Question

During repolarization:

a) the net charge inside the cell swings back in the positive direction
b) potassium ions move into the cell
c) potassium ions move out of the cell
d) the negatively charged potassium ions are repelled by the relatively positive charge inside the neuron caused by the sodium influx

Answer 1

During repolarization, potassium ions move out of the cell, leading to the membrane potential returning to its resting negative value.

Step-by-step explanation:

During repolarization, the correct answer is c) potassium ions move out of the cell. Repolarization is the phase during an action potential when the membrane potential returns towards the negative value of the resting membrane potential. As a result of potassium ion channels opening and allowing K+ to leave the cell, the inside of the cell becomes less positive because these positively charged potassium ions are moving out, taking positive charge with them. This movement directly contributes to the membrane potential shifting back towards its resting state of approximately -70 mV after the positive spike of depolarization caused by sodium ions entering the cell.