McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Biology .
Chapters
| 1. |
With reference to the action potential: |
| A. | decreasing the external Na+ concentration increases the size of the action potential |
| B. | decreasing the external K+ concentration decreases the resting membrane potential |
| C. | increasing the external Na+ concentration decreases the resting membrane potential |
| D. | decreasing the external K+ concentration has little effect on the resting membrane potential |
| E. | none of the above are true |
| Answer» E. none of the above are true | |
| 2. |
In the Erlanger and Gasser classification of nerve fibres: |
| A. | C fibres have the fastest conduction velocity |
| B. | Aγ fibres are responsible for touch and pressure |
| C. | C fibres are most susceptible to local anaesthetics |
| D. | Aα fibres have the fastest conduction velocity and the longest absolute refractory period |
| E. | A fibres are most susceptible to hypoxia |
| Answer» C. C fibres are most susceptible to local anaesthetics | |
| 3. |
Regarding neurotrophins: |
| A. | NGF and BDNF share the same receptor |
| B. | the structure of the β subunit of NGF resembles that of insulin |
| C. | CNTF is necessary for the growth and maintenance of sympathetic neurons |
| D. | disruption of GDNF by gene knockout causes a marked loss of cutaneous mechanoreceptors |
| E. | none of the above are true |
| Answer» B. the structure of the β subunit of NGF resembles that of insulin | |
| 4. |
Regarding cardiac muscle: |
| A. | cardiac muscle has high ATPase activity |
| B. | only the α MHC isoform is found in the atria |
| C. | resting membrane potential is about -70mV |
| D. | force of contraction is mediated by catecholamines acting via β1 -adrenergic receptors |
| E. | mutations of the human ether-a-go-go gene causes minks to shake their legs uncontrollably |
| Answer» D. force of contraction is mediated by catecholamines acting via β1 -adrenergic receptors | |
| 5. |
Which of the following does not decrease smooth muscle membrane potential? |
| A. | acetylcholine |
| B. | stretch |
| C. | cold |
| D. | noradrenaline |
| E. | parasympathetic stimulation |
| Answer» D. noradrenaline | |
| 6. |
In regard to plasma volume: |
| A. | it contributes to 10% of body weight |
| B. | can easily be measured by radioisotope chromium |
| C. | if the plasma volume is known, the blood volume can be calculated by multiplying100-HCT/100 |
| D. | measured by injecting Evans blue |
| E. | the average plasma volume is 500ml |
| Answer» D. measured by injecting Evans blue | |
| 7. |
Which of the following is FALSE? |
| A. | the ECF represents 20% of body weight |
| B. | the blood volume represents 8% of the body weight |
| C. | the 2/3 of the body water is in ICF |
| D. | 18% of the body weight is protein |
| E. | the transcellular fluids contribute to 5% of the body weight |
| Answer» E. the transcellular fluids contribute to 5% of the body weight | |
| 8. |
Which of the following is FALSE? |
| A. | diffusion depends on concentration gradient of the solutes |
| B. | osmotic pressure of a solution is inversely related to the volume of the solution |
| C. | when 5% dextrose is infused, it becomes hypotonic to the plasma in the body |
| D. | osmolality is defined as osmotically active particles in 1L of solution |
| E. | osmolality is defined as a number of osmotically active particles in 1kg of solvent |
| Answer» D. osmolality is defined as osmotically active particles in 1L of solution | |
| 9. |
Regarding cell membrane, which of the following is FALSE? |
| A. | the diameter of the cell membrane is about 7.5nm |
| B. | 50% of the cell membrane is made up of proteins |
| C. | the main lipids of the cell membrane are phospholipids |
| D. | the hydrophilic ends of the lipid molecules are faced towards the interior of the cell membrane |
| E. | the proteins in the cell membrane function as carriers, ion channels, enzymes and receptors |
| Answer» D. the hydrophilic ends of the lipid molecules are faced towards the interior of the cell membrane | |
| 10. |
Regarding mitochondria, which of the following is TRUE? |
| A. | 99% of mitochondrial proteins are products of mitochondrial DNA |
| B. | the outer membrane of the mitochondria is folded to form cristae |
| C. | the space between the outer and inner mitochondrial space is called matrix space |
| D. | it is the sperm which contributes to the formation of mitochondria in the zygote |
| E. | the synthesis of ATP in the mitochondria is triggered by diffusion of H+ from matrix to intracristal space |
| Answer» E. the synthesis of ATP in the mitochondria is triggered by diffusion of H+ from matrix to intracristal space | |
| 11. |
Which is FALSE? |
| A. | fast fibres have small number of mitochondria |
| B. | fast fibres are called white muscles |
| C. | the glycolic processes are more important in energy supply in fast fibres |
| D. | slow fibres are also called red fibres |
| E. | fast fibres have more extensive blood supply than slow fibres |
| Answer» E. fast fibres have more extensive blood supply than slow fibres | |
| 12. |
Smooth muscles differ from skeletal muscle by: |
| A. | not having actin/myosin |
| B. | not having striated appearance |
| C. | not using ATP for contraction |
| D. | not using Ca2+ for contraction |
| E. | not having sarcoplasmic reticulum |
| Answer» B. not having striated appearance | |
| 13. |
Which of the following is absent in smooth muscle? |
| A. | tropomysin |
| B. | actin |
| C. | myosin |
| D. | troponin |
| E. | mitochondria |
| Answer» D. troponin | |
| 14. |
The highest number of voltage gated Na+ channels are found in: |
| A. | initial segment of axon |
| B. | nodes of Ranvier |
| C. | cell body |
| D. | terminal buttons |
| E. | myeline sheath |
| Answer» A. initial segment of axon | |
| 15. |
Which of the following nerve fibres is most susceptible to hypoxia? |
| A. | group B |
| B. | group C |
| C. | group A – α |
| D. | dorsal root |
| E. | somatic motor |
| Answer» A. group B | |
| 16. |
Which of the following is most susceptible to pressure? |
| A. | group A – motor |
| B. | group C |
| C. | group B |
| D. | pre ganglionic-autonomic |
| E. | muscle spindle fibres |
| Answer» A. group A – motor | |
| 17. |
Regarding nerve action potential, which is TRUE? |
| A. | normal resting membrane potential is -40mV |
| B. | initial rapid depolarisation is due to rapid influx of Ca2+ via fast channels |
| C. | during depolarisation, Na+ permeality is greater than K+ permeality |
| D. | hyperpolarisation is due to continuous opening of Na+ channels |
| E. | plateau is formed by slow Ca2+ channels |
| Answer» C. during depolarisation, Na+ permeality is greater than K+ permeality | |
| 18. |
Which is FALSE regarding secondary active transport? |
| A. | it always transports substances in one direction |
| B. | energy required is obtained by Na+ /K+ ATPase pump |
| C. | a good example is Na+ / glucose co-transport |
| D. | Na+ / Ca2+ antiport is an example of secondary active transport |
| E. | secondary active transport occurs in renal tubules |
| Answer» A. it always transports substances in one direction | |
| 19. |
Which is TRUE? |
| A. | steroids act via cAMP |
| B. | insulin acts via IP3 |
| C. | EGF+ erythropoietin act via cAMP |
| D. | thyroid hormones act via G proteins |
| E. | retinoic acid act via intracellular receptor → transcription of genes |
| Answer» E. retinoic acid act via intracellular receptor → transcription of genes | |
| 20. |
Na+ / K+ ATPase pump – which is FALSE? |
| A. | it is electrogenic in nature |
| B. | it is important in maintaining cell volume |
| C. | plays a major role in secondary active transport |
| D. | it is the main factor which determine the resting membrane potential |
| E. | it is an example of primary active transport |
| Answer» D. it is the main factor which determine the resting membrane potential | |
| 21. |
Regarding serotonin: |
| A. | the highest concentration is in the brain |
| B. | formed by hydroxylation and decarboxylation of tyrosine |
| C. | catabolised by COMT |
| D. | some receptors are ion channels |
| E. | mediates smooth muscle relaxation |
| Answer» D. some receptors are ion channels | |
| 22. |
GABA: |
| A. | decreases Cl- conductance |
| B. | is broken down by glutamate decarboxylase (GA????) |
| C. | there are five receptor subtypes |
| D. | benzodiazepines bind to the β subunit of the GABA receptor |
| E. | is involved in 20% of CNS synapses |
| Answer» E. is involved in 20% of CNS synapses | |
| 23. |
Which is NOT present in high concentrations, at the active zone of synapses? |
| A. | syntaxin |
| B. | catecholamine vesicles |
| C. | neuropeptide vesicles |
| D. | synaptobrevin |
| E. | calcium channels |
| Answer» C. neuropeptide vesicles | |
| 24. |
Which is not a ligand-gated ion channel? |
| A. | nicotinic receptor |
| B. | GABAA receptor |
| C. | glycine receptor |
| D. | NMDA receptor |
| E. | 5-HT1 receptor |
| Answer» E. 5-HT1 receptor | |
| 25. |
Which drug is NOT involved in facilitating Cl- conductance? |
| A. | benzodiazepines |
| B. | progesterone |
| C. | oestrogen |
| D. | barbiturates |
| E. | alcohol |
| Answer» C. oestrogen | |
| 26. |
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» E. white muscle has short twitch durations | |
| 27. |
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» E. ↑cAMP leads to ↑ force of contraction | |
| 28. |
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» E. dense bodies are attached to the cell membrane | |
| 29. |
Regarding synapses: |
| A. | large vesicles contain ACh |
| B. | Na+ influx triggers fusion / exocytosis of vesicles |
| C. | I PSP can be produced by closing K channels |
| D. | the synaptic cleft is 100-150nm |
| E. | neurotransmitters migrate down the axon by fast axoplasmic transport |
| Answer» E. neurotransmitters migrate down the axon by fast axoplasmic transport | |
| 30. |
Regarding acetylcholine: |
| A. | it is oxidised to choline and acetate by acetylcholinesterase |
| B. | nicotinic receptors are blocked by atropine |
| C. | it is the main excitatory transmitter in the spinal cord |
| D. | it is secreted by the adrenal medulla |
| E. | tetanus blocks its release at the NMJ |
| Answer» E. tetanus blocks its release at the NMJ | |
| 31. |
Regarding synaptic structure / function: |
| A. | small clear vesicles in the presynaptic tunnel contain catecholamines |
| B. | tetanus toxin causes spastic paralysis by blocking release of ACh at NMJ |
| C. | chemical mediators located in ???? of presynaptic fibres contain one-way conduction of impulses |
| D. | the EPSP is an all-or-none response |
| E. | An I-PSP can be produced by localised increase in membrane permeability to Cl- |
| Answer» C. chemical mediators located in ???? of presynaptic fibres contain one-way conduction of impulses | |
| 32. |
Transmitters – all are true EXCEPT: |
| A. | angiotensin II is a neurotransmitter of the polypeptidillars |
| B. | glutamate is an inhibitory amino acid |
| C. | glucagons is found in hypothalamus and retina |
| D. | vasopressin is found in posterior pituitary, medulla, spinal cord |
| E. | serotonin is an amine |
| Answer» B. glutamate is an inhibitory amino acid | |
| 33. |
Neurotransmitters: |
| A. | atropine blocks effect of acetylcholine at ???? receptor |
| B. | reaction between active acetate and choline is catalysed by acetylcholinesterase |
| C. | nicotinic cholinergic receptors are serpentine receptors |
| D. | the rate limiting step in synthesis of NOVA is ?????(concussion) of tyrosine to dopa |
| E. | MAOA is found in nerve endings and platelets |
| Answer» D. the rate limiting step in synthesis of NOVA is ?????(concussion) of tyrosine to dopa | |
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