All cells contain ion pumps that use the energy of atp hydrolysis to pump ions across the plasma membrane. These pumps create an electrochemical gradient across the plasma membrane that is used to power other processes at the plasma membrane
Facilitated diffusion pumps polar and charged molecules, such as carbohydrates, amino acids, nucleosides, and ions, cross the plasma membrane.
As sodium ion concentrations build outside the plasma membrane because of the action of the primary active transport process, an electrochemical gradient is created
