-
Question 1
Incorrect
-
After exercise, O2 debt repay may take up to:
Your Answer: 12 hrs
Correct Answer: 90 min
Explanation:Physical activity or exercise requires oxygen for production of ATP or energy via aerobic pathways of energy production. When the amount of oxygen that reaches muscles depletes, cells start producing energy anaerobically by partial breakdown of glucose resulting in lactic acid. Lactic acid should be removed from cells as it causes muscle fatigue. Oxygen is needed to oxidize lactic acid in to carbon dioxide and water and this need is known as oxygen debt. The existence of an oxygen debt explains why we continue to breathe deeply and quickly for a while after exercise. This may take up from 60 – 90 mins.
-
This question is part of the following fields:
- Medicine
- Respiratory
-
-
Question 2
Incorrect
-
A 25-year-old woman presented to the ED with carbon monoxide poisoning. High-flow oxygen was administered immediately. She had a GCS of 15 and her vitals were stable. Which one of the following is not an indication for hyperbaric oxygen therapy in this scenario?
Your Answer: Extrapyramidal features
Correct Answer: A carboxyhaemoglobin concentration of 16%
Explanation:Carbon monoxide (CO) poisoning, considered as the great imitator of other diseases, as the patients present with a myriad of symptoms. The carbon monoxide diffuses rapidly across the pulmonary capillary membrane binding to the haem molecule with a very high affinity (240 times that of oxygen) forming carboxy-haemoglobin (COHb). Non-smokers have a baseline COHb of ,3% while smokers have a baseline COHb of 10-15%.Use of Hyperbaric oxygen therapy (HBOT) for treatment of mild to moderate CO poisoning is not routine.The selection criteria for HBOT in cases of CO poisoning include:• COHb levels > 20-25%• COHb levels > 20% in pregnant patient • Loss of consciousness• Severe metabolic acidosis (pH <7.1)• Evidence of end-organ ischemia (e.g., ECG changes, chest pain, or altered mental status)Principle of HBOT:Exposing patients to 100 percent oxygen under supra-atmospheric conditions results in a decrease in the half-life (t1/2) of COHb, from , 90 min in atmospheric air to , 30 minutes. The amount of oxygen dissolved in the blood also rises from , 0.3 to 6 mL/dL, increasing the delivery of non-haemoglobin-bound oxygen to the tissues.
-
This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 3
Incorrect
-
Which one of these features is typical of dermatomyositis?
Your Answer: Heliotrope rash around external auditory meatus
Correct Answer: Gottron's papules over knuckles of fingers
Explanation:Dermatomyositis is a long-term inflammatory disorder which affects muscles. Its symptoms are generally a skin rash and worsening muscle weakness in the proximal muscles (for example, the shoulders and thighs) over time. These may occur suddenly or develop over months. Other symptoms may include weight loss, fever, lung inflammation, or light sensitivity. Complications may include calcium deposits in muscles or skin.The skin rash may manifest as aheliotrope (a purplish color) or lilac, but may also be red. It can occur around the eyes along with swelling, as well as the upper chest or back ( shawl sign) or V-sign above the breasts and may also occur on the face, upper arms, thighs, or hands. Another form the rash takes is called Gottron’s sign which are red or violet, sometimes scaly, slightly raised papules that erupt on any of the finger joints (the metacarpophalangeal joints or the interphalangeal joints)
-
This question is part of the following fields:
- Dermatology
- Medicine
-
-
Question 4
Incorrect
-
What is the average life span of red blood cells?
Your Answer: 7 hours
Correct Answer: 4 months
Explanation:Approximately 2.4 million new erythrocytes are produced per second in human adults. The cells develop in the bone marrow and circulate for about 100–120 days (4 months) in the body before their components are recycled by macrophages.
-
This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 5
Correct
-
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.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 6
Incorrect
-
With regards to the deiodinases, where would you find D1?
Your Answer: Pituitary gland
Correct Answer: Liver
Explanation:The liver produces an important amount of T3 by outer ring deiodination thanks to its elevated concentration of type I deiodinase. It can also be found in the kidney.
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 7
Incorrect
-
Southern Blotting and DNA probes:
Your Answer: Localisation of native nucleic acid sequences within cells is part of insitu hybridisation
Correct Answer: DNA fragments are separated by gel electrophoresis and transferred onto membrane sheets in 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.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 8
Incorrect
-
Which of the following makes up the thick filaments in muscle fibers?
Your Answer: Tropomyosin
Correct Answer: Myosin
Explanation:The thick filaments are made up of myosin and the thin filaments are made up of actin. The thick filaments are twice the size of the thin filaments and are aligned to form the A band. The thin filaments extending out from the A band form the less dense I bands.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 9
Incorrect
-
A 50-year-old male was brought to the ER after the accidental consumption of 300 ml of diethylene glycol. Blood investigations were suggestive of metabolic acidosis and renal failure. What is the appropriate management in this patient?
Your Answer:
Correct Answer: Haemodialysis and oral ethanol
Explanation:Among the given options the most appropriate management in this patient would be ethanol and haemodialysis.Ethanol competes with ethylene glycol for alcohol dehydrogenase and thus, helps manage a patient with ethylene glycol toxicity.Ethylene glycol is a type of alcohol used as a coolant or antifreezeFeatures of toxicity are divided into 3 stages:Stage 1: (30 min to 12 hours after exposure) Symptoms similar to alcohol intoxication: confusion, slurred speech, dizziness (CNS depression)Stage 2: (12 – 48 hours after exposure) Metabolic acidosis with a high anion gap and high osmolar gap. Also tachycardia, hypertensionStage 3: (24 – 72 hours after exposure) Acute renal failureManagement has changed in recent times:Fomepizole, an inhibitor of alcohol dehydrogenase, is now used first-line in preference to ethanol.Ethanol has been used for many years works by competing with ethylene glycol for the enzyme alcohol dehydrogenase this limits the formation of toxic metabolites (e.g. glycolaldehyde and glycolic acid) which are responsible for the hemodynamic/metabolic features of poisoning.Haemodialysis has a role in refractory cases.
-
This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 10
Incorrect
-
A 50-year-old patient was started on ezetimibe, for his cholesterol a few days back. Which among the following statements is true regarding ezetimibe?
Your Answer:
Correct Answer: Its principal action is to reduce intestinal cholesterol absorption
Explanation:Ezetimibe is a cholesterol-lowering agent that acts to prevent cholesterol absorption by directly inhibiting cholesterol receptors on enterocytes.It does not affect the absorption of drugs (e.g. digoxin, thyroxine) or fat-soluble vitamins (A, D and K) as the anion-exchange resins do. It does not affect the cytochrome P450 enzyme system.The increased risk of myositis associated with the statins is not seen with ezetimibe.The most common adverse effects include headache, runny nose, and sore throat. Less common reactions include body aches, back pain, chest pain, diarrhoea, joint pain, fatigue, and weakness.
-
This question is part of the following fields:
- Medicine
- Pharmacology
-
-
Question 11
Incorrect
-
Which statement is correct?
Your Answer:
Correct Answer: MtDNA principally encodes for proteins that are involved in oxidative phosphorylation for the production of ATP in the cell.
Explanation:Mitochondria have no nucleus instead they contain their own free floating circular genome (MtDNA), which encodes 13 different subunits of proteins involved in oxidative phosphorylation. The remainder of the mitochondrial proteins are nuclear encoded, synthesized in the cytoplasm, and transported into the mitochondria.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 12
Incorrect
-
The immunoglobulin found in the highest concentration in humans is
Your Answer:
Correct Answer: IgG
Explanation:Representing approximately 75% of serum antibodies in humans, IgG is the most common type of antibody found in the circulation. IgG molecules are created and released by plasma B cells.
-
This question is part of the following fields:
- Immunology
- Medicine
-
-
Question 13
Incorrect
-
Which of the following provides the sympathetic nervous supply to the stomach?
Your Answer:
Correct Answer: Coeliac plexus
Explanation:Parasympathetic innervation to the stomach is from the vagus nerve and the sympathetic innervation is from the coeliac plexus.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 14
Incorrect
-
Which mechanism of action does Penicillin use?
Your Answer:
Correct Answer: Inhibit cell wall synthesis
Explanation:Bacteria constantly remodel their peptidoglycan cell walls, simultaneously building and breaking down portions of the cell wall as they grow and divide. β-Lactam antibiotics inhibit the formation of peptidoglycan cross-links in the bacterial cell wall; this is achieved through binding of the four-membered β-lactam ring of penicillin to the enzyme DD-transpeptidase. As a consequence, DD-transpeptidase cannot catalyse formation of these cross-links, and an imbalance between cell wall production and degradation develops, causing the cell to rapidly die.
-
This question is part of the following fields:
- Infectious Diseases
- Medicine
-
-
Question 15
Incorrect
-
Which is true of the composition of bile in the human hepatic duct?
Your Answer:
Correct Answer: Contains only actively secreted substances
Explanation:Hepatic bile is an isotonic fluid and its electrolyte composition resembles that of plasma. 97% of water is found in the gallbladder bile, not hepatic duct. Hepatic bile is alkaline. The ratio of bile acids: phosphatidylcholine: cholesterol is 20:1:3. Hepatic bile contai9ns only actively secreted substances.
-
This question is part of the following fields:
- Hepatobiliary
- Medicine
-
-
Question 16
Incorrect
-
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:
Correct 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.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 17
Incorrect
-
Which ion channel does not contribute to the myocardial action potential?
Your Answer:
Correct Answer: Chloride channel
Explanation:The upstroke in the cardiac action potential is due to opening of the sodium channels and an influx of sodium into the cell. The initial repolarization phase is due to transient opening of the potassium channels along with calcium channels. Influx of calcium causes the prolonged plateau phase of the action potential. Delayed opening of the rectifier potassium channel and delayed closure of the calcium channel leads to the repolarization phase of cardiac action potential.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 18
Incorrect
-
Changes in cadherin expression are associated with
Your Answer:
Correct Answer: Tumour metastatic potential
Explanation:Cadherins play a role in maintaining cell and tissue structure, and in cellular movement. The E-cadherin–catenin complex plays a key role in cellular adhesion; loss of this function has been associated with greater tumour metastasis.
-
This question is part of the following fields:
- Cell Biology
- Medicine
-
-
Question 19
Incorrect
-
Which of the following is the most common causative organism in infective endocarditis?
Your Answer:
Correct Answer: Streptococcus viridans
Explanation:Viridans Alpha-haemolytic streptococci, that are present in the mouth are the most frequently isolated microorganisms when the infection is acquired in a community setting. In contrast, Staphylococcus blood stream infections are frequently acquired in a health care setting where they can enter the blood stream through procedures that cause break in the integrity of skin like surgery, catheterisation or during access of long term indwelling catheters or secondary to intravenous injection of recreational drugs.Prosthetic valve endocarditis is commonly caused by Staphylococcus epidermidis as it is capable of growing as a biofilm on plastic surfaces
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 20
Incorrect
-
Cells mediating innate immunity include:
Your Answer:
Correct Answer: Natural killer cells
Explanation:Natural killer cells have features of both innate and adaptive immunity. They play an important part in defence against tumours and viruses. They are non specific and do not generate immunological memory
-
This question is part of the following fields:
- Immunology
- Medicine
-
-
Question 21
Incorrect
-
In Restriction Fragment Length Polymorphism (RFLP), the DNA fragments are separated by length through a process known as:
Your Answer:
Correct Answer: Gel electrophoresis
Explanation:Samples of DNA from individuals are broken into pieces by restriction enzymes and the fragments are separated according to their lengths via gel electrophoresis. Although now largely obsolete due to the rise of inexpensive DNA sequencing technologies, RFLP analysis was the first DNA profiling technique inexpensive enough to see widespread application.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 22
Incorrect
-
A 45 year old male presents with lower backache and pain in his hips. Blood tests are normal except for elevated serum alkaline phosphatase which is 1200 IU/l (45-105). Radiological examination shows combined osteolytic and osteosclerotic lesions. What is the most common site of occurrence of this disease?
Your Answer:
Correct Answer: Pelvis
Explanation:The patient most likely suffers from Paget’s disease of the bone as his radiological examination shows both osteolytic and osteosclerotic lesions. Any bone or bones can be affected, but Paget’s disease occurs most frequently in the pelvis > lumbar spine > femur > thoracic spine > sacrum > skull > tibia.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 23
Incorrect
-
The celiac trunk consists of which arteries?
Your Answer:
Correct Answer: Left gastric, common hepatic, splenic
Explanation:The celiac trunk is the first major branch of the abdominal aorta. It is 1.25 cm in length. Branching from the aorta at thoracic vertebra 12 (T12). There are three main divisions of the celiac artery:- left gastric artery- common hepatic artery- splenic artery
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 24
Incorrect
-
Bile contains:
Your Answer:
Correct Answer: Bile acids, phosphatidylcholine, cholesterol
Explanation:The main components of bile include bile acids or bile salts, phospholipids; mainly phosphatidylcholine, cholesterol, bilirubin, inorganic salts; potassium, sodium and bicarbonate.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 25
Incorrect
-
Which of the following factors is directly responsible for the breakdown of fibrinogen to fibrin?
Your Answer:
Correct Answer: Thrombin
Explanation:Prothrombin (coagulation factor II) is proteolytically cleaved to form thrombin in the coagulation cascade, the clotting process. Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalysing many other coagulation-related reactions.
-
This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 26
Incorrect
-
In the menstrual cycle, ovulation is triggered by:
Your Answer:
Correct Answer: A pituitary LH surge due to the positive feedback effect of circulating oestrogens
Explanation:FSH and LH are secreted to start the development of a follicle at the start of each menstrual cycle. A surge in oestrogen causes a positive feedback in the LH cells of the pituitary; this causes ovulation.
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 27
Incorrect
-
In a 60kg adult male with normal mean arterial pressure and oxygen consumption, what proportion of the cardiac output at rest goes to the brain?
Your Answer:
Correct Answer: 10-15%
Explanation:The rate of cerebral blood flow in the adult is typically 750 millilitres per minute, which is 10-15% of the cardiac output. On average around 13.9% of cardiac output is distributed to the brain.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 28
Incorrect
-
A 28 year old woman presents with painful genital ulceration. She reports that these attacks have been recurrent over the past 4 years. She has been treated previously with oral acyclovir but this has had little effect on the duration of her symptoms. Over the past year, she has noticed almost weekly attacks of mouth ulcers that heal slowly. Past medical history is significant for treatment of thrombophlebitis two years ago. Which of the following is the most likely diagnosis?
Your Answer:
Correct Answer: Behcet's syndrome
Explanation:Behçet disease is a rare vasculitic disorder that is characterized by a triple-symptom complex of recurrent oral aphthous ulcers, genital ulcers, and uveitis. The systemic manifestations can be variable. Ocular disease has the greatest morbidity, followed by vascular disease generally from active vasculitis. Cutaneous manifestations can occur in up 75% of patients with Behcet disease and can range from acneiform lesions, to nodules and erythema nodosum. GI manifestations can be severe. Differentiating Behçet disease from active inflammatory bowel disease can be clinically difficult. Herpes would have ideally responded to acyclovir. Sarcoidosis does not have genital and oral ulcerations.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 29
Incorrect
-
The growth promoting protein anabolic effects of insulin are mediated by:
Your Answer:
Correct Answer: Phosphatidylinositol 3-kinase
Explanation:Phosphatidylinositol 3-kinase or PI-3Ks are a group of enzymes which are involved in a number of different cellular functions. PI-3Ks interact with insulin and the insulin receptor substrate, regulating glucose uptake. They are an important element in the insulin signalling pathway.
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 30
Incorrect
-
Eosinophils provide immunity against
Your Answer:
Correct Answer: Multi cellular parasites
Explanation:Eosinophils, are a variety of white blood cells and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates.
-
This question is part of the following fields:
- Immunology
- Medicine
-
SESSION STATS - PERFORMANCE PER SPECIALTY
