Question

why does repolarization occur? multiple choice potassium ions continue to diffuse out of the cell after the inactivation gates of the voltage - gated sodium ion channels begin to close. the extra efflux of potassium ions causes the membrane potential to become slightly more positive than the resting value. the increased potassium ion permeability lasts slightly longer than the time required to bring the membrane potential back to its resting level. more sodium ions diffuse into the cell than potassium ions diffuse out of it. the inactivation gates of the voltage - gated sodium ion channels begin to open, and the diffusion of sodium ions decreases.

Explanation:

Repolarization occurs when the inactivation gates of voltage - gated sodium ion channels close and potassium ions continue to diffuse out of the cell. This restores the negative resting membrane potential. The extra efflux of potassium ions can cause a brief hyperpolarization. Also, the increased potassium ion permeability lasts slightly longer than needed to return to the resting potential. More sodium ions diffusing into the cell would depolarize, not repolarize. And when inactivation gates of sodium channels open, sodium diffusion would increase, not decrease.

Answer:

Potassium ions continue to diffuse out of the cell after the inactivation gates of the voltage - gated sodium ion channels begin to close.