I2M Quiz & BOFs Flashcards
1
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The deionised water has no solutes in it, and the comparatively high intracellular concentration of solutes will cause influx of water into the cell, which will cause haemolysis (rupture of blood cells). This leads to a life-threatening situation. Medications that are being administered into the blood and require dilution must be diluted in a saline solution (0.9% NaCl) that has the same osmolarity as plasma. Remember that tonicity compares a solution to the cell, whereas osmolarity compares two solutions.
The correct answer is: Hypotonic
2
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- Osmoreceptors sense the stimulus (increased Na+ concentration of extracellular fluid (increased osmolality) caused by reduced body water) providing an afferent signal to the hypothalamus integrating this with other information and providing an efferent signal to the cortex signalling the desire to drink.
- The stimulus is the (low) blood pressure, the sensor is the baroreceptors (blood pressure detectors), the integrator is the vasomotor centre, the effector is the heart.
- The stimulus is the (low) blood pressure, the sensor is the baroreceptors (blood pressure detectors), the integrator is the vasomotor centre, the effector is the heart, the increased heart rate is the compensatory response (which will help to increase blood pressure).
The correct answer is: 1. Within a homeostatic control system involved in the normal regulation of blood volume through control of thirst, the osmoreceptors in the hypothalamus that detect the osmolality of the internal environment would be classified as: → A sensor, 2. Within a homeostatic control system normally involved in regulating blood pressure, the vasomotor centre in the medulla oblongata of the brain stem that receives input from blood pressure receptors in the circulatory system and provides output to the heart would be classified as: → An integrator, 3. Within a homeostatic control system normally involved in regulating blood pressure, the increase in heart rate that occurs after a blood pressure fall is detected would be classified as: → A compensatory response
3
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- Homeostasis is defined as the maintenance of a relatively stable internal environment (interstitial fluid and blood plasma) in which the cells of the body are bathed.
- Negative feedback is a control mechanism in which a detected change in a regulated physiological variable (in this case BP) initiates physiological changes (reduce heart rate, pumping force and blood vessel diameter) to reverse the direction of change (reduce BP).
- Positive feedback is a control mechanism in which a detected change in a regulated physiological variable (in this case stretch of the cervix as the baby’s head is pushed against it) initiates physiological changes (increased force of contraction of the muscle of the uterus) to increase the direction of change (increase stretch of the cervix).
The correct answer is: 1. The maintenance of a relatively stable internal environment for both Ellen and her baby is an example of: → Homeostasis, 2. As is usual in pregnancy, Ellen has a higher than normal blood volume. When blood pressure rises, a centre in the brain initiates physiological changes to reduce the blood pressure toward normal. This is an example of: → Negative feedback, 3. As Ellen’s labour progresses and delivery begins, the control system that serves to increase force of contractions in response to the stretch of the reproductive tract is: → Positive feedback
4
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The plasma and interstitial fluid make up the extracellular fluid and hence serve as the internal environment of the body. The extracellular fluid compartments differ greatly from the intracellular fluid but plasma and interstitial fluid have almost identical composition of ions (high sodium, high chloride, high bicarbonate, compared to intracellular fluid). The plasma contains high concentrations of the large anions and proteins which cannot pass through the healthy blood vessel wall or cell membrane (intracellular proteins and large anions also in high concentrations), leaving the interstitial fluid almost devoid of these large molecules.
The correct answer is: Large anions
5
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One of the main ways by which heat is lost from the body is across the skin from increase blood flow to the superficial capillaries in the dermal papillae. Blood bypasses these capillaries when the body needs to conserve heat and keep the warm blood more central and not near the skin where heat is lost. This person will undoubtedly be sweating greater than usual, but it is the merocrine/eccrine glands that are responsible for thermoregulation and these open out onto the skin directly, not onto the hair follicle. Sweat is about 99% water, so it is an aqueous solution, not lipid. Adipose tissue plays a role in insulation to keep body heat in, so its role is in relation to warming rather than cooling the body.
The correct answer is: The capillaries in the dermal papillae will have increased blood flow to facilitate heat loss through the skin.
6
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The cells of the Stratum Corneum provide a UV absorbing covering and reduce the amount of radiation that can penetrate the epidermis. Chronic UV exposure results in thickening of the epidermis as a protective mechanism against the damaging effects of UV radiation.
The correct answer is: Thickening of the epidermis
7
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The Golgi apparatus is like the cell’s Post Office – it sorts, “labels” and packages newly synthesised proteins for distribution to various parts of the cell, or export from the cell.
The correct answer is: Golgi apparatus for packaging
8
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Flagella are the whip-like tails of sperm used for propulsion. They are composed of microtubules.
The correct answer is: Sperm cells
9
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Cells with related functions combine to form tissues, groups of tissues with related functions combine to form organs, organs with related functions combine to form body systems.
The correct answer is: Organs
10
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The correct answer is: Wearing appropriate personal protective equipment (PPE)
11
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The correct answer is: Wash hands
12
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Mitochondria are self-replicating organelles present in large numbers in cells which have large energy demands (e.g. muscle cells). The mitochondrial inner membrane folds (cristae) contain the enzyme ATP-synthase which produces ATP from dietary “fuel” molecules such as glucose in a process known as cellular respiration.
The correct answer is: Mitochondria
13
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Evidence Based Medicine (EBM) is the “conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients. The practice of evidence based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research” (Sackett et al. 1996). EBM is a movement which aims to increase the use of high quality clinical research in clinical decision making. The practice of EBM entails a process of life long self- directed learning in which caring for patients creates the need for clinically important information.
The correct answer is: patient values.
14
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Only the RER is involved. The ribosomes, which give the ER the ‘rough’ appearance in the electron microscope, synthesise proteins into the lumen of the ER. In contrast, the smooth ER lacks ribosomes and is therefore not involved in protein synthesis.
The correct answer is: Rough endoplasmic reticulum
15
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The correct answer is: The Clinical waste bin because this could be infected or cause offense if seen
16
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The correct answer is: 1890
17
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The correct answer is: histones.
18
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The correct answer is: The site of modification and transport of proteins in cellular vesicles. → Golgi apparatus, An organelle containing enzymes which degrade molecules including toxic foreign molecules → Lysosome, The site of synthesis of rRNA and the assembly of ribosomes. → Nucleolus
19
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Someone with darker skin has the same number of melanocytes as someone with pale skin, but their activity is greater which means they produce more melanin. Melanin competes with the precursor of Vitamin D for UV absorption. UVB is necessary to convert the vitamin D precursor to the next step in the synthesis pathway for Vitamin D. Someone with repeated sun exposure can have an adaptive thickening of their Stratum Corneum; however, this is limited in terms of how much UV is prevented from penetration further into the epidermis. The thickness of the Stratum Corneum in any individual is not correlated with skin colour or melanocyte activity.
The correct answer is: High levels of melanin compete with the precursor of vitamin D for UV absorption
20
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The correct answer is: Divides the body into left and right sections
21
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The correct answer is: Transport of macromolecules from the cytoplasm
22
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- Acetylcholine acting on muscarinic receptors reduces the heart rate.
- This is a bit of a trick question. The answer is that the response of bronchodilation is mediated by the sympathetic nervous system but the actual chemical mediator responsible for this is epinephrine. This is because the bronchial smooth muscle does not have direct innervation and rather the response is mediated by the circulating epinephrine.
- Contraction of the smooth muscle of the gastrointestinal tract is mediated by acetylcholine acting on muscarinic receptors.
The correct answer is:
- A 25 year old male, who had been running late, is seated and relaxing preparatory to having his blood pressure measured. He notices his pounding heart is slowing. Which chemical mediator is released at the pacemaker region of the heart to reduce the heart rate? → Acetylcholine,
- A 25 year old male hurrying to keep an appointment is breathing quite hard. His airways are dilated, increasing his breathing capacity. Which chemical mediator is most-likely responsible for the bronchiolar smooth muscle relaxation? → Epinephrine,
- A 40 year old female presents with abdominal pain and frequent bowel movements. Which chemical mediator is responsible for stimulating the intestinal smooth muscle to contract and increase gastrointestinal motility? → Acetylcholine
23
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The correct answer is: Central nervous system connected to the periphery by two neurons arranged in series with peripheral ganglia
24
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The correct answer is: Muscarinic receptors that respond to acetylcholine
25
Gap junctions are the simplest type of cell-cell junction. They function to allow communication between cells via transfer of chemical or electrical signals from one cell’s cytoplasm to another through pores made up of connexons. This is particularly important in many tissues such as heart muscle.
The correct answer is: Allow communication between adjacent cells
26
There is no single value for “normal temperature”, rather it is a range of temperatures. With diurnal variation, temperature is lowest in morning. Temperature can be above normal due to heat exposure or similar (hyperthermia) without the hypothalamic set point being reset (fever).
The correct answer is: A range of temperatures subject to diurnal variation
27
1. Blood pressure is regulated from centres in the medulla oblongata in the brain stem. T his includes control of heart rate, blood vessel diameter and heart contractile force. Damage to the vagus nerve would also raise heart rate but this answer is incorrect because the vagus nerve and other cranial nerves are part of the peripheral nervous system.
2. The motor cortex and sensory cortex are implicated with both the face and hand sensation and movement. Cerebellum might have been involved in the movement but not the sensory deficit. The cervical spinal cord may have been implicated in the movement and sensation of the hand but not the face.
3. Poor reflexes and coordination could involve higher centres (cerebellum) however it would be generalised to both arms and legs. Damage to cervical spinal cord might affect spinal reflexes of the arms but not the legs.
The correct answer is: 1. Which major part of the central nervous system might be impaired in controlling his heart rate? → Brain stem medulla, 2. Which major part of the central nervous system might be impaired in a generalised loss of sensation and movement in the hand and face? → Cerebral Cortex, 3. Which part of the central nervous system might be impaired if he exhibits poor reflex responses in the legs but not the arms? → Lumbar spinal cord
28
1. While the Na+/ K+ ATPase is responsible for setting up the transmembrane ion difference essential for establishing a membrane potential, it uses energy in the form of ATP. The resting cell is permeable to only K+ because only the K+ channels are open.
2. Membrane potential is raised by a local voltage change, opening Na+ channels which rapidly enter down both concentration and electrical gradient to initiate the action potential.
3. Nerve conduction is mediated by Na+ and K+ channel opening and closing until the action potential reaches the nerve terminal. Located only in the nerve terminals, Ca2+ channels are opened by depolarisation of the membrane, allowing Ca2+ entry which stimulates transmitter vesicles to merge with the inner membrane and release their contents into the synapse.
The correct answer is: 1. What is the main contributor to ion movement establishing the resting membrane potential of a nerve or other excitable cell that does not require energy? → K+ channel, 2. A change in membrane potential to raise it above threshold for initiating an action potential activates which contributor to ion movement? → Na+ Channel, 3. An action potential conducted to a nerve terminal will stimulate transmitter release triggered by activation of which main contributor to ion movement? → Ca2+ channel
29
Steroid hormones are lipophilic, so are transported in aqueous plasma bound to plasma proteins. The plasma proteins are hydrophilic and so cannot cross cell membranes. Free steroid hormone is the only active form and is able to diffuse easily across the cell membrane and bind to intracellular receptors in the cytosol and nucleus.
The correct answer is: Circulates bound to plasma proteins; free hormone diffuses across cell membrane and binds to intracellular receptors
30
As an excitatory graded potential needs the influx of Na+ not Cl- (causes an inhibitory graded potential), has to reach the axon hillock specifically (not axon terminal) and opens voltage-gated (not chemically-gated) Na+channels = only then does an action potential occur.
The correct answer is: An excitatory graded potential (initiated through the influx of Na+), which reaches membrane threshold at the axon hillock and causes the opening of voltage-gated Na+ channels.
31
High plasma levels of the hormone, but a reduced target tissue response to a standard dose of the hormone shows that the target tissue is not responding as expected, which is indicative of desensitisation where a higher than normal concentration of the hormone is needed to produce the expected response. Down-regulation of the receptor would be evident as a reduced target tissue concentration for the receptor. Enhanced affinity between hormone X and its receptor or increased sensitivity should show a higher than normal response of the target tissue to the infusion. Hydrophilic hormones are not bound to plasma-proteins as they are soluble in the plasma, so this is not relevant for this hormone.
The correct answer is: Desensitisation to hormone X by the target tissue
32
The correct answer is: Hydrophobic interactions
33
The correct answer is: Long-chain fatty acids
34
The correct answer is: A duty to use information given by a patient only for the purpose for which it was given
35
The correct answer is: No, social determinants are the same for everyone but some groups have more determinants impacting on them at any one time than others
36
The correct answer is:
1. This is a passive transport system that can be saturated at high substrate concentrations → Carrier-mediated transport,
2. This requires a solute concentration gradient to drive water movement across the plasma membrane → Osmosis,
3. This allows particles and large extracellular molecules to be brought into the cell → Endocytosis
37
a) Enzymes do not alter the equilibrium of biological reactions, they lower the activation energy to increase the rate of reaction
b) A catalyst does not cause any reaction to take place that would not occur by itself (i.e. in the absence of an enzyme) given enough time.
c) Correct answer
d) Enzymes are highly specific biological catalysts, so they facilitate one reaction only or a few very closely related reactions. Often these are forward and reverse reactions of the one equilibrium reaction.
e) Enzymes provide amino acid sidechains in their active site which bind the substrate and allow for optimal conformations of molecules for the reaction, but they are unchanged after the reaction has taken place (i.e. these amino acids do not become part of the product)
The correct answer is: decrease the activation energy of the reaction and increase the reaction rate.
38
The lipid bilayer of the cell membrane is hydrophobic, so membrane-spanning proteins are folded so that their hydrophobic amino acids are arranged on the outside of the molecule, and the more hydrophilic amino acids are in the interior of the protein. This is especially seen in membrane channels where the hydrophilic interior is conducive to the passage of ions through the membrane.
The correct answer is: A hydrophobic amino acid
39
The correct answer is: 40%
40
The correct answer is: New South Wales
41
The correct answer is: 50%
42
The correct answer is: 20%
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The correct answer is: 50%
44
The correct answer is: Child and maternal health
45
The correct answer is: Smoking
46
The correct answer is: occurs when the membrane potential moves towards zero
47
The correct answer is: K+ is leaving the cell via voltage gated and passive channels
48
The correct answer is:
1. Catalyses the breakdown of ATP and regulates the activity of enzymes. → Cyclic AMP,
2. Initiates a fast cellular response by binding to receptors on the heart cell to stimulate an increase in contraction force via increased cellular Ca2+. → Adrenaline,
3. Initiates a slow cellular response involving the induction of protein synthesis. → Cortisol
49
1. While the Na+/ K+ ATPase is responsible for setting up the transmembrane ion difference essential for establishing a membrane potential, it uses energy in the form of ATP. The resting cell is permeable to only K+ because only the K+ channels are open.
2. Membrane potential is raised by a local voltage change, opening Na+ channels which rapidly enter down both concentration and electrical gradient to initiate the action potential.
3. Nerve conduction is mediated by Na+ and K+ channel opening and closing until the action potential reaches the nerve terminal. Located only in the nerve terminals, Ca2+ channels are opened by depolarisation of the membrane, allowing Ca2+ entry which stimulates transmitter vesicles to merge with the inner membrane and release their contents into the synapse.
The correct answer is: 1. What is the main contributor to ion movement establishing the resting membrane potential of a nerve or other excitable cell that does not require energy? → K+ channel, 2. A change in membrane potential to raise it above threshold for initiating an action potential activates which contributor to ion movement? → Na+ Channel, 3. An action potential conducted to a nerve terminal will stimulate transmitter release triggered by activation of which main contributor to ion movement? → Ca2+ channel
50
An increase in plasma glucose level following nutrient intake stimulates an increase in plasma insulin levels. Plasma glucagon levels remain fairly steady over a 24 hour period. The ratio of insulin to glucagon changes over a 24 hour period, stimulated by changes in plasma glucose levels.
The correct answer is: Increases in plasma insulin levels are triggered by increases in plasma glucose
51
BMR is increased with increased amount of lean muscle mass as this tissue type has higher oxygen consumption. Females generally have a lower BMR than males, and BMR increases after physical activity and is lowered with increased amount of adipose tissue relative to lean muscle mass, as adipose tissue has very little metabolic activity. Fever increases BMR.
The correct answer is: Is higher in people with more lean muscle mass
52
BMR increases with amount of lean muscle mass as this tissue type has higher oxygen consumption. N.B. Fever increases BMR; however, other effects of fever such as lethargy reduce the body’s energy expenditure in an effort to compensate overall energy expenditure whilst the BMR is raised.
The correct answer is: Increases with amount of lean muscle mass
53
The correct answer is: A structured body of rules, principles and values used to justify or criticise decisions or acts by doctors
54
The correct answer is:
1. An 18 year old male has just opened his letter box and found a letter from his university inside. As he opens the envelope his heart rate rapidly increases as he remembers his application to medical school. Even after opening the envelope and realising he had been offered a place his symptoms persist. → ß1 adrenoreceptors,
2. A 32 year old woman is giving a speak in public for the first time. Before she starts she notices that her hands are clammy. → α adrenoreceptors,
3. A 56 year old woman who suffers from urinary incontinence is being treated with a drug that stops her bladder from contracting. → Muscarinic receptors
55
The correct answer is:
1. She lives at home alone but has help from her 2 supportive daughters who live nearby → Social history,
2. Last year she was prescribed triprim for a week by her doctor and developed a rash → Allergy/adverse reactions history,
3. Had an angiogram 10 months ago which demonstrated a blockage, and a stent was put in → Past medical history,
4. She has had upper abdominal pain on and off for 6 months now, but has gotten much worse in the last 2 weeks → History of Presenting symptoms,
5. Smokes a packet of cigarettes a day, and has done for 55 years → Social history
56
The WHO definition of health is “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity”. Answer A is the only one which includes all important aspects of the definition, including physical, mental and social well-being.
The correct answers are: A state of complete physical and mental well-being, A state of complete physical, mental and social well-being
57
The correct answer is: Pleiotropy
58
Down syndrome is caused by a chromosomal defect and thus will always be present at birth.
The correct answer is: Down syndrome
59
The correct answer is: Hypotonic with respect to the cells
60
All neoplasms, both benign and malignant, show abnormal nuclei. They also have genetic mutations that confer the neoplastic phenotype, which includes abnormal responses to growth factors. Only malignant neoplasms can invade adjacent tissues or spread to distant sites in the body (metastasis).
The correct answer is: Abnormalities of nuclear morphology
61
Enzyme defects usually require both alleles to be abnormal before there is phenotypic expression of disease. This is because they act catalytically and even residual activity is likely to be sufficient to fulfil the function.
The correct answer is: Enzymes
62
Trisomy is a numerical chromosome disorder in which there are 3 copies of the one chromosome. Polyploidies are those disorders in which there are multiple copies of all the chromosomes, such as triploidy (3 copies) and tetraploidy (4 copies). These conditions are incompatible with life. Mosaicism refers to the presence in one tissue type of cells with different genetic compositions despite being derived from the same cell (usually as a result of a mutation).
The correct answer is: Trisomy
63
In autosomal recessive conditions, 2 copies of the mutant or disease gene are required for an individual to be affected. If the parents of that individual are related they have an increased of carrying the mutant allele at the same locus as they could have inherited the mutation from a common ancestor.
The correct answer is: Autosomal recessive
64
The correct answer is: Post-replicative mismatch repair
65
All characteristics listed can be found in any neoplasm (benign and malignant), but invasion of adjacent tissue (D) is specific for malignancy
The correct answer is: Invasion of adjacent tissues
66
This is an important part of mRNA translation and occurs on the ribosomes. All other processes are either transcription or individual steps of RNA maturation, which all occur in the nucleus.
The correct answer is: Elongation of polypeptide chains
67
1. From chondro = cartilage and –oma = benign tumour.
2. From osteo = bone and sarcoma = malignant connective tissue/mesenchymal tumour.
3. A hamartoma is a developmental abnormality composed of non-neoplastic tissue.
The correct answer is: 1. A benign tumour of cartilage. → Chondroma, 2. A malignant tumour of bone. → Osteosarcoma, 3. A lesion that is not neoplastic. → Hamartoma
68
We can assume the father does not have the affected X chromosome, because he doesn’t show the phenotype. Because the mother is a carrier, she must have a “normal” X chromosome (X) and an affected X chromosome (X*). The options for this couple’s offspring are XX, XY, X*X, X*Y. There is a 50% chance a son will show the phenotype and a 50% chance a daughter will be a carrier, but 0% chance that she will show the phenotype as she would need both X’s to be affected (X*X*) for this.
The correct answer is: 0% for a girl, 50% for a boy
69
The correct answer is: Metastasis of the tumour
70
The correct answer is: Remind him that you are a medical student and that you will pass the information on to the doctor
71
Trisomy 21 is most commonly the result of non-disjunction in meiosis 2, occurring during the formation of the female gametes. Some examples of Trisomy 21 are the result of mosaicism (non-disjunction in mitosis) but these are less common and are often of lesser disease severity.
The correct answer is: Non-disjunction in meiosis
72
1. Neutrophils are the “acute inflammatory cells"
2. The morphology of the nuclei suggests neoplasia. The high proliferation fraction is consistent with rapidly multiplying neoplastic cells. Further studies showed the lesion to be a high-grade lymphoma.
The correct answer is:
1. A pathologist receives a biopsy from a red area of skin. Under the microscope she observes large numbers of neutrophils and dilated capillaries. No lymphocytes, plasma cells or eosinophils are seen. → Acute inflammation,
2. A 56 year old female presents with a swelling of the lymph nodes in the neck. A biopsy of one of these nodes shows its normal architecture to have been replaced by a population of cells with large, darkly staining (hyperchromatic), irregular nuclei. Immunohistochemistry demonstrates that about 90% of the cells are in the cell cycle. → Neoplasia
73
Hypertension is affected by the actions of several different genes and also environmental factors such as obesity, salt intake, alcohol consumption, and stress. Down syndrome is an abnormality of chromosome number; Marfan syndrome is an autosomal dominant disorder (single gene defect); phenylketonuria is an autosomal recessive disorder (single gene defect); Prader-Willi syndrome is a single-gene defect with maternal imprinting.
The correct answer is: Hypertension
74
The key event during Telophase is re-enveloping of: separated, haploid sets of chromosomes (in the case of Meiosis I) or separated chromatids (in the case of Meiosis I or Mitosis) that have migrated to opposite ends of the cell. Re-enveloping involves formation of a new nuclear membrane around each set in preparation for Cytokinesis and splitting of the cell into two daughter cells. Remember that Meiosis I HALVES the chromosome number, so during Metaphase of Meiosis I, homologous pairs line up and then separate (with sister chromatids; these will then separate in Meiosis II) such that a haploid set of each migrates to opposite ends of the cell. During Telophase in Meiosis I there is one of each homologous pair of chromosomes (haploid set) still with sister chromatids at each end of the cell. This means that, until the cell splits, it is still a diploid cell, but the chromosomes are arranged in two haploid groups still with sister chromatids, ready to be split into two haploid daughter cells in subsequent Cytokinesis.
The correct answer is: Diploid sperm cells with half their chromosomes at opposite ends of the cell
75
Household deprivation can affect the chances of a child dying before the age of 5 years. Deprivation in early life is also associated with deficits in development across physical, social and emotional, and cognitive and language domains of development. These deficits have lifelong effects on life chances and subsequent health.
The correct answer is: In general, household deprivation can affect the chances of a child dying before the age of 5 years
76
People with poor health literacy skills are less likely to be able to “obtain, process and understand basic health information and services needed to make appropriate health decisions”
The correct answer is: A diabetic person with poor health literacy skills is less likely to understand their glucometer blood sugar readings
77
The correct answer is: Diabetes
78
Review histology of cancer progression in “Hallmarks of Cancer” lecture
The correct answer is: Hyperlastic cells
79
Review histology of cancer progression in “Hallmarks of Cancer” lecture
The correct answer is: Hyperlastic cells
80
The other answers are key factor in uncontrolled growth and metastasis rather than angiogenesis
The correct answer is: Epithelial to mesenchymal transition
81
Image X shows a normal heart. Image Y shows a heart from a patient with longstanding hypertension. Each has been sectioned to demonstrate the left ventricle. A pathologist examines a section from heart Y under the microscope. Which of the following is most likely to be observed?
This is a classic case of hypertrophy, associated with increased cell size.
The correct answer is: Increased size of myocardial cells
82
This is atrophy due to loss of innervation – remember the GOAL on disorders of cell growth.
The correct answer is: Atrophy of the leg muscles;
83
The heart will become infarcted due to the lack of blood supply. Dead heart muscle typically exhibits coagulative necrosis.
The correct answer is: Coagulative necrosis
84
Hypertension is affected by the actions of several different genes. Down syndrome is a chromosomal defect; Marfan is autosomal dominant; phenylketonuria is autosomal recessive; Prader-Willi is a single-gene defect with maternal imprinting.
The correct answer is: Hypertension
85
Following the formation of tetrads between homologous chromosome pairs, crossing over occurs, during which homologous regions of the chromosomes are exchanged between chromatids (the “arms” of the chromosome). This exchange of genes means that the chances of 2 gametes resulting from mitosis having the same genetic composition is 1 in 8 million.
The correct answer is: Crossing over of homologous chromosomes
86
Stratified squamous epithelia are found in areas of the body subject to attrition and keratinized stratified squamous epithelium covers dry surfaces such as the skin. The upper-most (superficial) cells die and become anuclear (without nuclei) but high in keratin. Keratin is a protein present in our hair and fingernails which provides a protective barrier from the external environment.
The correct answer is: Keratinized stratified squamous epithelium
87
A & E are typical processes which occur in apoptosis.
B – Ligand binding may occur in apoptosis (the Fas ligand is an example)
C – Correct answer; lysis of the cell membrane occurs in necrosis, but not in apoptosis.
D - Phagocytosis is the process at the end of apoptosis, by which the cell remnants are eliminated.
The correct answer is: Lysis of the cell membrane with inflammation
88
Caseation is characteristic of tuberculosis.
The correct answer is: Tuberculosis
89
Lack of ATP causes failure of ion pumps and consequent increase in oncontic pressure.
A) Activation of caspases causes apoptosis;
B) the intracellular calcium increases (not decreases) in ischaemic injury;
C) destruction of plasma membranes would cause cell lysis;
D) diapedesis of red blood cells is irrelevant here.
E) (Correct Answer): In ischaemia, reduced oxygen supply inhibits mitochondrial ATP production. Lack of ATP then causes failure of ion pumps and consequently an increase in oncontic pressure resulting in cell swelling.
The correct answer is: Failure of ion pumps
90
The affected male would be genotype Aa, for example, and his partner aa. When you construct a Punnett square you will find that half the offspring are Aa (affected heterozygotes like their father) and the other half are aa (unaffected homozygotes or normal like their mother).
The correct answer is: 50%
91
A. Allosteric activators are additional activators of enzymes, they are not required for their catalytical activity.
B. A ‘prosthetic group’ is covalently bound to the enzyme protein (like haem in haemoglobin)
C. Metal ions may participate in the catalysis of certain enzymes, but they are not coenzymes
D. Correct answer.
E. Regulatory subunits of enzymes are usually proteins themselves, which do not take part in the catalytic action of the enzyme.
The correct answer is: Non-tightly bound non-protein compounds, which may take part in the reaction catalysed by the enzyme
92
Homologous chromosomes are matching pairs which contain the same genes at the same loci; however they may have identical OR non-identical alleles (forms of the same gene) at any particular locus.
The correct answer is: May have the same or different alleles at a particular locus
93
Using X as normal and x as affected (colour blindness gene), the male is xY and the female is Xx. By constructing a Punnett square, it can be seen that the possibilities for their offspring are Xx, xx, XY, xY. Thus, there is a 50% chance of any offspring being affected (xx affected female and xY affected male, compared with Xx carrier female and XY unaffected male).
The correct answer is: 50%
94
Somatic cells undergo cellular division by the process of mitosis.
The correct answer is: Divide by mitosis
95
The correct answer is: Access to medical care
96
The correct answer is: Life style factors e.g. smoking, exercise, diet and alcohol
97
d) correct answer - Ischaemia is the process resulting in transient blood loss.
a) , c), e) may be consequences of such blood loss.
b) involves a serious infective process.
The correct answer is: Ischaemia
98
a) & b) Civil Liability Act states in the standard of care of professionals that peer professional opinion does not have to be widely accepted
c) Compassion is not a legal obligation
d) To exercise care in providing diagnosis, advice and treatment is a legal requirement
The correct answer is: To seek and respect patient’s consent to treatment
99
Thrush is a cutaneous infection caused by resident microflora so is opportunistic infections
a) Cutaneous mycoses: Affect hair, skin, and nails
b) Opportunistic mycoses: Caused by normal microbiota or environmental fungi
c) Subcutaneous mycoses: Beneath the skin
d) Superficial mycoses: Localized, e.g., hair shafts
e) Systemic mycoses: Deep within body can cause a systemic infection but this is not thrush
The correct answer is: Opportunistic
100
The correct answer is:
1. During a blood meal on the mammalian host, an infected fly injects this pathogenic protozoan into skin tissue. → Trypanasoma brucei gambiense,
2. This organism is responsible for causing the most malaria related deaths worldwide → Plasmodium falciparum,
3. This organism is described as a digestive organ flagellate. → Giardia lamblia
101
The correct answer is: Spleen
102
Bacteria coated with C3b adhere to C3b receptors on professional phagocytic cells (and more likely to be engulfed. The molecular basis for this is that the phagocytic cells have C3b receptors which allow them to bind tightly to C3b coater bacterial cells).
The correct answer is: opsonizes bacteria.
103
Antigen selects the few B-lymphocytes, out of many millions, which have cell surface antibody which best 'fits' the antigen.
The correct answers are: Antigen, Chemotactic factors
104
The correct answer is: Neutrophils
105
Changes in the vasculature begins the inflammation response. Therefore the response to injury begins with hyperaemia or increased blood flow. The increased lymphatic flow, margination and emigration occur after the initial increase in blood flow. Granulation tissue forms last of all during healing.
The correct answer is: Hyperaemia
106
The correct answer is: Bite by a insect that might be contaminated
107
Bacteria are complete cells that contain both DNA and RNA. B – Plasmids consist of DNA C - Prions are proteins D- Ribosomes consist of RNA and proteins E – Viruses contain either RNA or DNA
The correct answer is: Bacteria
108
A. Bacilli – bacteria with cell wall
B. Mycobacteria – bacteria with cell wall, although producing mycolic acid instead of peptidpglycans
C. Mycoplasmas – correct answer; live in host cell and do not produce a cell wall.
D. Spirochaetes – bacteria with cell wall
E. Toxoplasmas – protozoa, not bacteria.
The correct answer is: Mycoplasmas
109
Phagocytes engulf bacteria and produce a burst of reactive oxygen species to kill the bacteria.
The correct answer is: Phagocytes
110
Plasmodium – the causative agent for malaria - belongs to the group of protozoa, not bacteria. All other ones are bacteria.
The correct answer is: Plasmodium
111
Good reflection often involves reference to relevant scientific literature, and consultation with mentors or colleagues. It also involves consideration of both personal strengths and weaknesses. Reflection improves clinical skills, and facilitates high-level integration of knowledge which is a key aspect of professional practice.
The correct answer is: Reflection aims to enhance consideration of the larger context, the meaning, and the implications of experiences.
112
As this is a booster vaccination she has already been vaccinated previously. In this instance the memory B-lymphocytes that resulted from the prior exposure to the antigen may recognise the antigen given in the booster vaccination and may initiate an inflammatory reaction. The redness and heat occurs due to increased vascular permeability and the tenderness occurs due to release of inflammatory mediators that activate sensory nerve endings.
The correct answer is: Memory B lymphocytes
113
The vaccination has initiated a local inflammatory reaction. The first part of this reaction is relaxation of the pre-capillary sphincters leading to increased blood flow in the area. This increased blood flow is associated with heat and redness.
The correct answer is: Dilation of blood vessels in the area
114
a) factitious disorder (Munchhausen syndrome)
b) hypochondriasis
c) malingering
d) correct answer
e) conversion disorder.
These mental disorders are known as somatoform disorders and share the appearance of a general medical condition as suggested by one or more physical symptoms.
The correct answer is: Recurring, multiple, clinically significant complaints about pain, gastrointestinal, sexual and pseudoneurological symptoms, for which no medical cause can be found
115
Seasonal hay fever is an allergic reaction that occurs following activation of mast cells leading to release of histamine.
The correct answer is: Histamine
116
C5a is chemotactic for white blood cells, such as neutrophils.
The correct answer is: Complement factor C5a
117
This wound swab contained elements of normal skin flora. That does not necessarily mean that the wound is not infected (this is a clinical call), but might also mean that the sampling was not appropriate or that the patient has been on antibiotics, which could mask the actual pathogen (usually, but not always, Staphylococcus aureus or Streptococci). It is not useful to identify all the pathogens at species level or perform antibiotic susceptibility test for them. Staphylococcus epidermidis is usually a member of the commensal flora.
The correct answer is: This result is not useful, as it just reflects the skin flora from around the wound. If there are indications of inflammation, it is best to discuss the appropriate approach with the Clinical Microbiologist.
118
Smooth muscle utilise GPCR and 2nd messenger signalling to instigate muscle contraction unlike striated and cardiac muscle.
The correct answer is: GPCR receptors.
119
E.g., Pyrimidine analogs include 5-fluorouracil and methotrexate result in inhibition of DNA but not RNA or protein synthesis
The correct answer is: target Enzymes involved in DNA synthesis.
120
Varicella zoster virus can cause chickenpox with associated symptoms (lytic) and also may persist latently in host ganglia cells; non-replicating to be activated at a later stage as shingles.
The correct answer is: a latent and acute lytic infection.
121
Agonists activate drug receptors
Alkylating agents form a reactive ion that attaches to DNA and forms cross linkage
Aminoglycosides inhibit enzymes involved in bacterial protein synthesis
b-lactams (penicillin & cephalosporins) block enzymatic transpeptidase and carboxypeptidase activities
Fluorquinolones interfere with supercoiling of DNA by inhibiting the enzyme topoisomerase II (gyrase)
The correct answer is: b-lactams
122
The correct answer is: The way the drug is distributed in different body compartments
123
The correct answer is: Inhibition of angiogenesis
124
The correct answer is: The effect of the body on the drug
125
The immune system cells that are professional phagocytes are the neutrophils and macrophages.
The correct answer is: Neutrophils
126
The correct answer is: Frontal cortex
127
The cardinal signs of inflammation are heat, redness, pain and swelling
The correct answer is: Atrophy
128
Professional behaviour considered as part of a global judgment of professional behaviour: Professional and personal boundaries – Ability to establish, build and maintain professional therapeutic partnerships with the patient, their family, friends and carers, while maintaining appropriate professional boundaries within those partnerships.
The correct answer is: Patients and their family, carers and friends
129
Microvilli are non-motile projections of the cytoplasm on the apical (top) surface of the cell. They are composed of microfilaments (actin) and their primary function to increase the cell’s surface area. As such, they are commonly found on absorptive surfaces such as in the GI tract and renal tubules.
The correct answers are: In cells that are actively engaged in absorption, On the inside of cell membranes
130
This is an immediate reaction that may lead e.g. to muscle contraction or immediate hormone secretion.
a) is a relatively fast reaction, but it takes time for the metabolic effect to take place.
b) correct answer
c) & e) are part of the gene expression programme, which as a whole is a rather slow adaptation process.
d) Inhibition of DNA synthesis is aimed at growth inhibition (of parasites or cancer cells), which also takes longer to establish a health beneficial effect.
The correct answer is: Ca++ influx into the cytosol
131
The way the body reacts to the drug is pharmacodynamics. The way the body handles the drug is pharmacokinetics. This includes absorption, distribution metabolism and elimination.
The correct answers are: The effect of saliva on drug absorption, The effect of the drug on the body
132
The correct answer is: They always cause disease
133
Carbohydrates are the main source of glucose in the body; a meal high in carbohydrate content will increase plasma glucose the most.
The correct answer is: After intake of carbohydrates
134
BMR is increased with physical activity and amount of lean muscle mass as this tissue type has higher oxygen consumption. None of the other factors will increase the BMR. Note that a reduction in body weight via dieting but in the absence of increased physical activity, (particularly in someone who is not overweight), may not affect their ratio of body fat to muscle and will therefore not necessarily help to increase their BMR.
The correct answer is: Increase their physical activity
135
The correct answer is: A duty to exercise the degree of care that reasonable doctors would exercise in the same circumstances
136
Lysosomes are important waste-disposal organelles that contain enzymes known as acid hydrolases. Cells use these to degrade foreign bodies (such as bacteria) and to perform autophagy, the process by which cells break down worn out organelles and cellular structures for re-use.
The correct answer is: Digest cellular wastes and bacteria
137
Neutrophils are the characteristic cell of an acute inflammatory reaction and so would be present in at the site of a peptic ulcer.
The correct answer is: Neutrophils
138
Both lungs can be seen, so that image must be in either a coronal (frontal) or transverse (horizontal) plane. A sagittal or midsagittal (same as median) plane does not bisect both lungs, so only one lung would be seen on a single image in this plane. Ipsilateral means the same side, so the radiologist is still referring to the right side, but this is relevant to both a coronal and a transverse image. Using the description “superior” means that the viewer can distinguish between superior and inferior, which means it must be a coronal plane image.
The correct answer is: Coronal
139
The small intestine is intraperitoneal (invested in visceral peritoneum). The brain is in the cranial cavity, the heart in the pericardial cavity, separated from the abdominal cavity by the diaphragm, and the bladder and rectum are outside the limits of the peritoneal cavity.
The correct answer is: Small intestine
140
The correct answer is: No, there is a shortage of all health professionals in these areas.
141
Connection to land is the single most important issue from which all cultural, and therefore health, degradation stems.
The correct answer is: Negatively, because colonists took possession of land, thereby disrupting culture(s).
142
Whilst basal metabolic rate, usual intake of protein, carbohydrates and fat, and lean muscle mass will contribute to a person’s usual metabolic rate and energy expenditure, “excessive, unplanned weight loss” would be more likely attributable to something pathological, such as a change in catabolic hormones, such as thyroid hormones, or catecholamines. Her body mass index and waist circumference might be a good measure for comparison, but will not help with a differential diagnosis.
The correct answer is: Her plasma levels of catabolic hormones
143
1. This is a description of Barrett oesophagus.
2. The softened brain is infarcted; dead brain tissue typically shows colliquative necrosis.
3. The biopsy shows a pattern of chronic inflammation. This patient could have chronic inflammatory bowel disease.
The correct answer is: 1. A doctor performing an endoscopy finds the lower end of the oesophagus to be lined by salmon-pink mucosa. A biopsy of this area shows glandular epithelium of intestinal type. → Metaplasia, 2. A 71 year old male develops the symptoms and signs of a stroke, and dies a week later. An autopsy is performed and the pathologist finds an area of softening in the brain. → Colliquative necrosis, 3. A patient with chronic diarrhoea has a biopsy of the rectal mucosa which shows infiltration of the lamina propria by large numbers of lymphocytes and plasma cells. There are no granulomas. → Chronic inflammation
144
Lysosomes contain enzymes known as “acid hydrolases”. This means they are active at the acidic pH (~ 5) of the lysosome but not at neutral or alkaline pH values.
The correct answer is: Acidic pH
145
The correct answer is: 1. This organelle modifies proteins and packages them into secretory vesicles for export from the cell → Golgi apparatus, 2. Site of synthesis of cholesterol, phospholipids for membranes and other hydrophobic products of lipid metabolism → Smooth endoplasmic reticulum, 3. A ribonucleoprotein particle that uses RNA instead of protein for its catalytic activity. → Ribosome
146
When core body temperature decreases, heat needs to be conserved, so blood flow to the more superficial dermal papillary capillaries is reduced via dermal arteriole vasoconstriction. This diverts blood through the dermal arteriovenous anastomoses, so that less heat is lost at the skin surface and thus conserved for the body’s internal tissues. Oxygen deficiency in the blood is characterised by a blue skin colour. Stimulation of piloerector muscles to contract will result in the appearance of goose bumps, which is also a physiological response to attempt to prevent loss of body temperature.
The correct answer is: Constriction of dermal arterioles
147
Since the boy has suffered only sensory effects, there is damage to a structure containing only sensory nerve axons, and no damage to structures associated with muscle function. The dorsal root contains sensory axons that are returning to the central nervous system, while the ventral root contains motor axons that are travelling from the CNS to the periphery. The grey matter of the spinal cord contains neuron cell bodies, including motor neurons, and the white matter contains axons: both sensory and motor, so damage to these areas would result in more than just sensory loss. The brainstem is involved in autonomic functions and damage here would result in much greater and widespread effects, possibly effects on consciousness, breathing, etc.
The correct answer is: Dorsal root of the spinal cord
148
a) Although normal colonic flora consists >90% by Bacteroides group anaerobes, normal oral anaerobic flora consists mainly of Prevotella spp., Fusobacterium spp., Actinomyces spp.
b) Opportunistic pathogens are less virulent, that’s why they prevail when the immune defence is impaired.
c) Although opportunistic infections of this kind are found almost exclusively in immunosuppressed patients, the latter are also prone (even more susceptible than people with normal immune function) to infections by common, virulent bacterial pathogens.
d) and e) are equally correct.
The correct answer is: Patients with impaired T-cell immunity do not get infections by common bacteria, e.g. S. aureus or Enterobacteriaceae, but only form opportunistic pathogens, like Pneumocystis jirovecki or CMV.
149
a) Archaea are a completely different group of bacteria. They tend to live under extreme conditions and are not human parasites.
b) Bacterial endospores are resistant to antibiotics.
c) Gram-negative bacteria are less sensitive than gram-positive, since their cell walls have a smaller component of peptidoglycan.
d) These have cell walls with the a large component of peptidoglycan.
e) Mycoplasmas do not have cell walls that contain peptidoglycan; in fact they live intracellularly and do not have a proper cell wall at all.
The correct answer is: Gram-positive bacteria
150
a) Many bacteria are, so this does not determine medical importance.
b) This contributes to medical importance, but many bacteria have multiple virulence factors, so this is not the most correct answer.
c) This does not determine medical importance.
d) S. aureus is cause of a range of infections, but enteric infections are typically not caused by S. aureus.
e) It can be resistant to antibiotic treatment.
The correct answer is: It is relatively common and can be resistant to antibiotic treatment.
151
a) Toxoplasma gondii is not a flagellate.
b) Lyme disease is caused by a bacteria and Toxoplasma gondii is not a flagellate.
c) It is a protozoan, not a bacterium.
d) Toxoplasma gondii is not an amoeba.
e) correct answer
The correct answer is: Ingested by the host through faecal oocysts in contaminated food or water
152
The correct answer is:
1. Can cause a wide variety of endemic human diseases. → Commensal resident microflora,
2. Biofilm formation is an example of this. → Surface factor,
3. The Shiga toxin released by the bacterium Shigella dysenteriae is an example of this. → Exotoxin
153
The correct answer is: Streptococcus pyogenes
