McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Biology .
Chapters
| 51. |
Regarding parathyroid hormone, which is NOT true? |
| A. | it decreases plasma phosphate |
| B. | it is secreted by chief cells of he parathyroid glands |
| C. | it is cleared by Kupffer cells of the liver |
| D. | its secretion is regulated by the level of bound Ca++ in plasma |
| E. | it increases bone reabsorption |
| Answer» D. its secretion is regulated by the level of bound Ca++ in plasma | |
| 52. |
Which of the following reduce insulin secretion? |
| A. | acetylcholine |
| B. | GIP |
| C. | glucagon |
| D. | adrenaline |
| E. | β ketoacids |
| Answer» D. adrenaline | |
| 53. |
With regard to the effect of thyroid hormone on the cardiovascular system, which of the following are TRUE? |
| A. | level of noradrenaline are increased |
| B. | β adrenergic receptor affinity is decreased in heart muscle |
| C. | circulating adrenaline levels are decreased |
| D. | thyroid hormone levels alter the ratio of cardiac myosin isoform types |
| E. | none of the above |
| Answer» D. thyroid hormone levels alter the ratio of cardiac myosin isoform types | |
| 54. |
Stimuli that increase aldosterone secretion and do not effect glucocorticoid secretion includes all EXCEPT: |
| A. | low Na+ intake |
| B. | high K+ intake |
| C. | standing |
| D. | secondary hyperaldosteronism |
| E. | haemorrhage |
| Answer» E. haemorrhage | |
| 55. |
Signs and effects of hyperparathyroidism include all EXCEPT: |
| A. | renal stones |
| B. | demineralization of bones |
| C. | Chvostek’s and Trousseau’s signs |
| D. | hypercalcaemia |
| E. | hypophosphataemia |
| Answer» C. Chvostek’s and Trousseau’s signs | |
| 56. |
Glucagon levels are increased by: |
| A. | secretin |
| B. | somatostatin |
| C. | cholecystokinin |
| D. | free fatty acids |
| E. | ketones |
| Answer» C. cholecystokinin | |
| 57. |
Insulin release: |
| A. | is inhibited by raised cyclic AMP in pancreatic β cells |
| B. | is not stimulated by blood glucose levels below 6mmol/l |
| C. | is increased by β adrenergic stimulators |
| D. | is inhibited by phosphor diesterase inhibitors |
| E. | is increased by somatostatin |
| Answer» C. is increased by β adrenergic stimulators | |
| 58. |
Trace elements believed essential to life include all EXCEPT: |
| A. | arsenic |
| B. | cyanide |
| C. | cobalt |
| D. | silicon |
| E. | nickel |
| Answer» B. cyanide | |
| 59. |
Mono-iodotyrosin (MIT) and diiodotyrosin (DIT) molecules: |
| A. | are deiodinated before joining to form T3 and T4 |
| B. | are secreted into plasma alongside T3 and T4 |
| C. | are the inactive metabolites of T3 and T4 |
| D. | are cleaved from thyroglobulin by proteases in lysosomes |
| E. | are usually excreted in the urine |
| Answer» D. are cleaved from thyroglobulin by proteases in lysosomes | |
| 60. |
Calcitonin secretion is stimulated by the following EXCEPT: |
| A. | gastrin |
| B. | somatostatin |
| C. | oestrogen |
| D. | cholecystokinin |
| E. | glucagon |
| Answer» B. somatostatin | |
| 61. |
With regard to gastric acid secretion, all the following are true EXCEPT: |
| A. | acetylcholine stimulates secretion |
| B. | both G protein and direct calcium channels are involved |
| C. | an H+ - K+ antiport transports H+ into the gastric lumen |
| D. | parietal cells have high levels of carbonic anhydrase |
| E. | acid secretion is maintained at constant levels by local feedback mechanisms |
| Answer» E. acid secretion is maintained at constant levels by local feedback mechanisms | |
| 62. |
Tissues in which insulin does NOT facilitate glucose uptake? |
| A. | red blood cells |
| B. | skeletal muscle |
| C. | cardiac muscle |
| D. | smooth muscle |
| E. | aorta |
| Answer» A. red blood cells | |
| 63. |
Regarding the “iodide pump” in thyroid cells, which is NOT true? |
| A. | it is stimulated by TSH |
| B. | it depends on Na+ / K+ ATPase activity |
| C. | it pumps iodide into the colloid, after entering the cell down an electrical gradient |
| D. | it pumps iodide against an electrical gradient |
| E. | its activity can be measured with trace doses of radioactive iodine |
| Answer» C. it pumps iodide into the colloid, after entering the cell down an electrical gradient | |
| 64. |
Which of the following enzymes are missing in the zona glomerulosa? |
| A. | 17 α hydroxylase |
| B. | 11 β hydroxylase |
| C. | 21 β hydroxylase |
| D. | cholesterol desmolase |
| E. | 3 β hydroxysteroid |
| Answer» A. 17 α hydroxylase | |
| 65. |
The effects of hyperthyroidism on the cardiovascular system include all of the following EXCEPT: |
| A. | increased expression of α MHC isoforms in cardiac muscle |
| B. | increased catecholamine plasma levels |
| C. | increased number of β receptors |
| D. | increased affinity of β receptors |
| E. | vasodilation of peripheral vessels |
| Answer» B. increased catecholamine plasma levels | |
| 66. |
Regarding the control of thyroid secretion: |
| A. | free T3 and T4 exert feedback control on anterior pituitary |
| B. | free T3 and T4 exert feedback control on hypothalamus |
| C. | free T3 and T4 exert feedback control on anterior pituitary and hypothalamus |
| D. | free T3 and T4 do not affect day to day control of their secretion |
| E. | the basal metabolic rate is the most important determinant of thyroid secretion |
| Answer» C. free T3 and T4 exert feedback control on anterior pituitary and hypothalamus | |
| 67. |
The following are true of chylomicrons EXCEPT: |
| A. | they are large lipoprotein complexes |
| B. | they are part of the exogenous lipid transport system |
| C. | they enter the circulation via the lymphatic ducts |
| D. | they are cleared from the circulation by lipoprotein lipase on the surface of hepatocytes |
| E. | chylomicron remnants are bound to LDL R and endocytosed |
| Answer» D. they are cleared from the circulation by lipoprotein lipase on the surface of hepatocytes | |
| 68. |
All of the following are true regarding chylomicrons EXCEPT: |
| A. | they contain triglycerides, cholesterol and phospholipids |
| B. | they are formed in the intestinal mucosa |
| C. | they are cleared from the circulation by lipoprotein lipase |
| D. | they are transported to the liver by the portal circulation |
| E. | large numbers after a meal give the plasma a milky appearance |
| Answer» D. they are transported to the liver by the portal circulation | |
| 69. |
The tissue or organ with the greatest potential for increasing the metabolic rate of the body is: |
| A. | liver |
| B. | skin |
| C. | adipose tissue |
| D. | skeletal muscle |
| E. | digestive system |
| Answer» D. skeletal muscle | |
| 70. |
Triglycerides are transported to cells via: |
| A. | chylomicron remnants |
| B. | HDL |
| C. | LDL |
| D. | VLDL |
| E. | none of the above |
| Answer» D. VLDL | |
| 71. |
Regarding vitamin B12 |
| A. | it is a fat soluble vitamin |
| B. | its absorption is inhibited by trypsin |
| C. | it is mainly carried in plasma by attachment to albumin |
| D. | it undergoes enterohepatic circulation |
| E. | none of the above are true |
| Answer» D. it undergoes enterohepatic circulation | |
| 72. |
Regarding HDL: |
| A. | HDL transports ingested cholesterol from the intestine |
| B. | HDL transports triglycerides from peripheral tissues |
| C. | HDL receptors on macrophages are called scavenger receptors |
| D. | elevated HDL levels are associated with increased risk of atherosclerosis |
| E. | none of the above are correct |
| Answer» C. HDL receptors on macrophages are called scavenger receptors | |
| 73. |
Regarding free fatty acids in plasma, which of the following is NOT true? |
| A. | they account for less than 10% of total fatty acids in plasma |
| B. | they are complexed with a protein carrier |
| C. | they can be metabolised to CO2 and water in skeletal and cardiac muscle |
| D. | their level in plasma decreases as plasma adrenaline increases |
| E. | they are converted to energy by the citric acid cycle |
| Answer» D. their level in plasma decreases as plasma adrenaline increases | |
| 74. |
Ubiquitin is: |
| A. | an essential amino acid |
| B. | a polypeptide that tags proteins for degradation |
| C. | a cell membrane glycoprotein |
| D. | a precursor or uric acid |
| E. | none of the above |
| Answer» B. a polypeptide that tags proteins for degradation | |
| 75. |
In a fasting adult at rest: |
| A. | skeletal muscle metabolises mainly glucose |
| B. | the brain accounts for approximately 40% of glucose utilised |
| C. | blood glucose concentrations are higher in women than in men |
| D. | blood glucose levels are maintained initially by hepatic glycogenolysis |
| E. | ketones are absent from plasma |
| Answer» D. blood glucose levels are maintained initially by hepatic glycogenolysis | |
| 76. |
Uric acid handling by the kidneys involves: |
| A. | filtration only |
| B. | secretion by tubules only |
| C. | filtration and secretion |
| D. | filtration and reabsorption |
| E. | filtration, reabsorption and secretion |
| Answer» E. filtration, reabsorption and secretion | |
| 77. |
The following vitamin is fat soluble: |
| A. | niacin |
| B. | B6 |
| C. | K |
| D. | pantothenic acid |
| E. | biotin |
| Answer» C. K | |
| 78. |
With regard to the metabolism of carbohydrates: |
| A. | in the absence of liver glycogen stores, glycogen administration does not cause hyperglycaemia |
| B. | glucocorticoids have a minor effect on gluconeogenesis |
| C. | growth hormone causes increased use of glucose for energy |
| D. | glucose is absorbed by most cells by active sodium glucose co-transport |
| E. | during starvation, stores last for less than 24 hours |
| Answer» E. during starvation, stores last for less than 24 hours | |
| 79. |
With regard to lipid metabolism: |
| A. | only HDL is formed in the liver |
| B. | fatty acids in the plasma form 1:1 complexes with albumin |
| C. | plasma cholesterol levels rise considerably with an increase in daily ingestion |
| D. | free fatty acids are metabolised in preference to glucose in a non-exercising individual |
| E. | utilisation of fatty acids is stimulated by glucocorticoids |
| Answer» E. utilisation of fatty acids is stimulated by glucocorticoids | |
| 80. |
With regard to carbohydrate metabolism: |
| A. | the normal fasting glucose is from 3.9 to 11.0mmol/L |
| B. | glucose is phosphylated in cells to glucose-6-phosphate by phosphoenol-pyrunate carboxykinase |
| C. | glycogen, the storage form of glucose, is only in the liver and skeletal muscle |
| D. | glucose can be converted to fats through acetyl CoA which is irreversible |
| E. | none of the above |
| Answer» D. glucose can be converted to fats through acetyl CoA which is irreversible | |
| 81. |
Which statement regarding glucagon is INCORRECT? |
| A. | it is used as an antidote in symptomatic beta blocker overdosage |
| B. | it is synthesised in the A cells of the pancreatic islets and in small intestinal mucosal cells |
| C. | its major site of metabolism is in the plasma |
| D. | it is synthesised in common with glicentin |
| E. | the exogenous glucagon is associated with nausea and vomiting |
| Answer» C. its major site of metabolism is in the plasma | |
| 82. |
Which of the following is NOT an action of somatostatin? |
| A. | it inhibits glucagon secretion |
| B. | it is a synaptic transmitter in the retina |
| C. | it inhibits insulin secretion |
| D. | it increases contraction of the gallbladder |
| E. | it inhibits pancreatic polypeptide secretion |
| Answer» D. it increases contraction of the gallbladder | |
| 83. |
Glucagon increases the secretion of all of the following EXCEPT: |
| A. | catecholamines from a phaeochromocytoma |
| B. | atrial natriuretic peptide |
| C. | growth hormone |
| D. | insulin |
| E. | calcitonin from a medullary carcinoma of the thyroid |
| Answer» B. atrial natriuretic peptide | |
| 84. |
Regarding the actions of glucagon, which of the following is INCORRECT? |
| A. | it increases blood lactate level |
| B. | it activates hormone-sensitive lipase |
| C. | it has a positive inotropic effect on myocardium |
| D. | large amounts cause intestinal relaxation |
| E. | it decreases renal tubular sodium reabsorption |
| Answer» A. it increases blood lactate level | |
| 85. |
Which of the following does NOT increase pancreatic polypeptide secretion? |
| A. | protein ingestion |
| B. | fasting |
| C. | exercise |
| D. | acute hypoglycaemia |
| E. | intravenous glucose |
| Answer» E. intravenous glucose | |
| 86. |
Which iodinated compound is present in GREATEST amounts in the adult thyroid gland? |
| A. | T4 |
| B. | DIT |
| C. | MIT |
| D. | T3 |
| E. | RT3 |
| Answer» A. T4 | |
| 87. |
Regarding the action of glucagon on the liver, which of the following is INCORRECT? |
| A. | it causes glycogenolysis via activation of adenylate cyclase |
| B. | it decreases metabolism of glucose-6-phosphate |
| C. | it causes glycogenolysis via activation of phospholipase C |
| D. | it increases gluconeogenesis from available amino acids |
| E. | it decreases ketone body formation |
| Answer» E. it decreases ketone body formation | |
| 88. |
Regarding the synthesis of thyroid hormones, which statement is INCORRECT? |
| A. | iodine undergoes rapid oxidation following entry to thyroid cells |
| B. | the “iodine pump” is the major source of iodine for hormone synthesis |
| C. | TSH increases iodine uptake by the thyroid gland |
| D. | thiocyanate and ouabain decrease iodine uptake by the thyroid gland |
| E. | it involves iodination of thyrosine residues in thyroglobulin |
| Answer» B. the “iodine pump” is the major source of iodine for hormone synthesis | |
| 89. |
Which of the following does NOT inhibit secretion of glucagon? |
| A. | ketones |
| B. | α adrenoceptor agonists |
| C. | secretin |
| D. | amino acids |
| E. | somatostatin |
| Answer» D. amino acids | |
| 90. |
Which plasma protein has the greatest thyroxine binding capacity? |
| A. | α 1-acid glycoprotein |
| B. | thyroxine-binding pre-albumin |
| C. | albumin |
| D. | thyroxine-binding globulin |
| E. | orosomucoid |
| Answer» C. albumin | |
| 91. |
Which of the following does NOT increase secretion of glucagon? |
| A. | diabetes mellitus |
| B. | β adrenoceptor agonists |
| C. | GABA |
| D. | starvation |
| E. | exercise |
| Answer» C. GABA | |
| 92. |
Which plasma protein has the greatest thyroxine-binding affinity? |
| A. | α 1-acid glycoprotein |
| B. | thyroxine-binding pre-albumin |
| C. | albumin |
| D. | thyroxine-binding globulin |
| E. | orosomucoid |
| Answer» D. thyroxine-binding globulin | |
| 93. |
Regarding insulin, which statement is INCORRECT? |
| A. | it consists of two polypeptide chains linked by two disulphide bridges |
| B. | the majority of exogenous insulin is metabolised by the liver |
| C. | it is not the only molecule responsible for insulin-like activity in the blood |
| D. | it increases intracellular potassium concentration |
| E. | exercise increases the affinity of its receptors for insulin |
| Answer» B. the majority of exogenous insulin is metabolised by the liver | |
| 94. |
Which iodinated compound is present in the SMALLEST amounts in the adult thyroid gland? |
| A. | T4 |
| B. | DIT |
| C. | MIT |
| D. | T3 |
| E. | RT3 |
| Answer» E. RT3 | |
| 95. |
Which of the following hormones does NOT increase the hepatic output of glucose? |
| A. | growth hormone |
| B. | adrenaline |
| C. | glucagon |
| D. | noradrenaline |
| E. | cortisol |
| Answer» A. growth hormone | |
| 96. |
Which thyroid hormone has the longest plasma half-life? |
| A. | T4 |
| B. | DIT |
| C. | MIT |
| D. | T3 |
| E. | RT3 |
| Answer» A. T4 | |
| 97. |
Regarding the action of insulin on adipose tissue, which of the following is INCORRECT? |
| A. | it induces lipoprotein lipase which actively hydrolyses triglyceride from circulating lipoproteins |
| B. | it reduces circulating free fatty acids |
| C. | it promotes triglyceride storage in adipocytes |
| D. | it directly inhibits intracellular lipase |
| E. | its effects appear to involve phosphorylation of lipases |
| Answer» E. its effects appear to involve phosphorylation of lipases | |
| 98. |
Which of the following tissues possess FEW thyroid hormone receptors? |
| A. | liver |
| B. | testis |
| C. | kidney |
| D. | heart |
| E. | skeletal muscle |
| Answer» B. testis | |
| 99. |
Which glucose transporter is responsible for insulin-mediated glucose uptake in striated muscle and adipose tissue? |
| A. | glut 1 |
| B. | glut 2 |
| C. | glut 3 |
| D. | glut 4 |
| E. | glut 5 |
| Answer» D. glut 4 | |
| 100. |
Where are the receptors located by which thyroid hormones mediate most of their effects? |
| A. | cell membrane |
| B. | outer mitochondrial membrane |
| C. | nuclear chromatin |
| D. | inner mitochondrial membrane |
| E. | cytoplasm |
| Answer» C. nuclear chromatin | |
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