Question

Which of the following correctly describes the resting potential of a neuron?

a. There are more positively charged ions inside the cell than there are outside the cell, making the cytoplasm slightly positive by comparison.

b. There are more positively charged ions outside the cell than there are inside the cell, making the cytoplasm slightly negative by comparison.

c. There are more positively charged ions inside the cell than there are outside the cell, making the cytoplasm slightly negative by comparison.

d. There are more positively charged ions outside the cell than there are inside the cell, making the cytoplasm slightly positive by comparison.

Answer 1

The resting potential of a neuron is approximately 70 millivolts more negative than the outside of the cell. This is caused by differences in ion concentrations and selective permeability. Sodium-potassium pumps maintain these ion concentrations.

Step-by-step explanation:

A neuron at rest is negatively charged: the inside of a cell is approximately 70 millivolts more negative than the outside (-70 mV). This voltage is called the resting membrane potential; it is caused by differences in the concentrations of ions inside and outside the cell and the selective permeability created by ion channels. Sodium-potassium pumps in the membrane produce the different ion concentrations inside and outside of the cell by bringing in two K+ ions and removing three Na+ ions.