Active transport

Active transport is the movement of the molecules against their concentration gradient using Adenosine triphosphate (ATP) as a source of energy. There are two types of active transport; primary active transport and secondary active transport. Primary active transport is the movement of two different molecules using ATP. It is usually called ATPase; an example of this type of this is Na⁺/K⁺ ATPase. Secondary active transport is the co movement of one molecule by the other; the potential energy produced by the movement of molecule down its concentration gradient is used to drive the movement of another molecule against its concentration gradient. The two molecules can be transported in the same direction (symport) or in different direction (antiport). An example of secondary active transport is Na⁺ - Ca²⁺ exchanger (antiport).

Active transport is very important as it allows the cell to uptake essential molecules such as glucose even when they are at low concentrations outside the cell.