The sodium-potassium pump is a vital protein found in the cell membrane of many cells. It helps maintain the balance of sodium and potassium ions inside and outside the cell. By actively transporting three sodium ions out of the cell and two potassium ions into the cell, it creates an electrochemical gradient essential for various cellular functions. This pump uses energy from ATP to function, making it an example of active transport. The proper functioning of the sodium-potassium pump is crucial for processes like nerve impulse transmission and muscle contraction, as it helps regulate cell volume and electrical activity.