The two major types are and Secondary Active Transport . They are distinguished by how they obtain the energy needed to move the solute. Type 1: Primary Active Transport Definition: The transport of molecules against their concentration gradient using energy directly from the hydrolysis of ATP (or another energy source like light).

Active transport is the movement of molecules or ions across a cell membrane against their concentration gradient (from low to high concentration). This process requires energy (usually ATP) because it is moving substances away from equilibrium.

| Subtype | Direction of Coupled Movement | Example | | :--- | :--- | :--- | | | Both molecules move in the same direction across the membrane. | Sodium-glucose linked transporter (SGLT) in kidney/intestine. | | Antiport (Exchange) | The two molecules move in opposite directions across the membrane. | Sodium-Calcium exchanger (NCX) in cardiac muscle. |

Adenosine Triphosphate (ATP). The pump itself is an ATPase enzyme that breaks ATP into ADP + Pi, releasing energy.