Final answer:
A protein pump in biology is a membrane protein that uses ATP to transport molecules against a concentration gradient. The sodium-potassium pump is an example that moves sodium and potassium ions across cell membranes, essential for nerve and muscle functions.
Step-by-step explanation:
A protein pump in biology refers to a membrane protein that utilizes energy from ATP to move ions or molecules across a cell membrane, typically against their concentration gradient in a process known as active transport. During active transport, a protein pump uses energy, in the form of ATP, to move molecules from an area of low concentration to an area of high concentration, akin to pumping air into a bicycle tire.
For example, the sodium-potassium pump (Na+/K+ pump) is a well-known protein pump that maintains the electrochemical gradient in cells by moving sodium and potassium ions across the membrane. This pump moves three sodium ions out of the cell and two potassium ions into the cell, with each cycle requiring the hydrolysis of one ATP molecule and resulting in the phosphorylation of the pump protein. This process changes the shape of the protein, enabling it to transport ions. The action of the sodium-potassium pump is vital for functions such as nerve impulse transmission and muscle contraction.
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