

What viruses make up the paramyxovirus family?

A

Measles
Mumps
Parainfluenza
Respiratory syncytial virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

Which of the paramyxoviruses are enveloped?

A

Measles
Mumps
Parainfluenza virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

How is respiratory syncytial virus different from other paramyxoviruses?

A

It doesn’t have envelope glycoproteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

What does respiratory syncytial virus have instead of envelope glycoproteins?

A

Surface spikes - made of fusion (F) proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

What do paramyxovirus spikes contain?

A

Hemagglutinin
Neuraminidase
Fusion protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

What do the fusion proteins in spikes of the paramyxoviruses do?

A

Cell fusion

Hemolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

What is the name of the vaccine for respiratory syncytial virus?

A

There is no vaccine for respiratory syncytial virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

What gave rise to the name of respiratory syncytial virus?

A

The multinucleated giant cells formed due to fusion of infected cells because of virion surface proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

Treatment of respiratory syncytial virus

A

Aerosolized Ribavirin (virazole) in severe cases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

When is intervening treatment indicated in a respiratory syncytial virus infection?

A

Severe cases with underlying cardiac or respiratory disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

What is the reason for possibility of reinfection by RSV throughout life?

A

Antigenic drift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

Conditions caused by parainfluenza viruses

A

Children -
Croup
Pneumonia

Adults - common cold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

Croup

A

Acute laryngotracheobronchitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

What do the surface spikes on parainfluenza viruses consist of?

A

Hemagglutinin
Neuraminidase
Fusion proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

How are parainfluenza viruses transmitted?

A

Respiratory droplets

Direct contact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

How are conditions caused by parainfluenza viruses treated?

A

No antiviral therapy or vaccine is available

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

Which members of the paramyxovirus family cause viremia?

A

Measles

Mumps viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

What is most characteristic of a viral pneumonia?

A

Interstitial pulmonary inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

What kind of nuclear material do paramyxoviruses have?

A

Ss negative RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

Which ones are larger - Ortho or paramyxoviruses?

A

Paramyxoviruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

What is the difference between the genomes of para and orthomyxoviruses?

A

Paramyxoviruses have nonsegmented genomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

What is the hallmark of viral infection?

A

Cytoplasmic effect (CPE)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
98
Q

Chronology of events in cytopathic effect

A

Alterations of cell morphology
Marked derangement it cell function

Culminate in lysis and death of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
99
Q

List cytopathic changes

A 
Necrosis
Hypertrophy
Giant cell formation
Hypoplasia
Metaplasia
Altered shape
Detachment from substrate
Lysis
Membrane fusion
Altered membrane permeability
Inclusion bodies
Apoptosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
100
Q

What is the use of knowing cytologic changes?

A

They provide useful presumptive evidence for diagnosis of the viruses that induce cytopathic changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
101
Q

How do viruses gain entry into host cells?

A

They use specific cell surface receptors to bind to and subsequently gain entry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
103
Q

What does the use of specific cell surface receptors explain about viruses?

A

Cellular tropism of viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
104
Q

What family are Coxsackie viruses a part of

A

Picornavirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
105
Q

What are the characteristics of picornavirus family

A

ssRNA
icosahedral capsid
no envelope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
106
Q

What are the differences between different herpesviruses?

A

They are all identical morphologically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
107
Q

What are the common characteristics of herpesviruses?

A

dsDNA
enveloped
nuclear membrane
icosahedral nucleocapsid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
108
Q

What is the major defining characteristic of herpesviruses?

A

They obtain their virion envelopes by budding from the host nuclear or golgi membrane instead of the host plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
109
Q

Where do herpesviruses replicate?

A

In the nucleus of the host cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
110
Q

What is the hallmark of all herpesvirus infections

A

the ability of the viruses to establish latent infections that persist for the life of the individual

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
111
Q

Which herpesvirus remains latent in the trigeminal ganglion?

A

HSV-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
112
Q

Where does HSV-2 most commonly remain dormant?

A

Sacral ganglia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
113
Q

Which virus remains latent in dorsal root and cranial nerve ganglia?

A

VZV - Varicella zoster virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
114
Q

Where does CMV remain latent?

A

Nuclei of cells in the endothelium of the arterial wall and in T lymphocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
115
Q

Which virus remains latent in resting memory B lymphocytes?

A

EBV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
116
Q

Which of the herpesviruses cause a vesicular rash?

A

HSV 1, 2 and VZV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
117
Q

What Herpesviruses have oncogenic potential in humans?

A

EBV

HSV-8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
118
Q

What virus is associated with Burkitt’s lymphoma?

A

EBV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
119
Q

What cancers is EBV associated with in humans?

A
  • Burkitt’s lymphoma

- Nasopharyngeal carcinoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
120
Q

HSV - 8 aka

A

Kaposi’s sarcoma-associated herpesvirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
121
Q

What virus is associated with Kaposi’s sarcoma?

A

HSV - 8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
122
Q

What kinds of Kaposi’s sarcoma are associated with HSV 8?

A
  • Classical

- AIDS related

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
123
Q

List of DNA Enveloped viruses

A

Herpesvirus
Posxvirus
Hepadnavirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
124
Q

Prions

A

Most recently recognised

Simplest infectious agents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
125
Q

What is the molecular structure of a prion

A

a single protein molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
126
Q

What kind of nucleic acid do prions contain

A

None

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
127
Q

What kind of genetic info do prions contain?

A

None

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
128
Q

What disease do prions cause?

A

Creutzfeldt-Jakob disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
129
Q

What disease is Creutzfeldt-Jakob disease associated with?

A

Mad Cow disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
130
Q

How is Creutzfeldt-Jakob disease caused?

A

Ingestion of beef from a cow infected with mad cow disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
131
Q

What is the speed of progression of Creutzfeldt Jakob disease in humans?

A

Slow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
132
Q

How does Creutzfeldt-Jakob disease manifest in humans?

A

It is a severe degenerative brain disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
133
Q

How do prions propogate within a host?

A

They induce the conversion of endogenous prion protein PrP into a protease resistant isoform PrP to the power of Sc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
134
Q

How much inflammation do prions cause?

A

None

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
135
Q

What kind of antibodies deal with prions?

A

None

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
136
Q

What does treatment with formalin, heat, radiation do to prions?

A

It does not neutralise them, though it can reduce their infectivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
137
Q

What are the major components of a virion?

A

Nucleic acids
Protein coat
Lipoprotein envelope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
138
Q

What is the capsid?

A

Protein coat of virions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
139
Q

What is a nucleocapsid?

A

Combination of nucleic acid and capsid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
140
Q

What does the presence of a lipoprotein envelope determine

A

Whether a nucleocapsid is naked or enveloped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
141
Q

What is the capsid composed of?

A

Polypeptide units called capsomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
142
Q

What viruses are covered with spikes?

A

Orthomyxoviruses and paramyxoviruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
143
Q

What is the difference between viruses and bacteria, fungi and parasites?

A

Viruses are not cells, cannot reproduce independently, don’t have a nucleus and do not have organelles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
144
Q

Which is bigger, bacteria or viruses?

A

Bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
145
Q

Which can be seen in a light microscope, fungi or viruses?

A

Fungi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
146
Q

Are viruses haploid or diploid?

A

Haploid, except the retrovirus family

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
147
Q

Haploid

A

Contain a single copy of their genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
148
Q

Which are the only diploid viruses?

A

Retrovirus family

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
149
Q

Viroids

A

A single molecule of circular RNA without a protein coat or envelope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
150
Q

What diseases do viroids cause in humans?

A

None

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
151
Q

How is HSV 2 spread?

A

Mainly through sexual contact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
152
Q

Can HSV 2 be spread from mother to newborn during childbirth?

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
153
Q

What kind of lesions does HSV 1 cause?

A

Labial lesions predominantly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
154
Q

Which HSVs cause manifestations of recurrent infection in otherwise healthy people?

A

HSV 1, 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
155
Q

What does HSV 1 cause

A

Primary herptic gingivostomatitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
156
Q

How is Primary herpetic gingivostomatitis caused?

A

Initial exposure to HSV 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
157
Q

How is primary herpetic gingivostomatitis spread?

A

From person to person through oral secretions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
158
Q

What age group is generally affected by primary herpetic gingivostomatitis?

A

Children under 10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
159
Q

Manifestations of primary herpetic gingivostomatitis

A

Generally subclinical

  • flu-like symptoms
  • one or two mild sores in the mouth, generally unnoticed by the parents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
160
Q

What kinds of infections can HSV 1 cause?

A

Primary herpetic gingivostomatitis

Acute herpetic gingivostomatitis

Herpes labialis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
161
Q

Cold sore aka

A

Herpes labialis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
162
Q

Symptoms of acute herpetic gingivostomatitis

A
  • fever
  • irritability
  • cervical lymphadenopathy
  • fiery red gingival tissues
  • small, yellowish vesicles which rupture and result in painful ulcers on free and attached mucosa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
163
Q

What disease shows fiery red gingival tissues in association with yellowish vesicles?

A

Acute herpetic gingivostomatitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
164
Q

What disease manifests as painful ulcers on free and attached mucosa?

A

Acute herpetic gingivostomatitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
165
Q

What is the most serious potential problem in a child with acute herpetic gingivostomatitis?

A

Dehydration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
166
Q

Why is there a risk of dehydration in a child with acute herpetic gingivostomatitis?

A

Due to the child not wanting to eat or drink because of the pain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
167
Q

What is adult recurrence of HSV 1 infection called?

A

Herpes labialis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
168
Q

Symptoms of herpes labialis

A
  • localized parasthesia of the lip

- cold sore

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
169
Q

Most common site of recurrence of HSV 1 in adults

A

Vermilion border of lips

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
170
Q

What is the less common type of recurrent HSV 1 infection

A

Herpetic conjunctivitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
171
Q

What herpes infection can be treated prophylactically by a vaccine?

A

VZV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
172
Q

What diseases does VZV produce?

A
  • Varicella

- Herpes Zoster

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
173
Q

Varicella aka

A

Chickenpox

174
Q

Herpes zoster aka

A

Shingles

175
Q

What is the primary infection of VZV?

A

Varicella

176
Q

How does shingles occur?

A

Reactivation of a latent VZV infection (From the dorsal root and cranial nerve ganglia)

177
Q

What is the vaccine used for VZV?

A

Live attenuated variella vaccine

178
Q

Does VZV vaccine work in adults?

A

Vaccination of all adults over the age of 60 with a dose higher than that used for chickenpox prophylaxis in childhood reduces shingles-related morbidity and post-herpetic neuralgia

179
Q

WHich one infects below the waist - HSV 1 or 2

A

HSV 2 - Genital lesions

180
Q

Which one infects above the waist - HSV 1 or 2?

A

HSV 1 - eye and mouth lesions

181
Q

What kind of HSV lesion can be a result of sexual activity?

A

Oral-genital activity - HSV 1 above the waist and HSV 2 below the waist

182
Q

Complications of HSV 1 infection

A
  • transfer to the eye
  • acute encephalitis
  • skin infections
183
Q

What eye-related complications are caused by HSV 1?

A
  • dendritic ulceration

- keratitis

184
Q

What are the skin infections caused as complications of HSV 1 infection?

A
  • herpetic whitlow

- erythema multiforme

185
Q

How is HSV 1 infection diagnosed?

A

Tzanck preparation of vesicular fluid - shows multinucleated giant cells

186
Q

Treatment of HSV 1 infection

A

Systemic antiviral drugs - acyclovir

  • famciclovir
  • valacyclovir
187
Q

Can HSV 1 be completely treated?

A

No, antiviral therapy is suppressive or episodic

188
Q

What is the effect of HSV 2 infection on pregnant women?

A

It can have serious consequences - the virus can be transmitted to the infant during vaginal delivery

189
Q

What effect does HSV 2 have on infants?

A

Damage to nervous system and/or eyes

190
Q

Temperate phage

A

A bacteriophage with the ability to form a stable, nondisruptive relationship within a bacterium

191
Q

How does a temperate phage replicate?

A

An alternate method in which the phage genome is incorporated into the bacterial chromosome

192
Q

How is a temperate phage different from a virulent phage?

A

It persists through many cell divisions of the bacterium without destroying the host

193
Q

Bacteriophage

A

A virus that can only replicate within specific host bacterial cells

194
Q

What is a bacteria that contains a temperate bacteriophage

A

Lysogenic bacterium

195
Q

Example of a lysogenic bacterium

A

Corynebacterium diphtheriae

196
Q

Lysogenic conversion

A

The alteration of a bacterium to a virulent strain by the transfer of a DNA temperate bacteriophage

197
Q

What is the integrated viral DNA of a bacteriophage called?

A

Prophage

198
Q

What is a phage that infects E coli bacteria called?

A

Enterobacteria phage T4

199
Q

Plasmids

A

Extrachromosomal double stranded circular DNA molecules that are capable of replicating independently of the bacterial chromosome

200
Q

Lysogenic cycle

A

Integration of virus into host genome without killing the host

201
Q

Transduction

A

Transfer of DNA from a donor cell to a recipient cell with the DNA packaged witin a bacteriophage

202
Q

Lytic cycle

A

Viral multiplication within a host cell leading to destruction

203
Q

What does the nucleic acid core of a bacteriophage contain?

A

DNA or RNA

204
Q

Is the core of a bacteriophage single or double stranded?

A

Either

205
Q

Do bacteriophages have the same structure as a virion?

A

They have a protein coat and may be surrounded by lipid

206
Q

How do bacteriophages infect bacterial host cells?

A

Some have a tail like structure through which they inject their nucleic acid into the bacterial host cell

207
Q

Host cell

A

A cell within which a virus replicates

208
Q

What does the virus do within a host cell

A

The viral genome achieves control of the cell’s metabolic activities

209
Q

How does a virus replicate within a host cell?

A

It uses the metabolic capacity of the host cell to reproduce new viruses

210
Q

How does the host cell die when a virus inhabits it?

A

The replication of the new viruses often causes death of the host cell

211
Q

How many courses can bacteriophage infection take in a host cell?

A

Two - lysis or lysogeny

212
Q

When is a virus said to be lytic?

A

When the infecting virus multiplies within the host cell and destroys it

213
Q

What is a lytic virus also called?

A

Virulent

214
Q

When is a virus said to be temperate?

A

When it does not replicate but rather integrates into the bacterial chromosome

215
Q

What is a temperate virus also known as?

A

Lysogenic

216
Q

Can a lytic phage be lysogenic and vice versa?

A

No and yes - a phage in a lysogenic cycle can spontaneously become lytic

217
Q

Can a host cell be infected by other phages when already inhabited by an integrated virus?

A

Not similar phages

218
Q

Prophage

A

An integrated virus in a host bacterial cell

219
Q

Does lysogeny result in destruction of the host cell?

A

no

220
Q

Transformation

A

Gene transfer resulting from the uptake by a recipient cell of naked DNA from a donor cell

221
Q

What is the exchange of genetic material from one bacterial cell to another by close association called?

A

Conjugation

222
Q

What structure does the bacterial chromosome or plasmid pass through during conjugation?

A

F pilus

223
Q

What kind of nucleic material do retroviruses contain?

A

2 identical, single stranded positive sense RNA molecules

224
Q

What is reverse transcriptase

A

An RNA directed DNA polymerase

225
Q

Provirus

A

When reverse transcriptase forms viral DNA from viral RNA and incorporates it into host DNA

226
Q

What does the creation of a provirus do?

A

It provides the template for viral RNA synthesis by host-derived mechanisms

227
Q

How are retroviruses distinguished from other RNA viruses?

A

Their ability to replicate through a DNA intermediate using an enzyme reverse transcriptase

228
Q

Human lymphotrophic retroviruses

A
  • Lentivirus - HIV 1 and 2

- Oncovirus - HTLV 1 and 2

229
Q

What do HIV viruses cause

A

AIDS

230
Q

What is the cause of adult T cell leukemia

A

HTLV 1

231
Q

What does HTLV 2 cause

A

Myelopathy

232
Q

Where does transcription occur for RNA viruses?

A

Cytoplasm

233
Q

What are the exceptions for transcription occurring in the cytoplasm for RNA viruses?

A

Retroviruses

Influenza viruses

234
Q

What does transcription depend on in RNA viruses?

A

An RNA dependent RNA polymerase

235
Q

What RNA virus does not depend on an RNA dependent RNA polymerase?

A

Retroviruses - RNA directed DNA polymerase - Reverse transcriptase

236
Q

Where does transcription occur in DNA viruses?

A

Nucleus

237
Q

Which DNA virus does not have transcription occuring in the nucleus

A

Poxviruses

238
Q

What enzyme does transcription in DNA viruses involve?

A

A host cell DNA dependent RNA polymerase

239
Q

Which type of viruses have transcription occurring in cytoplasm?

A

RNA viruses

240
Q

What is the primary disease caused by EBV?

A

Infectious mononucleosis

241
Q

What are the secondary diseases associated with EBV?

A

Burkitt’s lymphoma
B cell lymphoma
Hairy leukoplakia
Nasopharyngeal carcinoma

242
Q

Diseases associated with CMV

A

Congenital infection - if the mother becomes infected with CMV during pregnancy

INfection in immunocompromised individuals

243
Q

What cells do human adenoviruses prefer for replication?

A

Epithelial cells

244
Q

What system are human adenoviruses unlikely to target?

A

Central nervous system

245
Q

What kind of a genome do human adenoviruses have?

A

Double stranded linear DNA genome

246
Q

What is the morphology of human adenoviruses?

A

Naked (non-enveloped), medium sized, composed of anicosahedral nucleocapsid

247
Q

What are the spikes of adenoviruses made of?

A

Glycoproteinaceous projections that are hemagglutinin proteins

248
Q

What do the spikes help do in adenoviruses?

A

They are involved in the adsorption or attachment of the virus to epithelial derivatives of the host

249
Q

What kind of infections do adenoviruses cause?

A

Subclinical infections

250
Q

How are adenovirus infections transmitted?

A

Droplets of respiratory or ocular secretions

251
Q

What diseases are caused by adenoviruses?

A 
Respiratory illnesses in children
Conjunctivitis
Gastrointestinal disease
UTIs
Pharyngitis
252
Q

What is the capsid composed of in a virus?

A

Repeating protein subunits

253
Q

What are protomers?

A

Repeating protein subunits that form capsids

254
Q

What part of the virus protects the viral genome?

A

Capsid

255
Q

What does the capsid protect the viral genome from?

A

Proteases

256
Q

What imparts structural symmetry to the virion?

A

Capsid

257
Q

What kinds of structural symmetry does the virion have?

A

2 -

  • icosahedral
  • helical
258
Q

What role does the capsid play in infectivity of the virion?

A

It is essential for the infectivity

259
Q

What role does the capsid play in naked viruses?

A

Attachment protein that binds to the host cell receptor

260
Q

How do hosts react to the capsid?

A

Capsid is antigenic and provokes host immune response

261
Q

How many capsids to viruses have?

A

One - the only exception is retroviridae - two capsids

262
Q

Matrix protein

A

Welds the capsid or nucleocapsid to the envelope

263
Q

Envelope

A

Viral membrane

264
Q

What is the envelope composed of

A

Lipid bilayer carrying viral glycoproteins

265
Q

What viral antigens are of diagnostic value?

A

Proteins

266
Q

What family of viruses is responsible for polio?

A

Picornaviruses

267
Q

What human-infecting viruses are included in picornaviruses?

A
  • enteroviruses
  • rhinoviruses
  • Hep A virus
268
Q

What does the term entero mean in enteroviruses?

A

Enteric means of spread of these viruses - via the fecal-oral route

269
Q

What do enteroviruses include?

A

Poliovirus types 1-3
Coxsackie A and B
Echoviruses
Enteroviruses 68-71

270
Q

What does the poliovirus cause?

A

Poliomyelitis

271
Q

What is the structure of the poliovirus?

A

Very small
single stranded positive RNA virus
Icosahedral capsid
No envelope

272
Q

Where does the poliovirus replicate?

A

It preferentially replicates in the motor neurons of the anterior horn of the spinal cord

273
Q

What is the result of the replication of polioviruses in their preferred site?

A

Death of the motor neurons of the anterior horn of the spinal cord - leading to muscle paralysis

274
Q

How is poliovirus transmitted?

A

Consumption of water with fecal contaminants

275
Q

Is poliovirus common in the western world?

A

No, because of successful vaccination programs

276
Q

Initial symptoms of poliomyelitis

A

Headache
Vomiting
Constipation
Sore throat

277
Q

What follows the initial symptoms of poliomyelitis?

A

Paralysis which is asymmetric and flaccid

278
Q

How many vaccines are used for poliomyelitis?

A

Two

279
Q

What kind of immunization do polio vaccines provide?

A

Active immunization

280
Q

Name the two vaccines used against poliomyelitis

A

Salk

Sabin

281
Q

Salk vaccine composition

A

Formalin-treated inactivated viruses

282
Q

How is salk vaccine delivered

A

IV

283
Q

Sabin vaccine composition

A

Live attenuated viruses

284
Q

How is sabin vaccine delivered

A

Orally

285
Q

How many types of polio virus do the vaccines contain?

A

3 - trivalent

286
Q

Largest and most complex DNA virus

A

Poxvirus family

287
Q

How many viruses of medical importance does the poxvirus family include?

A

3 -
Smallpox virus (variola virus)
vaccinia virus
Molluscum contagious virus (MCV)

288
Q

What is the general morphology of poxviruses?

A

Complex, oval to brick-shaped morphology with internal structure

289
Q

smallpox virus aka

A

variola virus

290
Q

What are the dimensions of the poxviruses?

A

300nm x 200nm (very large)

291
Q

What does the viral genome of poxviruses contain?

A

A large, double stranded, linear DNA that is fused at both ends.

292
Q

Where do poxviruses multiply?

A

Cytoplasm of host cells - unusual of DNA viruses which usually multiply in the nucleus

293
Q

Which is the most important human poxvirus?

A

Smallpox (variola)

294
Q

What symptom is associated with poxviruses?

A

Skin rashes

295
Q

What is smallpox characterised by?

A

High fever
Prostration
A vesicular, pustular rash

296
Q

Smallpox is

A

An acute, highly infectious, often fatal disease

297
Q

How was smallpox eradicated?

A

Global use of the vaccine

298
Q

What does the smallpox vaccine contain?

A

Live attenuated vaccinia virus

299
Q

What enzyme does the virion of poxviruses contain?

A

DNA Dependent RNA polymerase

300
Q

Why do poxviruses need DNA dependent RNA polymerase?

A

They replicate in the cytoplasm, and hence do not have access to the cellular RNA polymerase which is located in the nucleus

301
Q

How many serotypes does the smallpox virus have?

A

A single stable serotype

302
Q

What is the key to the success of the vaccine against smallpox?

A

The presence of a single stable serotype

303
Q

What would have caused failure of eradication of smallpox?

A

A varied antigenicity like that of influenza

304
Q

Name icosahedral DNA viruses other than the poxviruses

A

Herpesviruses
Adenoviruses
Papovaviruses
Hepadnavirus

They multiply in the nucleus of the host cells

305
Q

Which are the only DNA viruses that replicate in the cytoplasm of the host cell?

A

Poxviruses

306
Q

Members of the picornaviridae family

A 
Poliovirus
Coxsackie virus
Enterovirus
Hep A virus
Rhinovirus
307
Q

Name a large family of small viruses

A

Picornaviruses - Small = 30nm viruses

308
Q

Structure of picornaviruses

A

Non-enveloped
Single stranded positive RNA genome
Icosahedral capsid

309
Q

What is peculiar about picornaviruses?

A

They are incapable of causing cell transformation due to the RNA genome

310
Q

Why can’t picornaviruses cause cell transformation?

A

RNA genome

311
Q

What virus causes herpangina and hand-foot-and-mouth disease?

A

Coxsackie Group A viruses

312
Q

How do you distinguish between herpangina and hand-foot-and-mouth disease?

A

Oral lesion locations

313
Q

When oral lesions are located on the throat, palate or tongue, what kind of Coxsackievirus disease is it?

A

Herpangina

314
Q

What kind of Coxsackie viral disease causes lesions to appear on the buccal mucosa and gingiva?

A

Hand-foot-and-mouth disease

315
Q

What are the manifestations of diseases caused by the Coxsackie Group A virus?

A

Vesicular lesions (location defines specific disease)

  • fever
  • sore throat
  • pain on swallowing
316
Q

How does Coxsackie Group B virus get its name?

A

B for body

317
Q

What are the manifestations of disease with Coxsackie group B virus?

A

Chest pain with headache
Fatigue
Aching muscles lasting 4-5 days

318
Q

Diseases associated with echoviruses

A 
Aseptic meningitis
Encephalitis
Paralysis
Rash
Fever
Acute URTIs
Enteritis
Pleurodynia
Myocarditis
Neonatal infections
319
Q

What is the main cause of the common cold?

A

Rhinoviruses

320
Q

How many serologic types of rhinoviruses exist?

A

> 100

321
Q

What is the main reason that a vaccine hasn’t been found for the common cold yet?

A

There are > 100 serologic types of rhinoviruses present

322
Q

What virus family is EBV part of?

A

Herpesvirus

323
Q

What is oral hairy leukoplakia?

A

A whitish, nonmalignant lesion on the tongue

324
Q

What disease is oral hairy leukoplakia especially associated with?

A

AIDS

325
Q

What virus is associated with oral hairy leukoplakia?

A

EBV

326
Q

What is EBV associated with the development of?

A

Burkitt’s lymphoma

Nasopharyngeal ca

327
Q

What kind of cells does EBV specifically infect?

A

B lymphocytes

328
Q

Does EBV remain latent?

A

Yes - in resting memory B lymphocytes after primary infection

329
Q

What is a highly diagnostic test for EBV?

A

Heterophile test

330
Q

Heterophile test aka

A

Mononucleosis spot test

331
Q

Lab findings of mononucleosis

A

Lymphocytosis
presence of atypical lymphocytes
IgM heterophile antibodies

332
Q

What does the heterophile test do?

A

Identifies IgM heterophile antibodies

333
Q

How many patients show a positive result in the heterophile test?

A

80% of those with infectious mononucleosis

334
Q

Rubella aka

A

German measles

335
Q

Cause of rubella

A

Spherical, enveloped RNA virus

336
Q

How is Rubella virus spread?

A

Droplets

337
Q

Characteristic presenting signs of German measles

A
  • Characteristic rash - flat pink spots on the face that spread to other body parts
338
Q

Characteristic presenting sign of Measles

A

Koplik’s spots

339
Q

Measles aka

A

rubeola

340
Q

Where are Koplik’s spots found?

A

Oral cavity, opposite molars

341
Q

Describe the nature of Koplik’s spots

A 
Small
Bluish white lesions
Surrounded by a red ring
Cannot be wiped off
Occur opposite molars
342
Q

Koplik’s spots

A

Found in measles

343
Q

Paramyxoviruses

A

Heterogenous group of enveloped viruses with negative ssRNA genomes

344
Q

Enlargement of parotid glands is seen in …

A

Mumps

345
Q

Serious complications of mumps

A

Deafness in children

Orchitis in males past puberty

346
Q

Orchitis

A

inflammation of the testis

347
Q

Causes of parainfluenza

A

Parainfluenza viruses types I-IV

348
Q

What do Parainfluenza viruses cause?

A

Acute respiratory disease

349
Q

MMR vaccine is used for

A

Measles mumps and rubella

350
Q

What does MMR vaccine contain

A

Three live attenuated virus

351
Q

How is MMR vaccine administered

A

Via injection

352
Q

What is the schedule of administration of MMR vaccine?

A

1 year old - first dose

Before starting school (age 4/5) - Booster dose

353
Q

What does the word retro in retroviruses refer to?

A

The possession of the enzyme reverse transcriptase

354
Q

What does reverse transcriptase do?

A

It transcribes RNA to DNA during the process of viral nucleic acid synthesis

355
Q

Why are HIV 1 and HIV 2 classified as lentiviruses?

A

Because of their slowly progressive clinical effects

356
Q

What is reverse transcriptase?

A

An RNA directed DNA polymerase

357
Q

What does the nucleocapsid of HIV consist of?

A

2 single strands of RNA along with 3 enzymes, all encased in an outer lipid envelope

358
Q

What are the enzymes contained in HIV?

A

Reverse transcriptase
Protease
Integrase

359
Q

What is the lipid envelope of HIV derived from?

A

A host cell

360
Q

How is the lipid envelope of HIV derived?

A

It is derived from a host cell via budding

361
Q

How many surface projections does the envelope of HIV have?

A

72

362
Q

What do the surface projections of the HIV envelope contain?

A

An antigen - gp120

363
Q

What does the antigen in the surface projections of HIV do?

A

The antigen - gp120 - aids in the binding of the virus to the target cells with CD4 receptors

364
Q

Are there other proteins apart from gp120 in the envelope?

A

Yes - gp41 - it binds gp120 to the lipid envelope

365
Q

How many major genes does the genome of HIV contain?

A

3

366
Q

How many major genes do the genomes of retroviruses contain?

A

3

367
Q

What are the major genes in the genome of HIV?

A
  • env gene
  • pol gene
  • gag gene
368
Q

What is the gene in HIV that codes for the envelope glycoproteins?

A

env gene

369
Q

What gene in HIV codes for its enzymes?

A

pol gene

370
Q

What does the gag gene do in HIV?

A

Codes for the core proteins

371
Q

How does transmission of HIV occur?

A

Sexual contact

Transfer of infected blood

372
Q

What is the action of HIV in the body?

A

IT infects and kills Helper CD4 T-cells

373
Q

What is the effect of the death of helper CD4 T-cells?

A

Depression of both humoral and cell-mediated immunity

374
Q

What kind of immunity does HIV target?

A

Both humoral and cell-mediated immunity

375
Q

Which are the first cells to be infected by HIV?

A

Macrophages

376
Q

What distinctive action does HIV have on cells?

A

It has a distinctive CPE - cytopathic effect - called giant cell (syncytial) formation

377
Q

What kinds of receptors are required for HIV to infect cells?

A
  • CD4 receptor

- Chemokine (a core receptor)

378
Q

What is the reason for rapid emergence of new strains of HIV?

A

Frequent errors introduced by viral reverse transcriptase

379
Q

How does Acute HIV 1 primary infection present?

A

A mononucleosis-like syndrome

  • fever
  • fatigue
  • sore throat
  • skin rash
380
Q

How does HIV differ from RNA tumor viruses?

A

It lyses host cells

381
Q

What are the other retroviruses apart from HIV?

A

HTLV 1 and 2, classified as oncoviruses.

382
Q

Name 3 types of viruses that contain negative sense RNA

A

Orthomyxoviruses
Paramyxoviruses
Rhabdoviruses

383
Q

What kind of RNA polarity do retroviruses have?

A

Positive polarity

384
Q

What does positive sense RNA molecule mean?

A

RNA with the same base sequence as mRNA

385
Q

What kind of base sequence does RNA with negative polarity have?

A

one that is complementary to mRNA

386
Q

What kinds of viruses does the term positive and negative polarity refer to?

A

RNA viruses

387
Q

What is the first step in viral gene expression?

A

mRNA synthesis

388
Q

What is the difference in mRNA synthesis faced by positive and negative sense RNA viruses?

A

Positive polarity RNA viruses can use their RNA genome directly as mRNA

389
Q

What do negative polarity RNA viruses have that positive polarity RNA viruses don’t?

A

Their own RNA dependent RNA polymerase - as host cells do not have an RNA polymerase capable of using RNA as a template

390
Q

What can be the structural variations in an RNA virus genome?

A

They can be single stranded or double stranded, segmented or non-segmented.

391
Q

What is the age group most affected by varicella?

A

Varicella aka chickenpox - 90% of all cases are in children under 9 years of age

392
Q

Presentation of varicella

A

Local lesions (vesicles) in skin after dissemination of virus through the body;

The lesions become encrusted and fall off in a week

393
Q

What does aspirin administration do during childhood viral infections?

A

Increases the incidence of Reye’s syndrome

394
Q

What is Reye’s syndrome

A

It can cause encephalitis and liver impairment

395
Q

How does shingles present?

A

Shingles (herpes zoster) presents as painful vesicles on skin or mucosal surfaces along distribution of a sensory nerve

396
Q

In what kind of patients is shingles more common?

A

Immunocompromised individuals

397
Q

Is shingles localised?

A

Yes - to a single dermatome

398
Q

Adenosine arabinoside aka

A

vidarabine

399
Q

What suppresses the synthesis of varicella zoster and HSVs?

A

Adenosine arabinoside

400
Q

What tends to diminish new lesion formation and duration of fever in VZV infections?

A

vidarabine

401
Q

What does vidarabine do to VZV spread?

A

it prevents the spread of the virus through the viscera.

402
Q

What family do influenza viruses belong to?

A

Orthomyxovirus family - they are the only members of this family

403
Q

Composition of influenza virus

A

Unique segmented, negative, ssRNA genome

404
Q

Shape of influenza virus

A

Spherical or filamentous enveloped virus

405
Q

Types of influenza virus

A

3 - A, B, C

406
Q

How are the three types of influenza viruses distinguished?

A

The nature of their internal proteins

407
Q

What kind of influenza virus is responsible for pandemics and epidemics?

A

Influenza A

408
Q

What kind of influenza virus causes smaller outbreaks which are localised and milder - such as in camps or schools?

A

Influenza B

409
Q

What does Influenza C cause?

A

Mild Upper respiratory tract illness

410
Q

What kinds of spikes cover the envelope of Influenza viruses?

A

2 - Hemagglutinin, and neuraminidase

411
Q

What is the role of Hemagglutinin spikes?

A

Hemagglutinin is a surface protein and aids attachment of the virus to the cell wall of susceptible host cells at specific receptor sites

412
Q

What part of the influenza virus facilitates cell penetration?

A

Neuraminidase spikes in the envelope

413
Q

How does cell penetration occur in the influenza virus?

A

Pinocytosis and release of replicated viruses from the cell surface effected by budding through the cell membrane

414
Q

What is the ability of the influenza virus to cause epidemics dependent on?

A

Antigenic changes in Hemagglutinin and neuraminidase

415
Q

What kind of changes can happen in hemagglutinin and neuraminidase?

A
  • Antigenic shifts

- Antigenic drifts

416
Q

What are antigenic shifts?

A

Major changes based on reassortment of genome pieces

417
Q

What are antigenic drifts?

A

Minor changes based on point mutations

418
Q

Manifestations of Reye’s syndrome

A
  • Vomiting
  • Lethargy
  • may result in coma.
419
Q

What is the fatality rate of Reye’s syndrome?

A

40%

420
Q

What kind of infections is Reye’s syndrome associated with?

A

Influenza or chickenpox (VZV or Herpes zoster) especially in young children treated with aspirin

421
Q

What medications are not associated with Reye’s syndrome?

A

Acetaminophen

Ibuprofen

422
Q

What is the most noticeable symptom of mumps?

A

painful swelling of the parotid glands - uni or bilateral

423
Q

Other significant complications of mumps

A
  • deafness in children

- orchitis possibly leading to sterility in post-pubertal males

424
Q

What medications can be used in influenza?

A

Amantadine

Rimantadine act to prevent viral replication and are only effective against influenza A

425
Q

What disease presents with flu like symptoms, lymphadenopathy followed by a rash on the entire body?

A

German measles (rubeola)

426
Q

Causative organisms of pharyngitis

A

Adenoviruses

Coxsackieviruses

427
Q

what viruses are spread by arthropod vectors?

A

Arboviruses -

  • Alphaviruses
  • Flaviviruses
428
Q

Name flaviviruses

A

Yellow fever virus
Dengue virus
West Nile virus

429
Q

What family are alphaviruses a member of?

A

Togavirus family

430
Q

What family are rhinoviruses a member of?

A

Picornaviruses

431
Q

What is the structure of rhinoviruses?

A

ssRNA (positive sense) with icosahedral capsid and no envelope

432
Q

Name other agents likely to cause the symptoms of the common cold

A

Enteroviruses
Coronaviruses
Adenoviruses
Parainfluenzaviruses

NBDE 1 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions