Which type of proteins in plasma membranes actively transport ions against a concentration gradient?

Pump proteins are integral membrane proteins that play a crucial role in the active transport of ions across plasma membranes. They are responsible for moving substances from areas of lower concentration to areas of higher concentration, which is essential for maintaining concentration gradients essential for various cellular processes. This movement against the concentration gradient requires the input of energy, typically derived from the hydrolysis of ATP.

For example, the sodium-potassium pump, a well-known pump protein, actively transports sodium ions out of the cell and potassium ions into the cell, thereby establishing fundamental electrochemical gradients that are vital for functions such as nerve impulse transmission and muscle contraction.

In contrast, channel proteins facilitate the passive transport of ions and molecules across the membrane, allowing substances to move down their concentration gradients without the use of energy. Structural proteins provide structural support to the cell and do not partake in active transport. Receptor proteins are involved in signal transduction but do not actively transport ions across membranes.