Final answer:
The sodium-potassium pump moves sodium ions out of the cell and potassium ions into the cell, using energy from ATP. It follows a cycle where three sodium ions bind to the carrier protein inside the cell, are released outside the cell, and two potassium ions bind and are transported into the cell.
Step-by-step explanation:
The sodium-potassium pump is a protein found in cell membranes that moves sodium ions (Na+) out of the cell and potassium ions (K^+) into the cell. During one cycle of the pump, three sodium ions bind to the carrier protein inside the cell. The carrier protein uses energy from ATP to change shape and releases the sodium ions outside the cell. At that point, two potassium ions from outside the cell bind to the carrier protein and are transported into the cell. This process is then repeated.