MCQOPTIONS
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MCQOPTIONS
This section includes 697 Mcqs, each offering curated multiple-choice questions to sharpen your Biology knowledge and support exam preparation. Choose a topic below to get started.
| 651. |
Regarding oxygen transport: |
| A. | Haemoglobin S has glutamic acid instead of valine in the chains |
| B. | the O2 saturation of Hb is the percentage of available binding sites that do not have O2 attached |
| C. | the oxygenated form of Hb is the T state |
| D. | cyanosis is more obvious in anaemic patients |
| E. | normal P50 is 27mmHg |
| Answer» F. | |
| 652. |
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» B. adrenaline | |
| 653. |
Which plasma protein has the greatest thyroxine binding capacity? |
| A. | 1-acid glycoprotein |
| B. | thyroxine-binding pre-albumin |
| C. | albumin |
| D. | thyroxine-binding globulin |
| E. | orosomucoid |
| Answer» D. thyroxine-binding globulin | |
| 654. |
Which plasma protein has the greatest thyroxine-binding affinity? |
| A. | 1-acid glycoprotein |
| B. | thyroxine-binding pre-albumin |
| C. | albumin |
| D. | thyroxine-binding globulin |
| E. | orosomucoid |
| Answer» E. orosomucoid | |
| 655. |
Regarding the secretion of insulin, which statement is INCORRECT? |
| A. | insulin is not required for glucose to enter pancreatic B cells |
| B. | it involves closure of ATP-sensitive potassium channels |
| C. | it is a biphasic process involving two pools of insulin |
| D. | it involves opening of voltage-sensitive calcium channels |
| E. | glucose enters pancreatic B cells by combining with glut 4 |
| Answer» F. | |
| 656. |
Which statement is FALSE regarding CVS? |
| A. | the primary function of the CVS uses convection |
| B. | secondary function involves heat control |
| C. | the heart is two pumps operating in parallel |
| D. | the same volume of blood passes through each semilunar valve over time |
| E. | the Frank Starling mechanism is used in balancing the output of both ventricles |
| Answer» D. the same volume of blood passes through each semilunar valve over time | |
| 657. |
Which is FALSE? Stroke Volume varies with changes in: |
| A. | ventricular contractility |
| B. | arterial pressure |
| C. | end diastolic volume of ventricle |
| D. | blood viscosity |
| E. | right ventricle compared to left |
| Answer» F. | |
| 658. |
In excitation-contraction of skeletal muscle, calcium binds to: |
| A. | tropomyosin |
| B. | myosin |
| C. | troponin I |
| D. | troponin C |
| E. | troponin T |
| Answer» E. troponin T | |
| 659. |
Exercise has all of the following effects on blood gases EXCEPT: |
| A. | increased PACO2 |
| B. | increased PAO2 |
| C. | unchanged PaCO2 |
| D. | unchanged PaO2 |
| E. | increased PvCO2 |
| Answer» B. increased PAO2 | |
| 660. |
The diffusion capacity (DI) of the lung accounts for: |
| A. | P1-P2 |
| B. | area of lung |
| C. | the thickness |
| D. | diffusion constant |
| E. | all of the above |
| Answer» B. area of lung | |
| 661. |
Regarding pressure in circulation, which is FALSE? |
| A. | kinetic energy = M.V2(mass x velocity2)2 |
| B. | hydrostatic (gravitational) pressure = potential energy |
| C. | the pressure in a foot vein may be 150 cm??? greater than at aortic root (in upright posture) |
| D. | the same pressure differential applies in arterial system, (in upright posture) |
| E. | the greatest pressure drop occurs in the capillaries |
| Answer» F. | |
| 662. |
Contraction of skeletal muscle is initiated by Ca++ binding to: |
| A. | tropomyosin |
| B. | myosin |
| C. | actin |
| D. | troponin C |
| E. | troponin I |
| Answer» E. troponin I | |
| 663. |
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» B. skeletal muscle | |
| 664. |
With regard to contraction and relaxation of skeletal muscle, all of the following are true EXCEPT: |
| A. | contraction involves the release of K+ from the terminal cisterns |
| B. | relaxation involves the release of Ca2+ from troponin |
| C. | prior to contraction, increase Na+ and K+ conduction occurs in the end-plate membrane |
| D. | relaxation involves cessation of the interaction between actin and myosin |
| E. | contraction involves inward spread of depolarisation along T tubules |
| Answer» B. relaxation involves the release of Ca2+ from troponin | |
| 665. |
Which of the following substances is NOT actively secreted in to the tubular lumen by the proximal renal tubule? |
| A. | urate |
| B. | para-amino hippuric acid |
| C. | catecholamines |
| D. | sodium |
| E. | creatinine |
| Answer» E. creatinine | |
| 666. |
Which part of the renal tubule is Na+ NOT actively transported out of? |
| A. | proximal convoluted tubule |
| B. | thin portions of the loop of Henle |
| C. | thick ascending limb of loop of Henle |
| D. | distal convoluted tubule |
| E. | collecting duct |
| Answer» C. thick ascending limb of loop of Henle | |
| 667. |
Active transport of Na+/K+ accounts for what percentage of energy utilised in cells and neurons? |
| A. | 20% cells, 50% neurons |
| B. | 24% cells, 50% neurons |
| C. | 24% cells, 70% neurons |
| D. | 30% cells, 70% neurons |
| E. | 30% cells, 90% neurons |
| Answer» D. 30% cells, 70% neurons | |
| 668. |
Which of the following has the greatest effect on the ability of the blood to transport O2? |
| A. | the capacity of the blood to dissolve O2 |
| B. | the amount of Hb in the blood |
| C. | the pH of the plasma |
| D. | the CO2 content of red blood cells |
| E. | the temperature of the blood |
| Answer» C. the pH of the plasma | |
| 669. |
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» D. free T3 and T4 do not affect day to day control of their secretion | |
| 670. |
Regarding the effects of thyroid hormones, which of the following does NOT occur? |
| A. | it increases metabolic rate |
| B. | it directly stimulates sodium-potassium ATPase |
| C. | it increases protein and fat catabolism |
| D. | it increases body temperature |
| E. | it increases cerebral oxygen consumption |
| Answer» F. | |
| 671. |
Nicotinic receptors, which is FALSE? |
| A. | are found on sympathetic ganglia |
| B. | are found at the neuromuscular junction |
| C. | are activated by ACh |
| D. | cause activation of a G protein and cAMP |
| E. | cause influx of Na+ via open Na+ channels |
| Answer» E. cause influx of Na+ via open Na+ channels | |
| 672. |
Regarding visual receptors: |
| A. | rods predominate in the jovea |
| B. | rhodopsin is the primary pigment of rods |
| C. | lie anterior (superficial) to their neural pathway |
| D. | colour blindness is an autosomal recessive gene |
| E. | supplied by retinal vessels |
| Answer» C. lie anterior (superficial) to their neural pathway | |
| 673. |
The transport of which of the following gases is DIFFUSION LIMITED? |
| A. | O2 |
| B. | N2O |
| C. | CO2 |
| D. | CO |
| E. | halothane |
| Answer» E. halothane | |
| 674. |
When a normal innervated skeletal muscle is stretched, the initial response is contraction, but with increasing stretch, the muscle suddenly relaxes because: |
| A. | with strong stretch, the efferent discharge is decreased |
| B. | with strong stretch, the discharge from the annulospiral endings of afferent nerve fibres is inhibited |
| C. | with strong stretch, there is decreased activity in the afferent nerve fibres from the Golgi tendon organs |
| D. | with strong stretch, there is increased activity in the afferent nerve fibres from the Golgi tendon organs |
| E. | because of reciprocal innervation, there is increased discharge in the afferent nerve fibres from the antagonists to the stretched muscle |
| Answer» F. | |
| 675. |
Which of the following tissues possess FEW thyroid hormone receptors? |
| A. | liver |
| B. | testis |
| C. | kidney |
| D. | heart |
| E. | skeletal muscle |
| Answer» C. kidney | |
| 676. |
Substance X is freely filtered by the glomerulus and is not reabsorbed, nor secreted nor metabolized.If - serum x concentration = 0.020 mg/mlrenal artery x concentration = 0.020 mg/mlrenal vein x concentration = 0.002 mg/mlurine x concentration = 14 mg/mlurine flow = 54 ml/hrlymphatic x concentration = 0.00001 mg/mlhaematocrit = 0.45Renal blood flow is: |
| A. | 10.5 ml/min |
| B. | 21.2 ml/min |
| C. | 11.7 ml/min |
| D. | 700 ml/min |
| E. | 1273 ml/min |
| Answer» F. | |
| 677. |
Which thyroid hormone has the longest plasma half-life? |
| A. | T4 |
| B. | DIT |
| C. | MIT |
| D. | T3 |
| E. | RT3 |
| Answer» B. DIT | |
| 678. |
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» C. TSH increases iodine uptake by the thyroid gland | |
| 679. |
Which thyroid hormone possesses the GREATEST biological activity? |
| A. | T4 |
| B. | DIT |
| C. | MIT |
| D. | T3 |
| E. | RT3 |
| Answer» E. RT3 | |
| 680. |
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» D. inner mitochondrial membrane | |
| 681. |
Which of the following is transported via active transport? |
| A. | chloride |
| B. | hydrogen |
| C. | glucose |
| D. | urea |
| E. | bicarbonate |
| Answer» C. glucose | |
| 682. |
Type I muscle fibres: |
| A. | have fast glycolytic rates |
| B. | have low oxidative capacity |
| C. | are more commonly found in muscle that performs explosive work |
| D. | do not have a very high glycolytic capacity |
| E. | are not abundant in endurance athletes |
| Answer» E. are not abundant in endurance athletes | |
| 683. |
Which is NOT resorbed via cotransport with Na+ in the PCT? |
| A. | lactate |
| B. | phosphate |
| C. | hydrogen |
| D. | amino acids |
| E. | collecting duct |
| Answer» D. amino acids | |
| 684. |
Regarding cardiac muscle: |
| A. | gap junctions provide high resistance bridges |
| B. | T system of tubules located at A-I junctions |
| C. | calcium binds to calmodulin |
| D. | tetany is not possible due to the latch bridge mechanism |
| E. | cAMP leads to force of contraction |
| Answer» F. | |
| 685. |
Which iodinated compound is present in GREATEST amounts in the adult thyroid gland? |
| A. | T4 |
| B. | DIT |
| C. | MIT |
| D. | T3 |
| E. | RT3 |
| Answer» B. DIT | |
| 686. |
Which of the following agents cause relaxation of mesangial cells of the glomerulus? |
| A. | angiotensin II |
| B. | dopamine |
| C. | endothelins |
| D. | vasopressin |
| E. | noradrenaline |
| Answer» C. endothelins | |
| 687. |
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» F. | |
| 688. |
Which of the following does NOT act via an intracellular receptor? |
| A. | Cortisol |
| B. | Thyroxine |
| C. | ANP |
| D. | Aldosterone |
| E. | Retinoic acid |
| Answer» D. Aldosterone | |
| 689. |
Toxins that increase the cyclic AMP content of the intestinal mucosa cause diarrhoea because they: |
| A. | increase Cl- secretion into the intestinal lumen |
| B. | increase Na+ absorption in the small intestine |
| C. | increase K+ secretion into the colon |
| D. | increase Na+/K+ co-transport K+ secretion into the colon |
| E. | none of the above |
| Answer» B. increase Na+ absorption in the small intestine | |
| 690. |
Which of the following does NOT increase pancreatic polypeptide secretion? |
| A. | protein ingestion |
| B. | fasting |
| C. | exercise |
| D. | acute hypoglycaemia |
| E. | intravenous glucose |
| Answer» F. | |
| 691. |
Which of the following does not increase the length of ventricular cardiac muscle fibres? |
| A. | increased total blood volume |
| B. | increased venous tone |
| C. | increased pumping action of skeletal muscle |
| D. | increased negative intrathoracic pressure |
| E. | increased intrapericardial pressure |
| Answer» F. | |
| 692. |
Creatinuria occurs in measurable amounts in all but: |
| A. | women during and after pregnancy and occasionally in non-pregnant women |
| B. | normal men |
| C. | starvation |
| D. | thyrotoxicosis |
| E. | poorly controlled diabetes mellitus |
| Answer» C. starvation | |
| 693. |
Which of the following does not cause a systolic murmur? |
| A. | aortic stenosis |
| B. | anaemia |
| C. | mitral insufficiency |
| D. | tricuspid stenosis |
| E. | normal flow in children |
| Answer» E. normal flow in children | |
| 694. |
Adrenal insufficiency may cause all but which of the following? |
| A. | inability to excrete a water load |
| B. | personality changes |
| C. | sodium loss with circulatory insufficiency |
| D. | hypoglycaemia in the presence of fasting |
| E. | leukocytosis |
| Answer» F. | |
| 695. |
Uric acid is formed by the breakdown of: |
| A. | purines |
| B. | pyrimidines |
| C. | glutamine |
| D. | urea |
| E. | all of the above |
| Answer» B. pyrimidines | |
| 696. |
In the adrenal medulla: |
| A. | epinephrine is formed by the hydroxylation and decarboxylation of tyrosine |
| B. | 10% of the cells are the epinephrine-secreting type |
| C. | plasma norepinephrine levels are generally unchanged after adrenalectomy |
| D. | catecholamine t1/2 is 10 minutes in the circulation |
| Answer» D. catecholamine t1/2 is 10 minutes in the circulation | |
| 697. |
How many ATP molecules are produced from one molecule of a 6-carbon fatty acid metabolised via the TCA cycle to carbon dioxide and water? |
| A. | 36 |
| B. | 38 |
| C. | 40 |
| D. | 42 |
| E. | 44 |
| Answer» F. | |