What Are Primary and Secondary Active Transport?

Primary and secondary active transport refer to the movement of molecules and cell components within cells and throughout the body. Primary and secondary active transport require energy to work and are both important for delivering living creatures with the nutrients and energy they need to move and carry out basic life functions.

Primary active transport, like secondary transport, starts with energy. This process begins with the movement of tiny cell molecules upward and across concentration gradients. The movement of these molecules creates friction and heat, which in turn generates potential energy across membrane surfaces. The energy produced by this movement is then stored in intracellular chemical bonds, which lie embedded in concentration gradients. This energy lies dormant until ATP arrives; the interaction of ATP with the transported energy results in the release of energy, which assumes the shape of protein as it moves across the membrane surface. Then, energy transfers from ATP to the transport protein.

Secondary active transport involves the interaction between two molecules. The process begins with the movement of a molecule down a concentration gradient, which reacts with a transport protein to move a second molecule across its concentration gradient. Then, an exchange of energy takes place between the two molecules, completing the process.