The movement of molecules which occurs from region of low to high concentration across the cell membrane is known as active transport.
Cellular energy is utilised to achieve this movement.
Two types of active transport:
Primary active transport: In this type of transport, the energy is utilised due to breakdown of the ATP (Adenosine triphosphate) to transport the molecules across the membrane against a concentration gradient.
Thus, all the groups of ATP powered pumps contain either one or more binding sites for the ATP molecules, which is located on the cytosolic face of the membrane.
Sodium-potassium pump, is the the most important pump found in the animal cells for primary active transport.
Secondary active transport: Secondary active transport is a type of active transport that uses electrochemical energy.
It also takes place across the biological membrane in which a transporter protein couples with the movement of an electrochemical ion (mainly Na+ or H+) down its electrochemical gradient to upward movement of another molecule or an ion against a concentration.