Question

When voltage-gated K+ channels of a resting neuron open,

A) K+ leaves the neuron.
B) the neuron depolarizes.
C) K+ leaves the neuron and the neuron depolarizes.
D) K+ enters the neuron and the neuron depolarizes.
E) K+ enters the neuron.

Answer 1

When voltage-gated K+ channels of a resting neuron open, K+ ions leave the neuron, leading to repolarization of the neuron where the membrane potential becomes more negative, moving back towards the resting potential.

Step-by-step explanation:

When voltage-gated K+ channels of a resting neuron open, option A is correct: K+ leaves the neuron. This efflux of potassium ions is an essential part of action potential repolarization. Unlike depolarization, which involves the influx of Na+ ions, repolarization occurs when the membrane potential returns towards the resting level due to the exiting K+ ions. The neuron does not depolarize in this phase; on the contrary, the neuron's membrane potential becomes more negative during repolarization, moving back towards the resting potential. This process is different from depolarization where the membrane potential decreases and becomes less negative inside compared to outside.