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Question 1
Incorrect
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Which one of the following is true about bone marrow?
Your Answer: All of options are true
Correct Answer: At birth the bone marrow is entirely red marrow and is converted to yellow marrow with age
Explanation:The two types of bone marrow are red marrow, which consists mainly of hematopoietic tissue, and yellow marrow, which is mainly made up of fat cells. Red blood cells, platelets, and most white blood cells arise in red marrow. Both types of bone marrow contain numerous blood vessels and capillaries. At birth, all bone marrow is red. With age, more and more of it is converted to the yellow type; only around half of adult bone marrow is red.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 2
Correct
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The enzyme that catalyses the final step in glycogen synthesis is:
Your Answer: Glycogen synthase
Explanation:Glycogen synthase is a key enzyme in glycogenesis, the conversion of glucose into glycogen. This enzyme combines excess glucose residues one by one into a polymeric chain for storage as glycogen.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 3
Correct
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During which phase of meiosis does exchange of genetic material occur accounting for genetic diversity between individuals:
Your Answer: Prophase 1
Explanation:Prophase 1 has been divided into five different stages ( laptotene, zygotene, pachytene, diplotene ans diakinesis). In prophase 1 chromosomes are going to condense to become visible, each chromosome will contain two chromatids that are joined at the centromere. the nucleolus and nuclear envelope are going to disintegrate. the homologous chromosomes will form tetrad and crossing over will occur between the chromosomes (random exchange of genes), the point of exchange is known as the chiasmata, this increases genetic diversity.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 4
Correct
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Question 5
Correct
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What is the mechanism of action of sildenafil citrate?
Your Answer: Inhibition of phosphodiesterase V
Explanation:Sildenafil citrate (Viagra) is the first oral drug to be widely approved for the treatment of erectile dysfunction. It is a potent and selective inhibitor of type-V phosphodiesterase, the primary form of the enzyme found in human penile erectile tissue, thereby preventing the breakdown of cyclic guanosine monophosphate (cGMP), the intracellular second messenger of nitric oxide.Uses:It is used for the treatment of erectile dysfunction, idiopathic pulmonary hypertension, premature ejaculation, high altitude illness, penile rehabilitation after radical prostatectomy, angina pectoris, and lower urinary tract symptoms.Adverse effects:Mild headache, flushing, dyspepsia, cyanopsia, back pain, and myalgias – due to a high concentration of PDE11 enzyme in skeletal muscle, which shows significant cross-reactivity with the use of tadalafil.It can also cause hypotension, dizziness, and rhinitis.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 6
Incorrect
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Which of the following statements with regards to regulation of pulmonary blood flow is correct:
Your Answer: Increased CO2 causes a decrease in pH causing vasodilation
Correct Answer: Decreased blood flow to a region causes constriction of bronchi that area
Explanation:Oxygen deficiency or hypoxia has a direct effect on pulmonary vessels and results in vasoconstriction. Increased carbon dioxide levels causes pH levels to fall and results in pulmonary vasoconstriction. Decreased blood flow to a pulmonary region causes bronchoconstriction in that area to allow for flow of blood to an area where ventilation is high. Exercise increases demand of oxygen and causes increased pulmonary artery pressure.
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 7
Incorrect
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A patient who has mild benign prostatic hyperplasia has been advised to take finasteride.The mechanism of action of this drug involves inhibition of the production of which of the following androgens?
Your Answer: Androsterone
Correct Answer: Dihydrotestosterone
Explanation:Finasteride inhibits the formation of dihydrotestosterone.Finasteride is a 5α-reductase inhibitor and thus, inhibits the conversion of testosterone to dihydrotestosterone (DHT). DHT is much more active than testosterone and binds more avidly to cytoplasmic receptors. DHT stimulates prostate growth and may be responsible for benign prostatic hyperplasia in the elderly. Thus, finasteride can cause a reduction in prostatic volume and help in managing a patient with benign prostatic hyperplasia.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 8
Correct
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In the absence of insulin:
Your Answer: Glucose uptake by most of the brain is normal
Explanation:Although it is known that insulin levels affect glucose uptake, oxidation and storage in peripheral tissues, its role in the brain isn’t as clear. However, studies have shown that bulk brain glucose uptake isn’t affected by insulin. Glucose transport into the neurons is GLUT3 dependent, and its transport into glia and brain endothelial cells rely on GLUT1. Insulin isn’t necessary for GLUT1 or GLUT3, which explains why brain glucose uptake isn’t affected by insulin levels.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 9
Correct
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What is the average life span of neutrophils?
Your Answer: 24 hours
Explanation:The average lifespan of inactivated human neutrophils in the circulation has been reported by different approaches to be between 5 and 90 hours.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 10
Incorrect
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Cholinergic nerves from the vagus innervate the SA and AV nodes via which receptor in the heart?
Your Answer: M1 receptor
Correct Answer: M2 receptor
Explanation:M2 receptor is found in the heart. M3 and M4 are associated with smooth muscle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 11
Correct
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What is the primary cause of ketoacidosis in Type 1 diabetes?
Your Answer: Lipolysis
Explanation:in type 1 diabetics the lack of insulin in the bloodstream prevents glucose absorption, thereby inhibiting the production of oxaloacetate (a crucial precursor to the β-oxidation of fatty acids) through reduced levels of pyruvate (a by-product of glycolysis), and can cause unchecked ketone body production (through fatty acid metabolism or lipolysis) potentially leading to dangerous glucose and ketone levels in the blood.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 12
Incorrect
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Which structure forms the major part of the sternocostal surface of the heart?
Your Answer: Left atrium
Correct Answer: Right ventricle
Explanation:The anterior (sternocostal) surface is formed mainly by the right ventricle.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 13
Incorrect
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Which one of the following is necessary to activate plasminogen to plasmin?
Your Answer: Α2-microglobulin
Correct Answer: tPA
Explanation:In circulation, plasminogen adopts a closed, activation resistant conformation. Upon binding to clots, or to the cell surface, plasminogen adopts an open form that can be converted into active plasmin by a variety of enzymes, including tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), kallikrein, and factor XII (Hageman factor).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 14
Incorrect
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In the jugular venous pressure wave…
Your Answer: ‘v’ wave coincide with rapid ventricular filling phase
Correct Answer: Consists of 3 peaks and 2 troughs
Explanation:The jugular venous pressure (JVP, sometimes referred to as jugular venous pulse) is the indirectly observed pressure over the venous system via visualization of the internal jugular vein. It can be useful in the differentiation of different forms of heart and lung disease. Classically three upward deflections (peaks) and two downward deflections (troughs) have been described:The upward deflections are the a (atrial contraction), c (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systole) and v = venous filling.The downward deflections of the wave are the x (the atrium relaxes and the tricuspid valve moves downward) and the y descent (filling of ventricle after tricuspid opening).
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 15
Incorrect
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The formation of superoxide is catalysed by which enzyme?
Your Answer: Oxide reductase
Correct Answer: NADPH oxidase
Explanation:Superoxide is biologically toxic and is deployed by the immune system to kill invading microorganisms. In phagocytes, superoxide is produced in large quantities by the enzyme NADPH oxidase for use in oxygen-dependent killing mechanisms of invading pathogens.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 16
Incorrect
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Which of the following suggests the presence of mitral regurgitation as well as mitral stenosis?
Your Answer: Atrial fibrillation
Correct Answer: Displaced apex beat
Explanation:Mitral stenosis on its own does not lead to left ventricular dilatation and hence a displaced apex beat. Thus a displaced apex beat is suggestive of mixed mitral disease. The other options occur in mitral stenosis.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 17
Correct
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Question 18
Incorrect
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Which of the following treatments would you advise for a young, 21 year old student who has ankylosing spondylitis and complains of worsening back pain and morning stiffness?
Your Answer: Paracetamol
Correct Answer: Oral NSAIDs
Explanation:NSAIDs are considered as the first line of treatment for managing pain and stiffness associated with ankylosing spondylitis. Other useful medications include TNF-alpha inhibitors. Other drugs like paracetamol, colchicine, and steroids are not routinely used. Bilateral total hip replacement might be indicated in advanced disease contrary to complicated spinal surgery.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 19
Incorrect
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In meiosis, the period of prophase 1 involves:
Your Answer: The production of two identical daughter cells
Correct Answer: Replicated DNA condensing to form visible chromosomes
Explanation:Prophase 1 has been divided into five different stages (laptotene, zygotene, pachytene, diplotene and diakinesis). In prophase 1, chromosomes are going to condense to become visible, each chromosome will contain two chromatids that are joined at the centromere.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 20
Correct
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Which one of the following skin disorders is least commonly associated with hypothyroidism?
Your Answer: Pretibial myxoedema
Explanation:Pretibial myxoedema is an infiltrative dermopathy, resulting as a rare complication of Graves’ disease (hyperthyroidism) and very occasionally occurs in non-thyrotoxic Graves’ disease and Hashimoto’s thyroiditis.
Hypothyroidism typically presents with symptoms such as dry skin, brittle hair, and thinning of the outer third of the eyebrows. While skin conditions like dryness and hair changes are common in hypothyroidism due to reduced metabolic activity, acne is also not typically associated with it.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 21
Incorrect
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Which of the following statements regarding psoriasis is incorrect?
Your Answer: Phototherapy is a form of treatment
Correct Answer: Mediated by type 2 helper T cells
Explanation:Psoriasis is a long-lasting autoimmune disease which is characterized by patches of abnormal skin. These skin patches are typically red, itchy, and scaly commonly on the extensor surfaces. Psoriasis is associated with an increased risk of psoriatic arthritis, lymphomas, cardiovascular disease, Crohn’s disease, and depression. Psoriatic arthritis affects up to 30% of individuals with psoriasis. Psoriasis is mediated by type 1 helper T cells which are involved in the cell mediated response, rather than type 2 helper T cells
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 22
Incorrect
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Chief cells secrete:
Your Answer: HCL and pepsinogen
Correct Answer: Pepsinogen and gastric lipase
Explanation:A gastric chief cell (or peptic cell, or gastric zymogenic cell) is a type of cell in the stomach that releases pepsinogen and gastric lipase.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 23
Incorrect
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The energy needed for glycogen synthesis comes from which compound?
Your Answer: NADPH
Correct Answer: UTP
Explanation:Glycogen synthesis is, unlike its breakdown, endergonic—it requires the input of energy. Energy for glycogen synthesis comes from uridine triphosphate (UTP)
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 24
Incorrect
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The ability of the SA node cells to allow ionic flow through channels activated in a hyperpolarized state is known as:
Your Answer: All of the above
Correct Answer: Pace maker potential
Explanation:Rhythmically discharging cells have a membrane potential that, after each impulse, declines to the firing level. Thus this prepotential or Pacemaker potential triggers the next impulse. The inherent leakiness of the sinus nodal fibers to Na+ and Ca2+ causes their self excitation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 25
Incorrect
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The transport of the di- and tri-peptides into enterocytes is by:
Your Answer: H+ dependent peptide transporter 2
Correct Answer: H+ dependent peptide transporter 1
Explanation:Peptides longer that four amino acids are not absorbed. There is abundant absorption of di and tri peptidases in the small intestine. They are absorbed into the epithelial cell of the small intestine via a transporter called Peptide Transporter 1 by co transport with H+ ions.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 26
Incorrect
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What is the main function of vitamin E?
Your Answer: It helps in the formation of red blood cells
Correct Answer: It is an antioxidant
Explanation:Vitamin E has many biological functions, the antioxidant function being the best known. Other functions include enzymatic activities, gene expression, and neurological function(s).
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This question is part of the following fields:
- Haematology
- Medicine
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Question 27
Incorrect
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A 27-year-old male is admitted after drinking engine coolant in an apparent suicide attempt. Lab investigations reveal:
- pH 7.1 (7.36-7.44)
- pO2 15.3 kPa (11.3-12.6)
- pCO2 3.2 kPa (4.7-6.0)
- Standard bicarbonate 2.2 mmol/L (20-28)
- Serum calcium 1.82 mmol/L (2.2-2.6)
Your Answer: Gastric lavage
Correct Answer: Fomepizole infusion
Explanation:The patient’s symptoms and lab results are indicative of ethylene glycol poisoning, commonly found in engine coolant. Ethylene glycol is metabolized to toxic metabolites, including glycolic acid and oxalic acid, which can cause metabolic acidosis (evidenced by the low pH and low bicarbonate levels) and can bind calcium, leading to hypocalcemia.
Fomepizole is an antidote that inhibits alcohol dehydrogenase, the enzyme that converts ethylene glycol into its toxic metabolites. This prevents further formation of the harmful substances, allowing time for the ethylene glycol to be excreted unchanged in the urine.
While haemodialysis is also an important treatment for severe ethylene glycol poisoning, especially in cases of significant acidosis or renal failure, the immediate administration of fomepizole is the most urgent intervention to prevent further toxicity. Haemodialysis can be considered if the patient does not respond adequately to fomepizole or if there are signs of severe toxicity.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 28
Incorrect
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A 55 year old cardiac patient is comfortable at rest but heavy housework results in fatigue, palpitations or dyspnoea. What New York Heart Association class best describes the severity of their disease?
Your Answer: NYHA Class I
Correct Answer: NYHA Class II
Explanation:New York Heart Association functional classification:
Class I: no limitation is experienced in any activities; there are no symptoms from ordinary activities.
Class II: slight, mild limitation of activity; the patient is comfortable at rest or with mild exertion.
Class III: marked limitation of any activity; the patient is comfortable only at rest.
Class IV: any physical activity brings on discomfort and symptoms occur at rest.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 29
Incorrect
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Dietary starch is mainly:
Your Answer: Amylose
Correct Answer: Amylopectin
Explanation:Dietary starch consists of two types of molecules: the linear and helical amylose and the branched amylopectin. Starch generally contains 20 to 25% amylose and 75 to 80% amylopectin by weight but depends in the plant. Glycogen, the glucose store of animals, is a more branched version of amylopectin.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 30
Incorrect
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What is the mechanism of action of carbimazole?
Your Answer:
Correct Answer: Inhibition of the iodination of tyrosine
Explanation:Carbimazole is used to treat hyperthyroidism. Carbimazole is a pro-drug as after absorption it is converted to the active form, methimazole. Methimazole prevents thyroid peroxidase enzyme from coupling and iodinating the tyrosine residues on thyroglobulin, hence reducing the production of the thyroid hormones T3 and T4 (thyroxine).
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This question is part of the following fields:
- Medicine
- Pharmacology
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SESSION STATS - PERFORMANCE PER SPECIALTY
