What is the primary function of the sodium pump in cells?

The primary function of the sodium pump, also known as the sodium-potassium ATPase, is to transport sodium ions out of the cell while simultaneously bringing potassium ions into the cell. This active transport mechanism is vital for maintaining the electrochemical gradient across the cell membrane, which is essential for various cellular processes, including nerve impulse transmission and muscle contraction. By regulating the concentration of sodium and potassium ions, the sodium pump helps to establish resting membrane potential and ensures that cells can respond appropriately to stimuli. This process requires energy in the form of ATP, as it moves ions against their concentration gradients.

In the context of the other options, while the movement of potassium ions is a function of the pump (as it simultaneously moves them into the cell), the primary role centers around the export of sodium ions. The regulation of pH levels and enhancement of protein synthesis are not direct roles of the sodium pump; instead, those processes are regulated by different cellular mechanisms and structures.