Active Transport
Active transport is the process in which certain molecules are pumped across a membrane, against their concentration gradientCite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title. For this mechanism to work, and source of free energy must be supplied so the solute can move from an area of low concentration to an area of high concentrationCite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title. This source of energy can either come from the hydrolysis of an ATP molecule or an existing ion gradientCite error: Invalid <ref> tag; name cannot be a simple integer. Use a descriptive title.