-
Question 1
Correct
-
The telomerase is capable of adding several more repeats of telomeres at which end of the guanosine rich region.
Your Answer: 3rd end
Explanation:Telomerase is a reverse transcriptase that uses the RNA template to synthesize DNA in the 5th-3rd direction resulting in extension of the 3rd end and then translocates it to the newly synthesized end. The GT rich strand is thus elongated.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 2
Incorrect
-
Which of the following cells release histamines when they are activated by binding of specific antigens to cell fixed IgE molecules?
Your Answer: Eosinophils
Correct Answer: Basophils
Explanation:Mast cells and basophils both contain granules of vasoactive histamine in their cytosol. Both of them express IgE receptors on their cell surface and upon binding with a specific antigen they release their cytokines including histamine.
-
This question is part of the following fields:
- Immunology
- Medicine
-
-
Question 3
Incorrect
-
Glucose transport in the brain is mediated by:
Your Answer: GLUT 4
Correct Answer: GLUT 1
Explanation:The facilitative glucose transporter mediates the transport of glucose from blood into neurons and glia in the brain. The primary isoforms in the brain are GLUT1 detected at high concentrations.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 4
Correct
-
Which enzyme is deficient in the inborn error of metabolism called galactosemia?
Your Answer: Galactose-1-phosphate uridyl transferase
Explanation:Galactosaemia is a rare genetic autosomal recessive metabolic disorder. Lactose is broken down by the enzyme lactase into glucose and galactose. In individuals with galactosemia, the enzymes needed for further metabolism of galactose (Galactose-1-phosphate uridyltransferase) are severely diminished or missing entirely, leading to toxic levels of galactose 1-phosphate in various tissues.
-
This question is part of the following fields:
- Medicine
- Metabolism
-
-
Question 5
Incorrect
-
Which statement regarding fever is correct:
Your Answer: Interferon alpha is the key cytokine causing fever
Correct Answer: Body temperature is regulated is by a centre in the floor of the third ventricle
Explanation:The hypothalamus is located on the floor of the third ventricle and is the centre of regulation of body temperature. It uses a set point to regulate other body systems as well. Diurnal variation of temperature is not seen in humans. the principal mediator of fever is interleukin I, although interferon alfa also plays a role. Fever can cause rhabdomyolysis or muscle breakdown
-
This question is part of the following fields:
- Infectious Diseases
- Medicine
-
-
Question 6
Correct
-
Which ventral (motor) root is responsible for triceps?
Your Answer: C7
Explanation:Of the nerve fibers that make up the brachial plexus, C7 mainly forms the radial nerve to innervate the triceps muscle, thus innervating the shoulders, elbow, wrist and hand. C7 is responsible for the triceps reflex.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 7
Correct
-
Preload:
Your Answer: Is the degree to which the myocardium is stretched before is contracts
Explanation:Preload is end diastolic volume. It is the degree to which the heart muscle fiber is stretched when it fills up completely just before the heart contracts.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 8
Correct
-
Carcinogens found in cigarette smoke can transform proto-oncogenes to oncogenes through:
Your Answer: Point mutations in genomic DNA
Explanation:80% of the pancreatic cancers are environmentally influenced by smoking which increases the risk by 50%. Mutation can occur in the KRAS, p16, SMAD4, and TP53 genes among other tumour suppression genes. Smoking can be implicated in transformation of all these genes. Apart from KRAS all the genes are inactivated in pancreatic cancer. As KRAS is the most commonly altered gene, mutation occurs as point mutation. As smoking is the most common aetiology in pancreatic cancer, and KRAS is the most important gene that is altered. Most commonly cigarette smoke causes point mutation.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 9
Incorrect
-
The following cells replicate without shortening their telomeres because they express telomerase.
Your Answer: Stem cells
Correct Answer: Germ cells
Explanation:Telomerase activity is seen in germ cells and is absent in somatic cells. Telomeres prevent the chromosomes from shortening and prevent the coding portion of the DNA from being lost, thus allowing the cell to replicate indefinitely. During replication telomeres may be lost resulting in cell death.
-
This question is part of the following fields:
- Genetics
- Medicine
-
-
Question 10
Incorrect
-
Which of the following best describes the cardiac muscle?
Your Answer: Smooth and involuntary
Correct Answer: Striated and involuntary
Explanation:Cardiac muscle (heart muscle) is an involuntary, striated muscle that is found in the walls and histological foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 11
Incorrect
-
An 18 year old boy, thin with a tall stature, and a high arched palate arrives at the hospital with a spontaneous pneumothorax. He is accompanied by his brother who has a similar appearance. You suspect Marfan's Syndrome. The gene encoding which of the following proteins is defective in this condition?
Your Answer: Collagen
Correct Answer: Fibrillin-1
Explanation:A variety of proteins compose the structure of microfibrils, the most prominent of which are the two fibrillins. Fibrillin-1 a scaffolding protein is encoded by FBN1 on human chromosome 15q21 and fibrillin-2 is encoded by FBN2 on 5q23. Mutations in FBN1 produce Marfan syndrome, a pleiotropic autosomal dominant connective tissue disorder with prominent manifestations in the skeleton, eye and cardiovascular system. A number of conditions related to Marfan syndrome are also due to FBN1 mutations.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 12
Correct
-
In Hirschsprung disease which one is incorrect
Your Answer: Due to congenital absence of myenteric and submucosal plexuses
Explanation:During normal prenatal development, cells from the neural crest migrate into the large intestine (colon) to form the networks of nerves called the myenteric plexus (Auerbach plexus) (between the smooth muscle layers of the gastrointestinal tract wall) and the submucosal plexus (Meissner plexus) (within the submucosa of the gastrointestinal tract wall). In Hirschsprung’s disease, the migration is not complete and part of the colon lacks these nerve bodies that regulate the activity of the colon. The affected segment of the colon cannot relax and pass stool through the colon, creating an obstruction.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 13
Correct
-
Which of the following refers to the process of decoding messenger RNA into an amino acid sequence?
Your Answer: Translation
Explanation:Messenger RNA (mRNA) is decoded in a ribosome, outside the nucleus, to produce a specific amino acid chain, or polypeptide. This is known as translation and follows after the process transcription of DNA to RNA in the cell’s nucleus.
-
This question is part of the following fields:
- Medicine
- Metabolism
-
-
Question 14
Correct
-
Regarding gustatory sensation:
Your Answer: The sensory taste buds on the anterior two-thirds of the tongue travel to the chorda tympani branch of the facial nerve
Explanation:There are three morphologically distinct types of taste buds including; circumvallate, fungiform and foliate. Circumvallate are rounded structures arranged in a v on the back of the tongue. The posterior third travels to glossopharyngeal nerve.
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 15
Incorrect
-
In the Fick‘s method of measuring cardiac output, the arterial oxygen content can be measured in a sample obtained from
Your Answer: The aorta
Correct Answer: The pulmonary vein
Explanation:In Fick’s original method, the following variables are measured:VO2, oxygen consumption in ml of pure gaseous oxygen per minute. This may be measured using a spirometer within a closed rebreathing circuit incorporating a CO2 absorberCa, the oxygen concentration of blood taken from the pulmonary vein (representing oxygenated blood)Cv, the oxygen concentration of blood from an intravenous cannula (representing deoxygenated blood)From these values, we know that:VO2 = (CO x Ca) – (CO x Cv)where CO = Cardiac Output, Ca = Oxygen concentration of arterial blood and Cv = Oxygen concentration of mixed venous blood.This allows us to sayCO = VO2/{Ca – Cv}and hence calculate cardiac output.Note that (Ca – Cv) is also known as the arteriovenous oxygen difference.
-
This question is part of the following fields:
- Cardiovascular
- Medicine
-
-
Question 16
Incorrect
-
An important enzyme in renal tissue responsible for the conversion of glutamine to glutamate and the subsequent production of NH4 is called?
Your Answer: Glutamine reductase
Correct Answer: Glutaminase
Explanation:Glutaminase catalyses the following reaction:Glutamine + H2O → Glutamate + NH3
-
This question is part of the following fields:
- Medicine
- Renal
-
-
Question 17
Correct
-
A 22 year old man who has recently returned from a trip to Far East presents with sore eyes and symmetrical joint pain in his knees, ankles and feet. Labs reveal an elevated ESR. The synovial fluid aspirate is sterile and has a high neutrophil count. What is the most likely diagnosis?
Your Answer: Reactive arthropathy
Explanation:Reactive arthritis, (formerly known as Reiter’s syndrome), is an autoimmune condition that occurs after a bacterial infection of the gastrointestinal or urinary tract. It is categorized as a seronegative spondylarthritis because of its association with HLA-B27. Reactive arthritis primarily affects young men and usually presents with musculoskeletal or extra‑articular symptoms. The characteristic triad consists of arthritis, conjunctivitis, and urethritis. Symmetric lower limb arthropathy and a sterile joint aspirate points towards reactive arthropathy.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 18
Incorrect
-
A 35 year old sales representative presents with severe pain going down her neck and right arm. She admits that this pain is worse on sitting and driving for long periods. Past history is significant for two previous road traffic accidents. Examination reveals weakness and sensory loss over C5/C6 nerve distribution. There is pain with neck movement and particularly extension. Which of the following investigations would be the most helpful in this case?
Your Answer: CT scanning
Correct Answer: MRI scan of the cervical spinal cord
Explanation:Cervical radiculopathy is usually due to compression or injury to a nerve root by a herniated disc or degenerative changes. Levels C5 to T1 are the most commonly affected. It is usually, but not always, accompanied by cervical radicular pain, a sharp and shooting pain that travels from the neck and down the upper limb and may be severe. This needs to be differentiated from pain referred from the musculoskeletal (somatic) structures in the neck, which may be aching rather than sharp, and is more severe in the neck than in the upper limb. The neurological signs of cervical radiculopathy depend on the site of the lesion. The patient may have motor dysfunction, sensory deficits or alteration in tendon reflexes. While pain is a common presenting symptom, not all radiculopathies are painful (i.e. only motor deficits may be obvious). CT scanning cannot accurately demonstrate the commonest cause for cervical radiculopathy (disc herniation) without myelography, which requires hospital admission, lumbar puncture and the use of contrast. In patients with cervical radiculopathy, MRI is the imaging technique of choice for the detection of root compression by disc herniation and osteophytes. MRI allows the nerve roots to be directly visualised. Nerve conduction studies are also useful in determining the nerve roots that are involved.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 19
Correct
-
G cells release which of the following substances
Your Answer: Gastrin
Explanation:The G cell is a type of cell in the stomach and duodenum that secretes gastrin. It works in conjunction with gastric chief cells and parietal cells. G cells are found deep within the pyloric glands of the stomach antrum, and occasionally in the pancreas and duodenum. Gastrin-releasing peptide, as well as the presence of amino acids in the stomach, stimulates the release of gastrin from the G cells. Gastrin stimulates enterochromaffin-like cells to secrete histamine. Gastrin also targets parietal cells by increasing the amount of histamine and the direct stimulation by gastrin, causing the parietal cells to increase HCl secretion in the stomach.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 20
Incorrect
-
A 30 year old female has been started on azathioprine after she was found to be intolerant of methotrexate. Routine blood monitoring shows the following values:Hb 7.9 g/dlPlt 97*109/l WBC 2.7*109/l Azathioprine toxicity will most likely to occur in the presence of which of the following?
Your Answer: Alcohol excess
Correct Answer: Thiopurine methyltransferase deficiency
Explanation:Azathioprine therapy can cause acute myelosuppression. Toxicity is in part caused by the incorporation of azathioprine-derived 6-thioguanine nucleotides (6-TGN) into deoxyribonucleic acid (DNA). The enzyme thiopurine methyltransferase (TPMT) plays an important role in azathioprine catabolism.
-
This question is part of the following fields:
- Connective Tissue
- Medicine
-
-
Question 21
Incorrect
-
Arachidonic acid is converted to:
Your Answer: Phospholipase A2
Correct Answer: Prostaglandin H2
Explanation:The enzymes cyclooxygenase-1 and -2 (i.e. prostaglandin G/H synthase 1 and 2 {PTGS1 and PTGS2}) metabolize arachidonic acid to Prostaglandin G2 and prostaglandin H2.
-
This question is part of the following fields:
- Immunology
- Medicine
-
-
Question 22
Incorrect
-
In the normal adult, haematopoiesis is present
Your Answer: Liver and spleen
Correct Answer: Axial skeleton and proximal ends of long bones
Explanation:In children, haematopoiesis occurs in the marrow of the long bones such as the femur and tibia. In adults, it occurs mainly in the pelvis, cranium, vertebrae, and sternum.
-
This question is part of the following fields:
- Haematology
- Medicine
-
-
Question 23
Correct
-
Question 24
Incorrect
-
Which of the following happens when anterograde neurons are stimulated?
Your Answer: Basic electrical rhythm is initiated
Correct Answer: Smooth muscle relaxation ahead of the stimulus
Explanation:Nitric oxide is thought to act as an anterograde neurotransmitter. Nitric oxide causes relaxation of smooth muscles ahead of the stimulus. Clinically it is used as a potent vasodilator.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 25
Incorrect
-
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.
-
This question is part of the following fields:
- Dermatology
- Medicine
-
-
Question 26
Incorrect
-
Medullary chemoreceptors
Your Answer: Monitor PCO2 concentration of arterial blood
Correct Answer: Monitor H+ concentration of the CSF
Explanation:Central chemoreceptors of the central nervous system, located on the ventrolateral medullary surface in the vicinity of the exit of the 9th and 10th cranial nerves, are sensitive to the pH of their environment. These act to detect the changes in pH of nearby cerebral spinal fluid (CSF) that are indicative of altered oxygen or carbon dioxide concentrations available to brain tissues.
-
This question is part of the following fields:
- Medicine
- Respiratory
-
-
Question 27
Correct
-
A 14-year-old girl presents with short stature, webbed neck and primary amenorrhoea.Given the likely clinical diagnosis, which hormone replacement is most crucial over the longer term?
Your Answer: Oestrogen
Explanation:This girl most likely has Turner syndrome (TS) also known as 45,X, a condition in which a female is partly or completely missing an X chromosome. Signs and symptoms vary among those affected. Often, a short and webbed neck, low-set ears, low hairline at the back of the neck, short stature, and swollen hands and feet are seen at birth. Typically, they are without menstrual periods, do not develop breasts, and are unable to have children. Heart defects, diabetes, and low thyroid hormone occur more frequently. Most people with TS have normal intelligence. Many, however, have troubles with spatial visualization such as that needed for mathematics. Vision and hearing problems occur more often. Turner syndrome is not usually inherited from a person’s parents. No environmental risks are known and the mother’s age does not play a role. As a chromosomal condition, there is no cure for Turner syndrome. However, much can be done to minimize the symptoms including prescribing growth hormone, either alone or with a low dose of androgen, and oestrogen replacement therapy which is crucial long term for maintaining good bone integrity, cardiovascular health and tissue health
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 28
Correct
-
The actions of dihydrotestosterone in male reproductive physiology include:
Your Answer: Development of external genitalia in utero and at puberty
Explanation:Dihydrotestosterone mediates the differentiation of the urogenital sinus and genital tubercles, leading to the fusion of the urethral and labial folds; thus, it leads to the development of external genitalia in the male.
-
This question is part of the following fields:
- Endocrinology
- Medicine
-
-
Question 29
Correct
-
The outer and inner surfaces of the arachnoid mater is covered with:
Your Answer: Mesothelial cells
Explanation:The arachnoid mater is one of the three meninges that covers the brain and spinal cord. It is interposed between the two other meninges, the more superficial and much thicker dura mater and the deeper pia mater, from which it is separated by the subarachnoid space. The arachnoid mater consists of a subdural mesothelial layer and a compact central layer
-
This question is part of the following fields:
- Medicine
- Neurology
-
-
Question 30
Incorrect
-
What is the mechanism of action of sildenafil citrate?
Your Answer: Inhibition of cyclo-oxygenase II
Correct 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.
-
This question is part of the following fields:
- Medicine
- Pharmacology
-
SESSION STATS - PERFORMANCE PER SPECIALTY
