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Question 1
Correct
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Which of the following is an incorrect statement regarding the structure of DNA?
Your Answer: The two strands of DNA are held together by cysteine bonds.
Explanation:The two strands of DNA are held together by hydrogen bonds formed between the nucleotide bases.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 2
Correct
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A son has brought his 72-year-old mother to clinic. He is concerned about her short-term memory problems for the past 10 months. He has to remind her to take her medications and she has had two incidents of falling over in the last 10 months. Which of the following assists in the diagnosis of above condition?
Your Answer: Progressive loss of function
Explanation:The clinical presentation is dementia. To differentiate Alzheimer disease and vascular dementia, the progressive loss of function is important. Progressive loss of function is usually associated with vascular dementia and rest of the responses are associated with Alzheimer disease.
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This question is part of the following fields:
- Geriatrics
- Medicine
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Question 3
Correct
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Which ion channel is a dimer?
Your Answer: Cl- channel
Explanation:A dimer is a chemical structure formed from two similar sub-units. Chloride channels or exchangers are composed of two similar subunits—a dimer—each subunit containing one pore.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 4
Correct
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The ‘c’ wave in JVP corresponds more closely with:
Your Answer: Isovolumetric contraction
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 5
Incorrect
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According to Starling's law of the heart:
Your Answer: Energy of contraction is proportional to the pressure in the left ventricle
Correct Answer: The extent of the preload is proportional to the end-diastolic volume
Explanation:Frank starlings law describes that an increase in the venous return or the end diastolic volume will cause an increase in the stroke volume/ preload and also cardiac output. It stems from the fact that increased venous return will increase the stretch on the ventricular muscle fibers. The sarcomere will stretch a considerable length that is needed for maximum contraction and the development of tension in the muscle fiber. The greater the venous return the greater the cardiac output. This relationship is directly proportional.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 6
Correct
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In a newly diagnosed acromegaly patient, which of the following would you not expect to find?
Your Answer: Hypohidrosis
Explanation:Features of acromegaly may include:
- Soft tissue swelling visibly resulting in enlargement of the hands, feet, nose, lips and ears, and a general thickening of the skin
- Soft tissue swelling of internal organs, notably the heart with associated weakening of its muscularity, and the kidneys, vocal cords (resulting in a characteristic thick, deep voice and slowing of speech)
- Generalized expansion of the skull at the fontanelle, frontal bossing, prognathism with associated macroglossia (enlargement of the tongue) and teeth spacing.
- Hypertrichosis, hyperpigmentation and hyperhidrosis (not hypohidrosis) may occur in these patients as well as carpal tunnel syndrome and impotence.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 7
Correct
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What microscopic changes are visible in an active thyroid gland?
Your Answer: Follicle lining cells are cuboid or columnar.
Explanation:Active follicles are lined by cuboidal or columnar cells; this is because active follicles are smaller and have less colloid. Their cells are tall because they are actively secreting hormones, whereas older follicles have a flat epithelium and are filled with more colloid.
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This question is part of the following fields:
- Endocrinology
- Medicine
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Question 8
Correct
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The role of the hemidesmosome is?
Your Answer: Attaches cells to underlying basal lamina
Explanation:Hemidesmosomes connect the basal surface of epithelial cells via intermediate filaments to the underlying basal lamina. The transmembrane proteins of hemidesmosomes are not cadherins, but another type of protein called integrin.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 9
Correct
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In the malaria life cycle , parasites which remain dormant in the liver are known as :
Your Answer: Hypnozoites
Explanation:The life-cycles of Plasmodium species involve several different stages both in the insect and the vertebrate host. These stages include sporozoites, which are injected by the insect vector into the vertebrate host’s blood. Sporozoites infect the host liver, giving rise to merozoites and (in some species) hypnozoites. These move into the blood where they infect red blood cells. In the red blood cells, the parasites can either form more merozoites to infect more red blood cells, or produce gametocytes which are taken up by insects which feed on the vertebrate host. In the insect host, gametocytes merge to sexually reproduce. After sexual reproduction, parasites grow into new sporozoites, which move to the insect’s salivary glands, from which they can infect a vertebrate host bitten by the insect
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This question is part of the following fields:
- Infectious Diseases
- Medicine
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Question 10
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 11
Incorrect
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A study is carried out to assess the efficacy of a new anti-epileptic drug for children with absence seizures. The total number of the children selected for the study was 400, from which 150 children were assigned to take the new drug and 250 children were assigned in the control group. After a period of four months, only 15 children taking the new drug had a seizure compared to 100 children from the control group who had seizure. What is the correct value regarding the relative risk reduction?
Your Answer:
Correct Answer: 75%
Explanation:Relative risk reduction (RRR) tells you by how much the treatment reduced the risk of bad outcomes relative to the control group who did not have the treatment. In the previous example, the relative risk reduction of fever and rash in the group of the children on the intervention was 40 per cent (1 – 0.6 = 0.4 or 40 per cent). RRR = (EER -CER) / CER = (0.1 – 0.4) / 0.4 = -0.75 or 75% reduction.
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This question is part of the following fields:
- Medicine
- Research Skills
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Question 12
Incorrect
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Southern Blotting and DNA probes:
Your Answer:
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.
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This question is part of the following fields:
- Genetics
- Medicine
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Question 13
Incorrect
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Question 14
Incorrect
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Which of the following statements regarding psoriasis is incorrect?
Your Answer:
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 15
Incorrect
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Where is most of the filtered sodium reabsorbed?
Your Answer:
Correct Answer: Proximal tubule
Explanation:Renal reabsorption of sodium (Na+) is a part of renal physiology. It uses Na-H antiport, Na-glucose symport, sodium ion channels (minor). It is stimulated by angiotensin II and aldosterone, and inhibited by atrial natriuretic peptide. Most of the reabsorption (65%) occurs in the proximal tubule.
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This question is part of the following fields:
- Medicine
- Renal
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Question 16
Incorrect
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Which of the following factors serve to decrease cardiac output?
Your Answer:
Correct Answer: Standing from a lying position
Explanation:Sleep has no effect on the cardiac output. Anxiety, excitement, increased body temperature and pregnancy will increase the cardiac output. Standing from a lying position will decrease the cardiac output transiently.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 17
Incorrect
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A 27-year-old female diagnosed with rheumatoid arthritis has failed to respond to methotrexate and sulfasalazine. Her GP decides to start her on etanercept injections. Which one among the following is an adverse effect associated with the use of etanercept?
Your Answer:
Correct Answer: Reactivation of tuberculosis
Explanation:Among the give options, reactivation of tuberculosis may occur in a patient under treatment with etanercept.Etanercept is a biological TNF inhibit commonly used to control ankylosing spondylitis, juvenile idiopathic arthritis, plaque psoriasis, psoriatic arthritis, and rheumatoid arthritis.Etanercept is a soluble receptor that binds both TNF-alpha and TNF-beta to inhibit the inflammatory response in joints and skin that is characteristic of these autoimmune disorders.The most common adverse effects include infections (viral, bacterial, and fungal – mostly upper respiratory tract infections) and injection site reaction (erythema, itching, pain, swelling, bleeding, bruising).Rarely it can also cause, reactivation of hepatitis B and TB, pneumocystis pneumonia, congestive cardiac failure, Steven-Johnson syndrome, toxic epidermal necrolysis, etc.
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This question is part of the following fields:
- Medicine
- Pharmacology
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Question 18
Incorrect
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The heart rate can be accelerated by:
Your Answer:
Correct Answer: Exercise and thyroid hormones
Explanation:The firing of the SA node will increase due to exercises and as the thyroid hormone has a chronotropic effect on the heart, it too will result in an increase in the heart rate via stimulation of the adrenergic receptors of the heart. As during exercise the sympathetic nervous system is activated, it will directly have an positive chronotropic effect on the heart.
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This question is part of the following fields:
- Cardiovascular
- Medicine
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Question 19
Incorrect
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Interruption of the entero-hepatic circulation causes:
Your Answer:
Correct Answer: The amount of fat in the stool to be increased
Explanation:Enterohepatic circulation refers to the circulation of biliary acids, bilirubin, drugs, or other substances from the liver to the bile, followed by entry into the small intestine, absorption by the enterocyte and transport back to the liver. One of the causes of the interruption of enterohepatic circulation is the resection of the ileum where fat is mainly absorbed. Fat malabsorption results in increased fat in stools. Pale stools and dark urine is caused by obstruction of the biliary ductal system especially the common bile duct where urobilin and stercobilin are formed.
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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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The predominant site in the lymph node where T lymphocytes are found is:
Your Answer:
Correct Answer: Paracortex
Explanation:Paracortex is found between the cortex and the medulla and it is composed of a non-nodular type of arrangement that is mostly made up of T cells.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 21
Incorrect
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Microtubule disassembly:
Your Answer:
Correct Answer: Occurs at the positive and negative end
Explanation:Dynamic instability refers to the coexistence of assembly and disassembly at the ends of a microtubule. The microtubule can dynamically switch between growing and shrinking phases in this region. Although both assembly and disassembly occur at both ends they occur preferentially at the (+) end.
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This question is part of the following fields:
- Cell Biology
- Medicine
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Question 22
Incorrect
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Which hormone results in the production of pancreatic juice rich in enzymes but low in volume?
Your Answer:
Correct Answer: Cholecystokinin
Explanation:Cholecystokinin (CCK) mediates digestion in the small intestine by inhibiting gastric emptying and decreasing gastric acid secretion. It stimulates the acinar cells of the pancreas to release a juice rich in pancreatic digestive enzymes, hence the old name pancreozymin.
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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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Which of the following substances is involved in the respiratory burst by the neutrophil?
Your Answer:
Correct Answer: NADPh oxidase
Explanation:The respiratory burst is a rapid release of reactive oxygen species (ROS) from neutrophils and other phagocytes. This process is crucial for the destruction of pathogens. The key components and enzymes involved in the respiratory burst include:
- NADPH oxidase: This enzyme complex plays a central role in the respiratory burst by converting oxygen (O2) into superoxide anion (O2•-), a reactive oxygen species. This is the initial step in the production of various ROS.
- Superoxide dismutase (SOD): This enzyme converts superoxide anion (O2•-) into hydrogen peroxide (H2O2). While SOD is involved in the pathway, the respiratory burst is initiated by NADPH oxidase.
- Myeloperoxidase (MPO): This enzyme uses hydrogen peroxide (H2O2) to produce hypochlorous acid (HOCl) from chloride ions (Cl-), which is a potent antimicrobial agent. Myeloperoxidase also produces other reactive species using halide ions.
- Catalase: This enzyme degrades hydrogen peroxide (H2O2) into water (H2O) and oxygen (O2). While catalase helps to protect the cell from oxidative damage by breaking down H2O2, it is not involved in the generation of ROS during the respiratory burst.
- Adenylate cyclase: This enzyme is involved in the production of cyclic AMP (cAMP) from ATP and is not directly related to the respiratory burst.
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This question is part of the following fields:
- Immunology
- Medicine
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Question 24
Incorrect
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H+ ions used in the production of acid by parietal cells is produced with the help of which enzyme?
Your Answer:
Correct Answer: Carbonic anhydrase ii
Explanation:Carbonic anhydrase enzyme catalyses the rapid interconversion of carbon dioxide and water to bicarbonate and protons (or vice versa). This is a reversible reaction that takes place in the gastric parietal cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 25
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:
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 26
Incorrect
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The following are synthesized in the liver EXCEPT?
Your Answer:
Correct Answer: Cholecystokinin
Explanation:The liver is responsible for the mainstay of protein metabolism, synthesis as well as degradation. It is also responsible for a large part of amino acid synthesis. The liver plays a role in the production of clotting factors as well as red blood cell production. Some of the proteins synthesized by the liver include coagulation factors I (fibrinogen), II (prothrombin), V, VII, VIII, IX, X, XI, XIII, as well as protein C, protein S and antithrombin. The liver is a major site of production for thrombopoietin, a glycoprotein hormone that regulates the production of platelets by the bone marrow. The liver also produces albumin, the most abundant protein in blood serum and angiotensinogen. Cholecystokinin, previously called pancreozymin, is synthesized and secreted by enteroendocrine cells in the duodenum
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 27
Incorrect
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Question 28
Incorrect
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Which is true of the citric acid cycle?
Your Answer:
Correct Answer: Involves a series of reactions where oxaloacetate is regenerated
Explanation:The cycle consumes acetate (in the form of acetyl-CoA) and water, reduces NAD+ to NADH, and produces carbon dioxide as a waste by-product. The NADH generated by the citric acid cycle is fed into the oxidative phosphorylation (electron transport) pathway. At the end of each cycle, the four-carbon oxaloacetate has been regenerated, and the cycle continues. The net result of these two closely linked pathways is the oxidation of nutrients to produce usable chemical energy in the form of ATP. Acetyl-CoA, is the starting point for the citric acid cycle and in eukaryotic cells, the citric acid cycle occurs in the matrix of the mitochondrion. Though the Krebs cycle does not directly require oxygen, it can only take place when oxygen is present because it relies on by-products and is therefore an aerobic process.
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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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A 23 year old man presents with a painful right elbow and left Achilles tendon. He also gives history of dysuria, fever and conjunctivitis. Examination reveals macules and pustules on his hands. He has returned from a trip to Far East 3 weeks ago and admits to having unprotected sex. Which of the following is the most likely diagnosis?
Your Answer:
Correct Answer: Reactive arthritis
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. The diagnosis is based on clinical features such as patient history and physical examination; there are no specific tests for reactive arthritis. Treatment is primarily symptomatic and consists of the administration of NSAIDs, as most patients recover spontaneously. extraarticular dermatologic manifestations include skin lesions of the glans resembling psoriasis (balanitis circinata); hyperkeratinisation of the palms and soles (keratoderma blenorrhagicum), oral ulcers. Other STDs including HIV, syphilis have different presentations. Psoriatic arthritis is not commonly associated with urethritis and conjunctivitis.
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This question is part of the following fields:
- Connective Tissue
- Medicine
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Question 30
Incorrect
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Cyclic AMP is formed from ATP via which enzyme
Your Answer:
Correct Answer: Adenylate cyclase
Explanation:Cyclic AMP is synthesized from ATP by adenylate cyclase located on the inner side of the plasma membrane and anchored at various locations in the interior of the cell.
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This question is part of the following fields:
- Cell Biology
- Medicine
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SESSION STATS - PERFORMANCE PER SPECIALTY
