In previous modules you have looked at the role of the cell membrane, cell membrane channels, membrane pumps, and differences between the concentrations of sodium and potassium ions in the intracellular and extracellular fluid. Can you unify these ideas to explain how the cell membrane potential is generated?

The cell membrane prevents free movement of sodium and potassium ions between the intracellular and extracellular fluid. If sodium and potassium ions are going to move through the cell membrane they will move through gated channels. They can only get through the membrane when those channels are open.
There is a concentration gradient for sodium and potassium ions favouring the movement of potassium ions out of the cell in the movement of sodium ions into it. A small number of potassium channels are always open allowing potassium leakage out of the cell, and a small number of sodium channels open allowing potassium to enter it. Because there are more potassium ions leaving the cell than sodium ions entering it the interior of the cell develops a negative charge compared to the outside of the cell. This charge difference is maintained by the role of the sodium potassium ATPase pump which is continuously pumping 3 sodium ions back out of the cell and at the same time pumping 2 potassium ions back into it. Eventually the negative charge inside the cell opposes the exit of potassium ions. You can imagine that potassium ions are trying to move out of the cell down there concentration gradient but the negativity inside the cell is keeping them where they are. As result in equilibrium is reached and that is the resting membrane potential.