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.
| 351. |
Which of the following DOES NOT shift the oxygen-haemoglobin dissociation curve to the right? |
| A. | decreased phosphate |
| B. | increased altitude |
| C. | cortisol |
| D. | decreased pH |
| E. | aldosterone |
| Answer» B. increased altitude | |
| 352. |
Which of the following need to be intact for normal stereognosis: |
| A. | dorsal columns |
| B. | parietal lobe |
| C. | pressure pathways |
| D. | all of the above |
| E. | none of the above |
| Answer» C. pressure pathways | |
| 353. |
All the following statements regarding the atrial natriuretic peptide (ANP) are true EXCEPT: |
| A. | it causes natriuresis |
| B. | it lowers blood pressure |
| C. | circulating ANP has a short half-life |
| D. | ANP has the greatest affinity for the ANPR-B receptor of the glomerulus |
| E. | it is released when atrial muscle is stretched |
| Answer» E. it is released when atrial muscle is stretched | |
| 354. |
Regarding the structure of skeletal muscle, which statement is INCORRECT? |
| A. | thick filaments consist of myosin |
| B. | actin forms a double helix |
| C. | thin filaments include tropomyosin |
| D. | troponin-I inhibits interaction between actin and myosin |
| E. | T-system lies at Z-lines |
| Answer» F. | |
| 355. |
Regarding renal innervation: |
| A. | transplanted kidneys initially have reduced concentrating ability because of lack of innervation of the juxtaglomerular cells and therefore decreased renin secretion |
| B. | norepinephrine acts directly on receptors on the juxtaglomerular cells |
| C. | renal blood flow increases during exercise |
| D. | autoregulation of renal blood flow can be disrupted by angiotensin-II inhibitors when renal perfusion is low |
| Answer» E. | |
| 356. |
Regarding skeletal muscle, which statement is INCORRECT? |
| A. | resting membrane potential is about -90mV |
| B. | resting length is the length at which active tension in the muscle is maximal |
| C. | total glycogen stored is about 0.4kg |
| D. | energy source at rest is mainly glucose |
| E. | resting heat production is due to basal metabolic processes |
| Answer» E. resting heat production is due to basal metabolic processes | |
| 357. |
Regarding skeletal muscle: |
| A. | isotonic contraction does no work |
| B. | calcium is released from troponin during contraction |
| C. | the resting membrane potential is -70mV |
| D. | treppe occurs in skeletal muscle only |
| E. | white muscle has short twitch durations |
| Answer» F. | |
| 358. |
Which of the following does NOT stimulate erythropoietin secretion? |
| A. | cobalt salts |
| B. | thromboxanes |
| C. | androgens |
| D. | adenosine |
| E. | prostaglandins |
| Answer» C. androgens | |
| 359. |
Atrial natriuretic peptide decreases formation of all of the following EXCEPT: |
| A. | aldosterone |
| B. | cyclic GMP |
| C. | renin |
| D. | vasopressin |
| E. | angiotensin III |
| Answer» C. renin | |
| 360. |
Regarding sensory organ stimulation, which statement is INCORRECT? |
| A. | adaptation occurs over the temperature range 20-40 C |
| B. | pain is sensed by naked nerve endings |
| C. | pacinian corpuscles are rapidly adapting touch-pressure receptors |
| D. | naked nerve endings can detect all four cutaneous sensory modalities |
| E. | any given nerve ending can signal more than one sensory modality |
| Answer» F. | |
| 361. |
Regarding nerve fibres: |
| A. | type C myelinated fibres in the dorsal root conduct impulses concerning pain and temperature |
| B. | type A unmyelinated fibres conduct impulses concerning proprioception |
| C. | type A unmyelinated fibres conduct impulses concerning light touch |
| D. | type A unmyelinated fibres conduct impulses to muscle spindles |
| E. | type B myelinated fibres are located in preganglionic autonomic region |
| Answer» F. | |
| 362. |
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» F. | |
| 363. |
Which does not stimulate carotid bodies? |
| A. | carbon monoxide poisoning |
| B. | cyanide poisoning |
| C. | hypoxia |
| D. | hypercapnia |
| E. | increased H+ concentration |
| Answer» B. cyanide poisoning | |
| 364. |
With regards to cell membrane potential |
| A. | The Donnan effect relies on nondiffusible ions |
| B. | The exterior of the cell is negative with respect to the interior |
| C. | The membrane potential tends to push chloride out of the cell |
| D. | It can be derived by measuring the chloride concentration and using the Nernst equation |
| E. | Potassium leaks out against its concentration gradient |
| Answer» B. The exterior of the cell is negative with respect to the interior | |
| 365. |
In the autonomic nerve system, antagonism results in: |
| A. | constriction of the renal vasculature |
| B. | decreased velocity of conduction in the atrioventricular node |
| C. | decreased velocity of conduction in the HIS/Purkinje system |
| D. | decreased ventricular contractility |
| E. | increased insulin and glucagon secretion |
| Answer» F. | |
| 366. |
Regarding the osmolality of renal tubular fluid, is it? |
| A. | hypotonic in loop of Henle |
| B. | isotonic in proximal tubule |
| C. | hypertonic in distal tubule |
| D. | hypotonic in collecting duct |
| E. | hypotonic in proximal tubule |
| Answer» C. hypertonic in distal tubule | |
| 367. |
Regarding insulin: |
| A. | it increases amino acid uptake |
| B. | its absorption is not affected by the site of injection |
| C. | it causes reduced K+ uptake by cells |
| D. | it increases protein catabolism |
| E. | it is secreted by the cells in the islets of Langerhan |
| Answer» B. its absorption is not affected by the site of injection | |
| 368. |
Regarding the buffer system in the tubular fluid, which one is TRUE? |
| A. | the main buffer system is H2PO4 |
| B. | the main mechanism of H+ secretion in the proximal tubule is via proton pump |
| C. | dibasic phosphate buffer is most effective at proximal convoluted tubule |
| D. | the H+ secretion at proximal tubule is mediated Na/K/ATPase |
| E. | thick ascending limb of loop of Henle |
| Answer» E. thick ascending limb of loop of Henle | |
| 369. |
Osmolality of tubular fluid: |
| A. | isotonic in proximal tubule |
| B. | isotonic in loop of Henle |
| C. | hypertonic in ascending limb loop of Henle |
| D. | hypotonic in collecting duct |
| E. | hypotonic in proximal tubule |
| Answer» B. isotonic in loop of Henle | |
| 370. |
In diabetes insipidis: |
| A. | percentage of filtered water reabsorbed is increased compared to normal |
| B. | there is a net gain of water in excess of solute (L/day) |
| C. | urine volume (L/day) is decreased |
| D. | urine concentration (msom/L) is markedly reduced |
| E. | glomerular flow (ml/min) is increased |
| Answer» E. glomerular flow (ml/min) is increased | |
| 371. |
Which respiratory principle is INCORRECT? |
| A. | Fick s law states that the volume of gas per unit time that moves across a sheet of tissue is proportional to the area of the sheet, but inversely proportional to its thickness |
| B. | the Bohr effect is the effect of PCO2 on the O2 dissociation curve due to the action of PCO2 on H+ concentration |
| C. | Henry s law states that the amount of gas dissolved is proportional to the partial pressure of that gas |
| D. | the chloride shift is the diffusion of HCO3 - in to the cell, with the outward diffusion of Cl- ions to maintain electrical neutrality |
| E. | the Haldane effect is that deoxygenation of the blood increases its ability to carry CO2 |
| Answer» E. the Haldane effect is that deoxygenation of the blood increases its ability to carry CO2 | |
| 372. |
Regarding renal compensation in respiratory acidosis and alkalosis: |
| A. | the rate of HCO3 reabsorption is inversely proportional to the arterial PCO2 |
| B. | in respiratory acidosis, HCO3 reabsorption is reduced |
| C. | changes in plasma chloride concentration are proportional to CHO3 concentration |
| D. | in respiratory alkalosis, renal H+ secretion is increased |
| E. | HCO3 reabsorption depends upon the rate of H+ secretion by the renal tubular cells |
| Answer» F. | |
| 373. |
In the normal bladder, micturition: |
| A. | is initiated by the pelvic nerves |
| B. | is co-ordinated in the lumbar portion of the spinal cord |
| C. | is initiated at a volume of 600mls |
| D. | is significantly affected by sympathetic nerves |
| E. | is not facilitated at the level of the brain stem |
| Answer» B. is co-ordinated in the lumbar portion of the spinal cord | |
| 374. |
B nerve fibres transmit impulses of which modality? |
| A. | proprioception |
| B. | preganglionic autonomic |
| C. | temperature |
| D. | postganglionic sympathetic |
| E. | somatic motor |
| Answer» C. temperature | |
| 375. |
Regarding the bladder: |
| A. | the external urethral sphincter is made up of smooth muscle cells |
| B. | the internal urethral sphincter does not encircle the urethra |
| C. | pelvic nerves (S2-S4) supply the external sphincter |
| D. | when the bladder is stretched, tension is maintained |
| E. | relaxation of the internal urethral sphincter assists micturition |
| Answer» C. pelvic nerves (S2-S4) supply the external sphincter | |
| 376. |
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» E. digestive system | |
| 377. |
Which of the following decreases basal metabolic rate? |
| A. | recent ingestion of food |
| B. | stress |
| C. | increased thyroid hormones |
| D. | sleep |
| E. | lactation |
| Answer» E. lactation | |
| 378. |
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» E. are usually excreted in the urine | |
| 379. |
Regarding the autonomic nervous system: |
| A. | does not have a reflex arc like somatic nervous system |
| B. | has dopamine as the main transmitter |
| C. | has cholinergic division which increases activity of the intestinal musculature and increases gastric secretion |
| D. | neurotransmitter noradrenaline is metabolised by pseudocholinesterase |
| E. | is not involved with visceral sensation |
| Answer» D. neurotransmitter noradrenaline is metabolised by pseudocholinesterase | |
| 380. |
A-alpha nerve fibres transmit impulses of which modality? |
| A. | proprioception |
| B. | pain |
| C. | pressure |
| D. | touch |
| E. | motor to muscle spindles |
| Answer» B. pain | |
| 381. |
Regarding renal tubular function: |
| A. | Na+ is actively transported out of the thin portions of the loop of Henle |
| B. | Na+ -K+ ATPase pumps Na+ out of the renal tubule |
| C. | Cl- is transported only by co-transport |
| D. | glucose is reabsorbed mainly in the distal tubule |
| E. | penicillin is not actively secreted into tubular fluid |
| Answer» C. Cl- is transported only by co-transport | |
| 382. |
Regarding the anatomy of the kidney: |
| A. | the afferent arteriole is smaller than the efferent |
| B. | the kidney contains 1.3 million nephrons |
| C. | there are three layers separating the blood in the arteriole from the glomerular filtrate |
| D. | podocytes are contractile and regulate GFR |
| Answer» C. there are three layers separating the blood in the arteriole from the glomerular filtrate | |
| 383. |
Regarding smooth muscle, which statement is INCORRECT? |
| A. | multi-unit smooth muscle is present in the jejunum |
| B. | may exhibit pacemaker potentials |
| C. | mechanical response is much slower than striated muscle |
| D. | the membrane potential is unstable |
| E. | functions as a syncytium in viscera |
| Answer» B. may exhibit pacemaker potentials | |
| 384. |
Which of the following is NOT present in smooth muscle cells? |
| A. | actin |
| B. | myosin-II |
| C. | tropomyosin |
| D. | almodulin |
| E. | troponin |
| Answer» F. | |
| 385. |
Which pattern of laboratory findings in the tale below is most consistent with a diagnosis of diabetes insipidis? 24 Hr Urine Vol Ketones Glucose Protein |
| A. | 4.0 + 0 0 |
| B. | 6.2 2+ 4+ 0 |
| C. | 1.6 0 0 4+ |
| D. | 6.4 0 0 0 |
| E. | 5.0 0 0 3+ |
| Answer» E. 5.0 0 0 3+ | |
| 386. |
Which of the following is absent in smooth muscle? |
| A. | tropomysin |
| B. | actin |
| C. | myosin |
| D. | troponin |
| E. | mitochondria |
| Answer» E. mitochondria | |
| 387. |
Regarding smooth muscle: |
| A. | tropomyosin is absent |
| B. | the resting membrane potential is -90mV |
| C. | there is a highly developed sarcoplasmic reticulum |
| D. | there are no spike potentials |
| E. | dense bodies are attached to the cell membrane |
| Answer» F. | |
| 388. |
Regarding smooth muscle contractility, which statement is INCORRECT? |
| A. | increased by acetylcholine |
| B. | decreased by activation of phospholipase C |
| C. | increased by cold |
| D. | decreased by cAMP |
| E. | increased by stretch |
| Answer» C. increased by cold | |
| 389. |
The volume of the anatomical dead space is: |
| A. | 50mL |
| B. | 100mL |
| C. | 150mL |
| D. | 200ml |
| E. | 300ml |
| Answer» D. 200ml | |
| 390. |
With respect to blood flow: |
| A. | during laminar flow, blood moves at greater velocity adjacent to the vessel wall |
| B. | turbulent flow can occur in long straight vessels |
| C. | during turbulent flow, there is less resistance to flow |
| D. | the tendency for turbulent flow increases inversely with the velocity of blood flow |
| E. | turbulent flow does not normally occur in the aorta |
| Answer» C. during turbulent flow, there is less resistance to flow | |
| 391. |
Membrane potential: |
| A. | is only found in nervous tissue |
| B. | is not contributed to by the Na+ /K+ pump |
| C. | magnitude does not change from tissue to tissue |
| D. | is negative inside in relation to the outside |
| E. | is mainly caused by leaking Na+ / K+ channels |
| Answer» E. is mainly caused by leaking Na+ / K+ channels | |
| 392. |
Which of the following nerves is NOT of fibre type A? |
| A. | proprioception |
| B. | touch |
| C. | motor to muscle spindles |
| D. | somatic motor |
| E. | dorsal root pain and temperature |
| Answer» F. | |
| 393. |
The number of molecules in a mole is: |
| A. | 1 X 1026 |
| B. | 6 X 1026 |
| C. | 4 X 1026 |
| D. | 1 X 1023 |
| E. | 6 X 1023 |
| Answer» F. | |
| 394. |
Which nerves have the biggest diameter and faster conduction velocity? |
| A. | group A alpha |
| B. | group A beta |
| C. | group A gamma |
| D. | group A delta |
| E. | group C |
| Answer» B. group A beta | |
| 395. |
In the nervous control of the bladder which nerves do NOT play a role in micturition? |
| A. | sympathetic nerves from L2 in hypogastric nerve |
| B. | somatic motor neurons in pudendal nerve |
| C. | sensory neurons to S2/3 in pelvic nerves |
| D. | parasympathetic supply in pelvic nerves |
| E. | collecting duct |
| Answer» B. somatic motor neurons in pudendal nerve | |
| 396. |
Regarding nerve fibres, which statement is INCORRECT? |
| A. | resting membrane potential is about -90mV |
| B. | action potentials are generated at the initial segment in spinal motor neurons |
| C. | myelin produces up to 50 times faster conduction of impulses |
| D. | membrane is more permeable to potassium than sodium at rest |
| E. | sodium channels are highly concentrated at the nodes of ranvier |
| Answer» B. action potentials are generated at the initial segment in spinal motor neurons | |
| 397. |
Regarding conduction of nerve impulses, which statement is INCORRECT? |
| A. | it is an active, self-propagating process |
| B. | salutatory conduction occurs in unmyelinated neurons |
| C. | axons can conduct impulses in either direction |
| D. | conduction velocity is proportional to nerve fibre diameter |
| E. | current sink occurs in neuronal cell membrane ahead of impulse |
| Answer» C. axons can conduct impulses in either direction | |
| 398. |
Which of the following nerve fibre types is MOST sensitive to hypoxia? |
| A. | A-alpha |
| B. | A-beta |
| C. | A-delta |
| D. | B |
| E. | C |
| Answer» E. C | |
| 399. |
Comparing nerve fibre types which is FALSE? |
| A. | C fibres are most susceptible to local anaesthetic |
| B. | A fibres are least susceptible to local anaesthetic |
| C. | B fibres are found preganglionic autonomic |
| D. | A fibres transmit motor to muscle spindles |
| E. | some C fibres transmit postganglionic sympathetic impulses |
| Answer» E. some C fibres transmit postganglionic sympathetic impulses | |
| 400. |
Which of the following blood gas results is consistent with a three-week residence at 4000m altitude, after previously living at sea-level? pH HCO3 - (meq/L) pCO2 |
| A. | 7.40 24.1 40 |
| B. | 7.50 30.1 40 |
| C. | 6.96 5.0 23 |
| D. | 7.34 33.5 64 |
| E. | 7.48 18.7 26 |
| Answer» F. | |