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Question 1
Incorrect
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A 42-year-old female with type 1 diabetes who has undergone a renal transplant is being reviewed. She is taking azathioprine and tacrolimus for immunosuppression.Which among the following is correct regarding the given immunosuppressive agents?
Your Answer: Azathioprine inhibits pyrimidine synthesis
Correct Answer: Tacrolimus is a calcineurin inhibitor
Explanation:Tacrolimus is a calcineurin inhibitor used as an immunosuppressive agent used for prophylaxis of organ rejection post-transplant.Pharmacology: Calcineurin inhibition leads to reduced T-lymphocyte signal transduction and IL-2 expression. It has a half-life of 12 hours (average).Other off-label indications for the use of tacrolimus include Crohn disease, graft-versus-host disease (GVHD), myasthenia gravis, rheumatoid arthritis.Adverse effects of tacrolimus includes: Cardiovascular: Angina pectoris, cardiac arrhythmias, hypertensionCentral nervous system: Abnormal dreams, headaches, insomnia, tremors.Dermatologic: Acne vulgaris, alopecia, pruritis, rashEndocrine and metabolic: Decreased serum bicarbonate, decreased serum iron, new-onset diabetes mellitus after transplant (NODAT), electrolyte disturbances.Gastrointestinal: Abdominal pain, nausea, vomiting, diarrhoeaGenitourinary: Urinary tract infectionHepatic: Abnormal hepatic function testsNeuromuscular and skeletal: Arthralgia, muscle crampsOphthalmic: Blurred vision, visual disturbanceOtic: Otalgia, otitis media, tinnitusRenal: Acute renal failureOther options:Sirolimus (a macrolide) is an mTOR inhibitor that blocks the response to IL-2 and has a half-life of 12–15 hours. Azathioprine inhibits purine synthesis, an essential step in the proliferation of white cells and has a half-life of around 5 hours.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 2
Incorrect
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On which presynaptic receptor does noradrenalin act to inhibit noradrenalin secretion?
Your Answer: Β1 receptor
Correct Answer: Α2 receptor
Explanation:Adregenic receptors are A1, A2, B1, B2, B3. Out of these, the function of the A2 receptor is inhibition of transmitter release including nor adrenalin and acetylcholine of the autonomic nervous system.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 3
Correct
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The majority of corticospinal tract fibers decussate in the:
Your Answer: Medulla
Explanation:The corticospinal tract is a descending motor path way that begins in the cerebral cortex and decussates in the pyramids of the medulla.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 4
Correct
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The predominant site in the lymph node where B lymphocytes are found is:
Your Answer: Cortex
Explanation:The cortex of the lymph node consists of the lymphoid nodules and sinusoids and posses a germinal centre from which B cells proliferate. The cortex of the lymph node predominately consists of B cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 5
Incorrect
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A 35-year-old female has been recently diagnosed with hypertension. She's sexually active and is not using any birth control other than barrier method. Which among the following antihypertensives is contraindicated in this patient?
Your Answer: Labetalol
Correct Answer: Lisinopril
Explanation:Among the following hypertensives, lisinopril (an ACE inhibitor) is contraindicated in patients who are planning for pregnancy.Per the NICE guidelines, when treating the woman in question, she should be treated as if she were pregnant given the absence of effective contraception. ACE inhibitors such as lisinopril are known teratogens and most be avoided.Drugs contraindicated in pregnancy:AntibioticsTetracyclinesAminoglycosidesSulphonamides and trimethoprimQuinolonesOther drugs:ACE inhibitors, angiotensin II receptor antagonistsStatinsWarfarinSulfonylureasRetinoids (including topical)Cytotoxic agentsThe majority of antiepileptics including valproate, carbamazepine, and phenytoin are known to be potentially harmful.
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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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Free radicals are best defined by which of the following statements.
Your Answer: Atoms or molecules with unpaired counter molecules
Correct Answer: Atoms or molecules with unpaired electrons
Explanation:Free radicals form when one of weak bond between electrons is broken and an uneven number of electrons remain. This means the electron is unpaired, making it chemically reactive and attempt to steal an electron from a neighbouring molecule to stabilize itself.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 7
Correct
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Critical shortening of Telomeres result in:
Your Answer: Activation of p53 and prb and cell crisis
Explanation:Telomeres are repetitive nucleotide sequences at the ends of chromosomes that protect them from deterioration or from fusion with neighboring chromosomes. Each time a cell divides, its telomeres shorten. When they become critically short, they can no longer protect the chromosome ends, triggering a DNA damage response.
This response leads to the activation of tumor suppressor proteins p53 and pRb (retinoblastoma protein). Activated p53 can induce cell cycle arrest, allowing time for DNA repair or triggering apoptosis if the damage is irreparable. Similarly, pRb helps regulate cell cycle progression and can halt the cell cycle to prevent the proliferation of cells with damaged DNA.
As a result, the cell enters a state of crisis, characterized by widespread cell death and genomic instability, which ultimately prevents the propagation of cells with critically shortened telomeres.
Therefore, the correct answer is:
Activation of p53 and pRb and cell crisis
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This question is part of the following fields:
- Genetics
- Medicine
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Question 8
Correct
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The T-tubular system in cardiac muscle is:
Your Answer: Transmits action potential from sarcolemma to the SR to allow for Ca2+ release into the cytoplasm
Explanation:Action potentials are transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ from the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors, which are voltage gated calcium channels.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 9
Correct
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A 50-year-old man is admitted with nausea and excessive drowsiness after taking an antihistamine tablet with grapefruit juice. Which of the following liver enzyme systems is affected by grapefruit juice causing the given side effect?
Your Answer: Cytochrome p450 3A4
Explanation:The cytochrome p450 3A4 enzyme system in the liver is affected by grapefruit juice. Patients taking antihistamines should be advised to avoid drinking grapefruit juice. This is because constituents of grapefruit juice such as naringin and bergamottin inhibit CYP3A4 in the liver, particularly at high doses, leading to decreased drug elimination via hepatic metabolism and can increase potential drug toxicities. Inhibition of this enzyme system leads to reduced metabolism of antihistamines leading to an increased incidence of side effects like excessive drowsiness and nausea as in this patient.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 10
Incorrect
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von Willebrand factor stabilises which clotting factor?
Your Answer: Factor V
Correct Answer: Factor VIII
Explanation:Von Willebrand factor’s primary function is binding to other proteins, in particular factor VIII, and it is important in platelet adhesion to wound sites. It is not an enzyme and, thus, has no catalytic activity. Factor VIII degrades rapidly when not bound to vWF. Factor VIII is released from vWF by the action of thrombin.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 11
Correct
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Question 12
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 13
Correct
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With regard to carbohydrate absorption, which sodium-dependent glucose transporter (SGLT) is responsible for the uptake of dietary glucose from the gut?
Your Answer: SGLT 1
Explanation:SGLT- Sodium-dependent glucose cotransporter or sodium-glucose linked transporter are family of proteins of different types. SGLT1 transporter is found in the intestinal mucosa of the small intestine.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 14
Correct
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The motor speech area (Brocas Area) is:
Your Answer: Brodmann area 44
Explanation:A Brodmann area in the brain is defined by cytoarchitecture, histology and organization of cells:Primary Sensory 3,1,2Primary Motor 4Premotor 6Primary Visual 17Primary Auditory 41Brocas 44
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This question is part of the following fields:
- Medicine
- Neurology
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Question 15
Correct
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The net effect of parathyroid hormone on calcium and phosphate homeostasis is?
Your Answer: Increase in Ca, decrease in phosphate
Explanation:Parathyroid hormone’s main target organs are the kidneys, bone, and intestine. In the kidney, it decreases reabsorption of phosphate and increases calcium reabsorption. It also promotes absorption of calcium from bone. PTH release results in a small drop in serum phosphate concentrations.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 16
Correct
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A 39-year-old accountant with long-standing gastro-oesophageal reflux disease is reviewed in clinic. He has recently switched from ranitidine to omeprazole. What is the main benefit of omeprazole compared to ranitidine?
Your Answer: Irreversible blockade of H+/K+ ATPase
Explanation:Proton pump inhibitors can reduce gastric acid secretion by up to 99%. Acid production resumes following the normal renewal of gastric parietal cells.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 17
Incorrect
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What is the mode of action of bisphosphonates?
Your Answer: Promotes osteoblasts
Correct Answer: Inhibit osteoclasts
Explanation:Bisphosphonates are analogues of pyrophosphate, a molecule which decreases demineralisation in bone. They inhibit osteoclasts by reducing recruitment and promoting apoptosis.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 18
Correct
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What is the protective hexametric sequence at the ends of chromosomes called?
Your Answer: Telomere
Explanation:Telomeres are non coding DNA plus proteins that are found at the end of the linear chromosomes. They maintain the integrity of the chromosomes and prevent their shortening.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 19
Incorrect
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In the absence of insulin:
Your Answer: Intestinal absorption of glucose is increased
Correct 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 20
Incorrect
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90% of erythropoietin necessary for haemopoesis is produced by the kidneys, the remainder is formed in the?
Your Answer: Bone marrow
Correct Answer: Liver
Explanation:Erythropoietin is produced by interstitial fibroblasts in the kidney in close association with peritubular capillary and proximal convoluted tubule. It is also produced in perisinusoidal cells in the liver. While liver production predominates in the fetal and perinatal period, renal production is predominant during adulthood.
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This question is part of the following fields:
- Haematology
- Medicine
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Question 21
Correct
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Cold receptors are likely to be active at the following temperatures except?
Your Answer: 39 °C
Explanation:Cold and Menthol receptor 1 (CMR1) is a protein that in humans is encoded by TRPM8 gene. It is primarily responsible for the detection of temperatures ranging from 8-28 C. It is an ion channel which upon activation causes the influx of Na+ and Ca+ ions into the cell that leads to the depolarization and generation of an action potential.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 22
Correct
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Where would one normally find venous valves?
Your Answer: Saphenous vein
Explanation:The intima of the limb veins is folded at intervals to form venous valves that prevent retrograde flow. There are no valves present in the very small veins, the great veins, or the veins in the brain and viscera.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 23
Correct
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In which area is depolarization initiated?
Your Answer: SA node
Explanation:SA node is the pacemaker of the heart. It determines the rate of contractions. It is the place where depolarization is initiated. It exhibits phase 4 depolarization or automaticity. Electrical impulses then spread to the AV node, purkinje fibers, bundle of his and the ventricular muscles.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 24
Correct
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When one of the two copies of the autosomes has a mutation and the protein produced by the normal form of the gene cannot compensate. The affected individual has an:
Your Answer: Autosomal dominant disorder
Explanation:An autosomal dominant trait will be expressed no matter the consequence. If one chromosome has a mutation the other will not be able to compensate for the mutation hence the protein formed will be mutated and will not function properly.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 25
Correct
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Lipid- lowering drugs like Lovastatin reduce cholesterol synthesis by inhibiting which enzyme?
Your Answer: HMG-CoA reductase
Explanation:Statins, also known as HMG-CoA reductase inhibitors, are a class of lipid-lowering medications. Statins have been found to reduce cardiovascular disease (CVD) and mortality in those who are at high risk.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 26
Correct
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A 28 year old man was rushed to the hospital after experiencing sudden onset chest pain while playing football. He has never felt such pain in the past. However, one of his uncles had a similar sudden discomfort at a young age and he passed away following a heart problem. The following vitals are recorded on examination:BP: 101/74 mmHgRR: 22 breaths/minPR: 87 beats/min Physical examination reveals abnormally long fingers and on asking the man to hold the opposite wrist, the thumb and little finger overlap each other. He is not taking any medication regularly and past medical/surgical history is not significant. He admits to smoking half pack of cigarettes/day for the last 10 years but denies abusing any illicit drugs. Which of the following explanation most likely explains the disease process in this man?
Your Answer: A defect of the glycoprotein structure which usually wraps around elastin
Explanation:Aortic dissection is defined as separation of the layers within the aortic wall. Tears in the intimal layer result in the propagation of dissection (proximally or distally) secondary to blood entering the intima-media space. This can be caused as a result of both congenital or acquired factors like chronic uncontrolled hypertension. This patient shows no sign of hypertension but his physical examination hints towards Marfan Syndrome. Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder affecting the microfibrils and elastin in connective tissue throughout the body. MFS is associated with pathological manifestations in the cardiovascular system (e.g., mitral valve prolapse, aortic aneurysm, and dissection), the musculoskeletal system (e.g., tall stature with disproportionately long extremities, joint hypermobility), and the eyes (e.g., subluxation of the lens of the eye). Decreased collagen production occurs in ageing, hydroxylation defects are present in vitamin C deficiency, copper deficiency affecting lysyl oxidase enzyme occurs in Menke’s disease.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 27
Correct
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Question 28
Incorrect
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During which phase of the cell cycle does transcription of DNA synthesis molecules occur?
Your Answer: G0
Correct Answer: S
Explanation:DNA synthesis occurs in the S phase of the cell cycle. In the G1 phase the cell prepares to divide. In G2 the cellular organelles divide and in the M phase mitosis occur. In the G0 phase the cell becomes quiescent and does not divide further.
Interphase is composed of G1 phase (cell growth), followed by S phase (DNA synthesis), followed by G2 phase (cell growth). At the end of interphase comes the mitotic phase, which is made up of mitosis and cytokinesis and leads to the formation of two daughter cells.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 29
Correct
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An 87-year-old woman had to double up her dosage of morphine 60mg into 120mg twice a day, in addition to another 10mg oral Morphine 6 times a day. What is the best method of management?
Your Answer: Subcutaneous morphine infusion
Explanation:Stable dose of Morphine is essential for chronic cases of pain that are non-malignant in origin. Using the SC route avoids having to intravenously cannulate a patient and allows for a continuous infusion of drugs over a calculated period of time providing constant dosing A significant advantage is that plasma levels of a drug are much more stable, and appropriate symptom control can be achieved without the toxic effects of the peaks and troughs resulting from episodic drug administration.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 30
Correct
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Endotoxin
Your Answer: Composed of Lipid A in liposaccharide in cell wall
Explanation:Lipopolysaccharides (LPS), also known as lipoglycans and endotoxins, are large molecules consisting of a lipid (lipid A) and a polysaccharide composed of O-antigen, outer core and inner core joined by a covalent bond; they are found in the outer membrane of Gram-negative bacteria, and elicit strong immune responses in animals.
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
