What are the different types of active transport?

Active transport can be divided into two categories: primary active transport and secondary active transport.

Primary active transport directly uses adenosine triphosphate (e.g. ATP hydrolysis) to transport molecules through a cell membrane against the concentration gradient from a region of low concentration to high concentration. Common types of primary active transporters include endocytosis, exocytosis, sodium/potassium pumps and sodium-glucose transport protein.

Secondary active transport does not directly use ATP to transport molecules. Instead, it relies on an electrochemical gradient to move two different molecules across a membrane. One of the molecules, known as the driving molecule, will move down its concentration gradient, which causes the other molecule to move against its concentration gradient. Common types of secondary active transporters include antiport pumps (i.e. molecules travel in opposite directions) and symport pumps (i.e. molecules travel in the same direction).