Which of the following is NOT a contributor to membrane potential?

Membrane potential is primarily influenced by the distribution of ions across the membrane and the permeability of the membrane to these ions. The key contributors include ion channels that allow specific ions to move in and out of the cell and active transport mechanisms that maintain the concentration gradients of these ions.

Na leak channels and K leak channels are both integral to the establishment of the resting membrane potential. They allow sodium and potassium ions to move passively across the membrane according to their concentration gradients. The Na/K pump actively transports sodium ions out of the cell and potassium ions into the cell, crucial for maintaining the resting membrane potential and the overall ionic balance.

Water movement, while essential for many cellular functions, does not directly influence the formation of membrane potential. Membrane potential is specifically tied to the charge and concentration of ions; therefore, the movement of water (H2O) alone does not contribute to the electrical gradient established across the membrane. The osmotic effects of water can indirectly affect the cell’s volume and turgor pressure, but they don’t impact the electrical aspects of membrane potential.