What is the role of ATP in active transport?

ATP has a crucial role in the active transport of molecules like proteins and lipids inside and out of the cell. The hydrolysis of ATP supplies the necessary energy for the active transport of molecules across a concentration gradient. Pumps that carry out primary active transport couple directly with ATP to generate their action. Small molecules are consistently passing through plasma membranes and active transport maintains the necessary concentration of molecules for homeostatic regulation. As one substance is moved into the cell, another is moved out. The sodium-potassium pump is an example of primary active transport. ATP is expended to pump potassium ions into the cell and sodium ions out. This results in an overall concentration and charge difference in the membrane.