AP BIOLOGY

Detailed explanation-1: -The sodium-potassium pump goes through cycles of shape changes to help maintain a negative membrane potential. In each cycle, three sodium ions exit the cell, while two potassium ions enter the cell. These ions travel against the concentration gradient, so this process requires ATP.

Detailed explanation-2: -The sodium-potassium pump moves three sodium ions out of the cell for every two potassium ions it moves into the cell continuously. It, therefore, maintains the large potassium ion gradient across the membrane, which in turn provided the basis for resting membrane potential.

Detailed explanation-3: -The sodium-potassium pump transports sodium out of and potassium into the cell in a repeating cycle of conformational (shape) changes. In each cycle, three sodium ions exit the cell, while two potassium ions enter.

Detailed explanation-4: -Sodium-potassium exchange pump Three intracellular sodium ions will be exchanged for every two extracellular potassium ions. At normal resting membrane potential, the sodium ions are ejected as fast as they can enter. The exchange pump then balances the passive forces of diffusion.