What are the primary roles of the sodium-potassium pump in animal cells?
Answer
The primary role of the sodium-potassium pump (Na+/K+ -ATPase) is to maintain the electrochemical gradients across the plasma membrane of animal cells. It is a form of active transport, meaning it uses energy in the form of ATP to move ions against their concentration gradient.
For every single cycle of the pump, it moves ions in a specific ratio:
1. 3 Sodium (Na+) ions are pumped out of the cell. The concentration of Na+ is higher outside of the cell.
2. 2 Potassium (K+) ions are pumped into the cell. The concentration of K+ is higher inside the cell. Hence, the need for ATP to pump against concentration gradients.
Because three positive charges leave and only two enter, the inside of the cell becomes more negatively charged relative to the outside.