Each pump is custom-built for one type of molecule or ion. A calcium pump refuses to transport sodium. A glucose active transporter ignores fructose. This specificity prevents metabolic chaos.
-ATPase) constantly works against steep gradients. It pumps sodium ions out of the cell and potassium ions into the cell. Both ions move from areas of low concentration to areas of already high concentration. This establishes the electrical voltage necessary for muscle contractions and nerve signals. 2. Requirement of Metabolic Energy (ATP)