Neurobiophysics – MCQs 50 Score: 0 Attempted: 0/50 Subscribe 1. The resting membrane potential of a typical neuron is approximately: (A) +70 mV (B) –70 mV (C) 0 mV (D) –55 mV 2. The action potential is primarily initiated by the opening of: (A) Potassium channels (B) Sodium channels (C) Calcium channels (D) Chloride channels 3. The threshold potential in most neurons is about: (A) –90 mV (B) –55 mV (C) +30 mV (D) –10 mV 4. Myelin sheaths increase conduction velocity by: (A) Continuous conduction (B) Saltatory conduction (C) Passive diffusion (D) Ion exchange only 5. The nodes of Ranvier are rich in: (A) Sodium channels (B) Potassium leak channels (C) Calcium pumps (D) Aquaporins 6. Which equation describes the equilibrium potential of an ion? (A) Gibbs equation (B) Nernst equation (C) Henderson-Hasselbalch equation (D) Michaelis-Menten equation 7. The Goldman-Hodgkin-Katz equation accounts for: (A) Multiple ion species across a membrane (B) Protein folding (C) Synaptic vesicle release (D) Neurotransmitter degradation 8. The depolarization phase of an action potential is due to: (A) Sodium influx (B) Potassium efflux (C) Calcium influx (D) Chloride influx 9. The repolarization phase is caused by: (A) Sodium influx (B) Potassium efflux (C) ATP hydrolysis (D) Chloride efflux 10. Hyperpolarization occurs when: (A) Potassium channels remain open longer (B) Sodium channels remain open (C) Calcium is released (D) ATP is depleted 11. The refractory period ensures: (A) Bidirectional propagation (B) Unidirectional propagation of action potentials (C) No signal conduction (D) Continuous neurotransmitter release 12. Synaptic vesicles are filled with neurotransmitters by: (A) Exocytosis (B) Proton gradient-driven transporters (C) Passive diffusion (D) Sodium-potassium pump 13. Neurotransmitter release is triggered by: (A) Sodium influx (B) Calcium influx (C) Potassium efflux (D) Chloride influx 14. The main excitatory neurotransmitter in the brain is: (A) GABA (B) Glycine (C) Glutamate (D) Serotonin 15. The main inhibitory neurotransmitter in the brain is: (A) Glutamate (B) GABA (C) Dopamine (D) Acetylcholine 16. Acetylcholine is degraded in the synaptic cleft by: (A) Monoamine oxidase (B) Acetylcholinesterase (C) Catechol-O-methyltransferase (D) ATPase 17. Ionotropic receptors are: (A) G-protein coupled (B) Ligand-gated ion channels (C) Enzyme-linked (D) Passive transporters 18. Metabotropic receptors act through: (A) Direct ion flow (B) G-protein signaling cascades (C) ATP hydrolysis only (D) Osmosis 19. The Hodgkin-Huxley model explains: (A) Ion channel gating in neurons (B) Neurotransmitter synthesis (C) Muscle contraction (D) DNA transcription 20. The speed of action potential propagation is higher in: (A) Small, unmyelinated axons (B) Large, myelinated axons (C) Dendrites (D) Synaptic terminals 21. EPSPs are caused by: (A) Influx of Na⁺ or Ca²⁺ (B) Efflux of K⁺ (C) Influx of Cl⁻ (D) ATP consumption 22. IPSPs are caused by: (A) Influx of Na⁺ (B) Influx of Cl⁻ or efflux of K⁺ (C) Influx of Ca²⁺ (D) ATP hydrolysis 23. Temporal summation occurs when: (A) Multiple inputs arrive simultaneously (B) Repeated inputs arrive rapidly at one synapse (C) Inhibitory and excitatory inputs cancel each other (D) Signals travel backward 24. Spatial summation occurs when: (A) One input fires multiple times (B) Several inputs from different synapses combine (C) Action potentials overlap (D) Vesicles fuse randomly 25. Voltage-gated calcium channels are concentrated at: (A) Soma (B) Dendrites (C) Presynaptic terminals (D) Axon hillock 26. The axon hillock is the site of: (A) Protein synthesis (B) Action potential initiation (C) Neurotransmitter packaging (D) Myelin formation 27. Microelectrode recordings are used to measure: (A) Ion channel structure (B) Electrical activity of neurons (C) DNA content (D) Protein folding 28. Patch-clamp technique is primarily used to study: (A) Whole cell metabolism (B) Single ion channel currents (C) Neurotransmitter synthesis (D) Action potential thresholds 29. The all-or-none principle refers to: (A) Synaptic vesicle release (B) Action potentials firing completely or not at all (C) Ion channel gating (D) Muscle contraction 30. Which ion is most important for maintaining resting potential? (A) Sodium (B) Potassium (C) Calcium (D) Chloride 31. The Na⁺/K⁺ ATPase pump moves: (A) 3 Na⁺ out, 2 K⁺ in (B) 2 Na⁺ out, 3 K⁺ in (C) 3 Na⁺ in, 2 K⁺ out (D) 2 Na⁺ in, 2 K⁺ out 32. Synaptic delay is typically: (A) <0.1 ms (B) 0.5–1.0 ms (C) 5–10 ms (D) 20 ms 33. Long-term potentiation (LTP) is important for: (A) Reflexes (B) Learning and memory (C) Resting potential (D) Protein degradation 34. NMDA receptors are unique because they require: (A) Only glutamate binding (B) Both glutamate and membrane depolarization (C) GABA binding (D) ATP hydrolysis 35. Axonal transport of vesicles is powered by: (A) Actin filaments (B) Microtubules and motor proteins (C) DNA helicases (D) Ion pumps 36. Retrograde axonal transport uses the motor protein: (A) Kinesin (B) Dynein (C) Myosin (D) Actin 37. Forward (anterograde) axonal transport uses: (A) Kinesin (B) Dynein (C) Myosin (D) Actin 38. Which imaging method measures brain activity via blood oxygenation? (A) CT scan (B) MRI (C) fMRI (D) X-ray 39. Electroencephalography (EEG) records: (A) Brain ion concentrations (B) Electrical activity from cortical neurons (C) Blood oxygen levels (D) Magnetic signals only 40. Magnetoencephalography (MEG) detects: (A) Chemical gradients (B) Magnetic fields from neuronal activity (C) Glucose metabolism (D) Calcium concentration 41. Synaptic plasticity refers to: (A) Structural rigidity of synapses (B) Changes in synaptic strength (C) ATP storage in neurons (D) Membrane thickness changes 42. Axon diameter affects conduction velocity because: (A) Smaller diameter speeds conduction (B) Larger diameter reduces resistance (C) Larger diameter increases resistance (D) Diameter has no effect 43. Inhibitory postsynaptic potentials often involve: (A) Sodium influx (B) Potassium efflux or chloride influx (C) Calcium influx (D) ATP hydrolysis 44. An excitatory postsynaptic potential moves the membrane potential: (A) Away from threshold (B) Toward threshold (C) To resting potential (D) To hyperpolarization 45. The refractory period ends when: (A) Sodium channels are inactivated (B) Potassium channels close and sodium channels reset (C) ATP levels rise (D) Chloride ions leave the cell 46. Conduction without myelin requires: (A) Continuous depolarization along the axon (B) Saltatory conduction (C) Ion pumps at nodes (D) Vesicle fusion 47. Synaptic vesicle fusion is mediated by: (A) Tubulin (B) SNARE proteins (C) Actin filaments (D) Kinesin 48. Miniature postsynaptic potentials result from: (A) Spontaneous vesicle release (B) Continuous sodium influx (C) ATP hydrolysis (D) Potassium efflux 49. The conduction velocity in myelinated axons can reach up to: (A) 10 m/s (B) 50 m/s (C) 120 m/s (D) 500 m/s 50. Voltage-gated sodium channels inactivate shortly after opening due to: (A) Potassium binding (B) Inactivation gate mechanism (C) ATP depletion (D) Calcium influx Molecular Biophysics – MCQsCellular Biophysics – MCQsMembrane Biophysics – MCQsNeurobiophysics – MCQsRadiation Biophysics – MCQsMedical Biophysics – MCQsComputational Biophysics – MCQsStructural Biophysics – MCQsBiophysical Chemistry – MCQsBioenergetics – MCQsBiomechanics – MCQsSystems Biophysics – MCQsBiomolecular Interactions – MCQsBiophysical Methods & Instrumentation – MCQsQuantum Biophysics – MCQsThermodynamics & Statistical Mechanics in Biology – MCQsBiophysics of Macromolecules – MCQs Electrophysiology – MCQsPhotobiophysics – MCQsNanobiophysics – MCQs