Question

Choose the correct feature for the events with respect to a neuron: Event Feature

A.	Repolarization	I.	Electrochemical equilibrium at -70 mV
B.	Resting potential	II.	Influx of ${\mathrm{Na}}^{+}$ ions
C.	Hyperpolarization	III.	Voltage gated $K^{+}$ channel opens
D.	Depolarization	IV.	Membrane potential going beyond -70 mV

• A. A-III, B-IV, C-I, D-II
• B. A-II, B-IV, C-I, D-III
• C. A-II, B-I, C-IV, D-III
• D. A-III, B-I, C-IV, D-II

Answer 1

The correct option is D A-III, B-I, C-IV, D-II

Event Feature

Resting potential	Electrochemical equilibrium at -70 mV
Depolarization	Influx of ${\mathrm{Na}}^{+}$ ions
Repolarization	Voltage gated $K^{+}$ channel opens
Hyperpolarization	Membrane potential going beyond -70 mV

Resting potential of -70 mV is same for all the neurons.

Depolarization happens when the neuron gets the stimulus. This results in the opening of ligand gated sodium channels causing the influx of sodium ions.

Hence, the membrane potential is altered due to movement in ions across the membrane.

Repolarization happens when voltage gated potassium channels are opened as the membrane potential increases from -55 mV.

Potassium ions from the inside move out of the cell making the cytoplasmic side more negative.

Hyperpolarization is the overshoot of membrane potential beyond -70 mV which is brought back to normal by slight depolarization.