When a neuron is at rest before an action potential,
A) the membrane is depolarized.
B) membrane ion channels are open.
C) potassium is diffusing out of the cell.
D) the inside of the neuron is negative relative to just outside the neuron.

Question

Quizplus · Accepted Answer

When a neuron is at rest before an action potential, the inside of the neuron is negative relative to just outside the neuron. This is due to a higher concentration of positively charged ions outside the membrane and a higher concentration of negatively charged ions inside the membrane. This balance of charges creates a resting membrane potential, which is typically around -70 millivolts. At rest, membrane ion channels are closed, but there is a steady diffusion of potassium ions out of the cell, which helps to maintain the resting potential.

When a Neuron Is at Rest Before an Action Potential