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Question 1
Correct
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Regarding taste threshold and intensity discrimination:
Your Answer: 30% change in concentration of substance tasted is necessary before an intensity difference can be detected
Explanation:The ability of humans to differentiate differences in intensity of taste is poor. A 30% change in the concentration of the substance being tasted is required before an intensity difference is perceived.
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This question is part of the following fields:
- Medicine
- Neurology
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Question 2
Correct
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The areas of extensive series of sarcoplasmic folds known as intercalated discs always occur at what portion of the muscle fiber?
Your Answer: Z lines
Explanation:The muscle fibers of the heart branch and interdigitate, but one complete unit is surrounded by a cell membrane. The place where one muscle fiber abuts the other, the cell membrane of both the fibers run parallel to each other through a series of extensive folds. These areas always occur on the Z lines and are known as intercalated discs.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 3
Incorrect
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Mean intra pleural pressure at rest with inspiration can reach:
Your Answer: -10 mmHg
Correct Answer: -6 mmHg
Explanation:It is a negative pressure as it is lower than the atmospheric pressure. It can start from -2.5 and reach around -6 mmHg
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This question is part of the following fields:
- Medicine
- Respiratory
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Question 4
Incorrect
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The interior of lysosomes is kept at a pH of around 5 by the action of:
Your Answer: Na/H exchanger
Correct Answer: H+ ATPase
Explanation:The lysosome maintains its pH differential by pumping in protons (H+ ions) from the cytosol across the membrane via proton pumps and chloride ion channels. Vacuolar H+-ATPases are responsible for transport of protons, while the counter transport of chloride ions is performed by ClC-7 Cl−/H+ antiporter.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 5
Correct
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Select the correct statement regarding cholecystokinin (CCK):
Your Answer: It causes gallbladder contraction and pancreatic enzyme secretion.
Explanation:CCK has a primary action of increasing the motility of the gallbladder by contracting the muscles in the mucosa of the gall bladder. Apart from this, it augments the action of secretin, resulting in the production of an alkaline pancreatic juice. It increases the synthesis of enterokinase, inhibits gastric emptying and may also enhance the motility of the small intestine and colon. It is released (secreted) by your small intestine during the digestive process. It’s sometimes called pancreozymin.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 6
Incorrect
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The hyperpolarization phase of pacemaker cells is dominated by ____ current.
Your Answer: Ca++
Correct Answer: K+
Explanation:The hyperpolarization phase is a continuation of the repolarization phase but the membrane potential dips below the resting membrane potential. This results due to the fact that the K+ channels take a longer time to close than the Na+ channels. Hence efflux of the K+ will result in hyperpolarization.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 7
Correct
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Which one of the following transporters is involved in facilitated diffusion?
Your Answer: GLUT2
Explanation:GLUT 2 is a bidirectional transporter, allowing glucose to flow in 2 directions via facilitated diffusion. Is expressed by renal tubular cells, liver cells and pancreatic beta cells. It is also present in the basolateral membrane of the small intestine epithelium.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 8
Incorrect
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Which of the following skin conditions is not associated with diabetes mellitus?
Your Answer: Scleroderma
Correct Answer: Sweet's syndrome
Explanation:Diabetic dermadromes constitute a group of cutaneous conditions commonly seen in people with diabetes with longstanding disease. Conditions included in this group are:- Acral dry gangrene- Carotenosis- Diabetic dermopathy- Diabetic bulla- Diabetic cheiroarthropathy- Malum perforans- Necrobiosis lipoidica- Limited joint mobility- Scleroderma- Waxy skin is observed in roughly 50%. Sweet’s syndrome is also known as acute febrile neutrophilic dermatosis has a strong association with acute myeloid leukaemia. It is not associated with diabetes mellitus.
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This question is part of the following fields:
- Dermatology
- Medicine
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Question 9
Incorrect
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Which part of the chromosome plays a role in preserving its integrity and stability?
Your Answer: Centromere
Correct 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 10
Correct
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Bile salts are responsible for:
Your Answer: The emulsification of fats
Explanation:The main function of bile acids is to allow digestion of dietary fats and oils by acting as a surfactant that emulsifies them into micelles, allowing them to be colloidally suspended in the chyme before further processing.
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This question is part of the following fields:
- Hepatobiliary
- Medicine
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Question 11
Incorrect
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An 80-year-old woman with advanced COPD has been admitted to the medicine ward in an unconscious state. She appears to have an acute lower respiratory tract infection. After consulting with an anaesthesiologist it was concluded that she was not a candidate for intensive care unit admission and thus, a decision was made to start the patient on doxapram therapy. Which of the following best fits the characteristics of doxapram?
Your Answer: It is compatible in infusion with aminophylline
Correct Answer: It is contraindicated in hyperthyroidism
Explanation:The two statements that fit the characteristics of doxapram are, epilepsy is a contraindication for doxapram use and concurrent use with theophylline may increase agitation.Doxapram is a central respiratory stimulant. In clinical practice, doxapram is usually used for patients who have an acute exacerbation of chronic obstructive pulmonary disease (COPD) who are unsuitable for admission to the intensive therapy unit for ventilatory support. Doxapram infusion may buy an extra 24 h to allow for recovery.Contraindications include: ischaemic heart disease, epilepsy, cerebral oedema, acute stroke, asthma, hypertension, hyperthyroidism, and pheochromocytoma. The infusion may worsen agitation and dyspnoea and lead to hypertension, nausea, vomiting and urinary retention.Drug interactions:Concomitant administration of doxapram and aminophylline (theophylline) can cause increased skeletal muscle activity, agitation, and hyperactivity.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 12
Incorrect
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Which lipoprotein contains the most cholesterol esters?
Your Answer: VLDL
Correct Answer: LDL
Explanation:LDL and HDL transport both dietary and endogenous cholesterol in the plasma, but LDL is the main transporter of cholesterol and cholesteryl esters.
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This question is part of the following fields:
- Medicine
- Metabolism
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Question 13
Correct
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A 20-year-old male presents to the emergency department about 4 hours after ingesting 20g of paracetamol. N-acetyl cysteine was started immediately. What is the mechanism of action of N-acetyl cysteine?
Your Answer: Replenishes glutathione
Explanation:N-acetylcysteine depletes glutathione reserves by providing cysteine, which is an essential precursor in glutathione production.Glutathione within the liver can normally detoxify these minuscule quantities of NAPQI and prevent tissue damage.N-acetylcysteine (NAC) is the mainstay of therapy for acetaminophen toxicity.Paracetamol overdose:The liver normally conjugates paracetamol with glucuronic acid/sulphate. During an overdose, the conjugation system becomes saturated leading to oxidation by cytochrome P450 (predominately CYP2E1) mixed-function oxidases. This produces a toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI).Normally glutathione acts as a defence mechanism by conjugating with the toxin forming the non-toxic mercapturic acid. If glutathione stores run-out, the toxin forms covalent bonds with cell proteins, denaturing them and leading to cell death.Other uses: In COPD, cystic fibrosis, and other lung conditions, nebulized NAC has mucolytic, anti-inflammatory, and antioxidant properties.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 14
Correct
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Which caspase is part of both the intrinsic and extrinsic apoptotic pathways?
Your Answer: Caspase-3
Explanation:Once initiator caspases are activated in both the intrinsic and extrinsic pathway, they produce a chain reaction, activating several other executioner caspases (Caspase 3, Caspase 6 and Caspase 7).
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 15
Incorrect
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A 68 year old female is on long term prednisolone therapy for polymyalgia rheumatica. Which of the following would be the most suitable protection against osteoporosis?
Your Answer: Calcium and vitamin D
Correct Answer: Oral bisphosphonate
Explanation:Prevention of osteoporosis associated with chronic glucocorticoid therapy is done by administrating bisphosphonates. Oral bisphosphonates are indicated for patients aged above 65 who have been on steroid therapy for over 3 months, so as to reduce the risk of steroid induced osteoporosis. HRT is usually done in post menopausal women who have oestrogen related bone resorption.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 16
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 17
Correct
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The transport of the di- and tri-peptides into enterocytes is by:
Your 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 18
Correct
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The end product of trehalase action on oligosaccharides is
Your Answer: Two glucose molecules
Explanation:Disaccharides are glycoside hydrolases, enzymes that break down certain types of sugars called disaccharides into simpler sugars called monosaccharides.Examples of disaccharides:Lactase (breaks down lactose into glucose and galactose)Maltase (breaks down maltose into 2 glucoses)Sucrase (breaks down sucrose into glucose and fructose)Trehalase (breaks down trehalose into 2 glucoses)
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 19
Correct
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Where in the gastrointestinal tract are valvulae conniventes?
Your Answer: Jejunum
Explanation:The circular folds (valves of Kerckring or valvulae conniventes) are large valvular flaps projecting into the lumen of the small intestine.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 20
Incorrect
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Under normal conditions (where n represents the number of chromosome pairs), just before mitosis begins, how many chromosomes are contained in the nucleus of each somatic cell:
Your Answer: 2n
Correct Answer: 4n
Explanation:In a normal somatic cell there are 2n chromosome but in a replicating cell just before mitosis the chromosomes duplicate but are still joined via the centrosome. Thus there are 4n chromosomes. After completion of mitosis the number goes back to 2n.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 21
Correct
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Which is the primary lymphoid organ?
Your Answer: Thymus
Explanation:Lymphoid organs consist of lymph nodes, the thymus, spleen and tonsils. The thymus is the primary lymphoid organ as it is the organ in which the T cells mature.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 22
Correct
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The process by which DNA fragments are separated by gel and transferred onto a membrane sheet is called:
Your Answer: Southern blotting
Explanation:A Southern blot is a method used in molecular biology for detection of a specific DNA sequence in DNA samples. Southern blotting combines transfer of electrophoresis-separated DNA fragments to a filter membrane and subsequent fragment detection by probe hybridization. The other forms of blotting involve the use of RNA and proteins.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 23
Incorrect
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The reflex responses activated by cold are controlled by which area?
Your Answer: Thalamus
Correct Answer: Posterior hypothalamus
Explanation:The posterior nucleus of the hypothalamus is responsible for thermoregulation and thermogenesis. Studies have shown that the neurons in the posterior hypothalamus which mediate the reflex of shivering are sensitive to temperature; damage to this nucleus produces hypothermia.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 24
Incorrect
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When is the blood pressure at its lowest during pregnancy?
Your Answer: Post partum
Correct Answer: Second trimester
Explanation:It is lowest during the second trimester.
Previous studies have reported changes in blood pressure (BP) throughout pregnancy, and it was generally accepted that in clinically healthy pregnant women, BP falls gradually at first trimester, reaching the lowest around 22–24 weeks, rising again from 28 weeks, and reaching preconception levels by 36 weeks of gestation
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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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Water hammer pulse is found in:
Your Answer: Aortic stenosis
Correct Answer: Aortic insufficiency
Explanation:Watson’s water hammer pulse is the medical sign which describes a pulse that is bounding and forceful, rapidly increasing and subsequently collapsing, as if it were the sound of a water hammer that was causing the pulse. A water hammer was a Victorian toy in which a tube was half filled with fluid, the remainder being a vacuum. The child would invert and reinvert the tube; each time the impact of the fluid at each end would sound like a hammer blow. This is associated with increased stroke volume of the left ventricle and decrease in the peripheral resistance leading to the widened pulse pressure of aortic regurgitation.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 26
Incorrect
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A clinical trial is conducted to study the benefits of a new oral medication to improve the symptoms of patients with asthma. In the trial 400 patients with asthma, half were given the new medication and half a placebo. Three months later they are asked to rate their symptoms using the following scale: much improved, slight improvement, no change, slight worsening, significantly worse. What is the most appropriate statistical test to see whether the new medication is beneficial?
Your Answer: Wilcoxon signed-rank test
Correct Answer: Mann-Whitney U test
Explanation:The type of significance test used depends on whether the data is parametric (can be measured, usually normally distributed) or non-parametric.Parametric tests:Student’s t-test – paired or unpaired*Pearson’s product-moment coefficient – correlationNon-parametric tests:Mann-Whitney U test – unpaired dataWilcoxon signed-rank test – compares two sets of observations on a single samplechi-squared test – used to compare proportions or percentagesSpearman, Kendall rank – correlation.The outcome measured is not normally distributed, i.e. it is non-parametric. This excludes the Student’s t-tests. We are not comparing percentages/proportions so the chi-squared test is excluded. The Mann–Whitney U test is a nonparametric test of the null hypothesis that it is equally likely that a randomly selected value from one sample will be less than or greater than a randomly selected value from a second sample.This test can be used to investigate whether two independent samples were selected from populations having the same distribution.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 27
Incorrect
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Which of the following drugs would be the safest to prescribe in a 22 year old man with seropositive rheumatoid arthritis who is planning to start a family?
Your Answer: Sulfasalazine
Correct Answer: Prednisolone
Explanation:Prednisolone although has many undesirable side effects it may be considered relatively safe compared to the drugs that are provided here. Prolonged treatment with sulphasalazine may depress semen quality and cause irreversible infertility. Methotrexate and leflunomide both inhibit purine/pyrimidine synthesis (the former by inhibiting folate metabolism) and are contraindicated in pregnancy or while trying to conceive. In males, a temporary or permanent decrease in sperm count may occur with cyclophosphamide. Because the recovery of fertility after cyclophosphamide therapy is variable, sperm banking should be considered before treatment is begun.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 28
Incorrect
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Regarding integrins, which option is false?
Your Answer: All of the options are true
Correct Answer: Play no role in cell signalling.
Explanation:Integrins are transmembrane receptors that facilitate cell-extracellular matrix (ECM) adhesion. Upon ligand binding, integrins activate signal transduction pathways that mediate cellular signals such as regulation of the cell cycle, organization of the intracellular cytoskeleton, and movement of new receptors to the cell membrane. Integrins are obligate heterodimers, meaning that they have two subunits: α (alpha) and β (beta). Integrins play an important role in cell signalling by modulating the cell signalling pathways of transmembrane protein kinases such as receptor tyrosine kinases (RTK).
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 29
Incorrect
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The cells that secrete pepsinogen and gastric lipase are found in which part of the stomach?
Your Answer: Antrum
Correct Answer: Body and fundus
Explanation:Stomach can be divided in to different regions. Cardia, fundus, body, antrum and pylorus from proximal end to distal end respectively. Cells that secret the inactive form of pepsin or pepsinogen are chief cells and are abundant in the body (corpus) and the fundus region of the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 30
Correct
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Calcium needed for cardiac muscle contraction is made available during which phase of the action potential?
Your Answer: 2
Explanation:It is made available during the plateau phase of the action potential i.e. phase 2. During the plateau phase of the action potential, Calcium from the extracellular fluid enters through the L type of calcium channels. This entry triggers the release of more calcium from the sarcoplasmic reticulum via the ryanodine receptors.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
