What are the types of active transport?

Active transport is a term used in cellular biology to describe the movement of molecules across cell membranes against the concentration gradient. This type of movement from an area of lower concentration to an area of higher concentration can only be achieved with the help of some type of cellular energy.

Active transport mechanisms can be divided into two types depending on the source of energy used – primary active transport and secondary active transport.  

Primary active transport – Primary active transport uses energy that is derived directly from the breakdown of adenosine triphosphate (ATP).   

Secondary active transport – Secondary active transport also use energy derived from ATP, however the energy is not directly used to transport the molecule across the membrane. It uses the electrochemical gradient generated by the primary active transport process to move the target molecule against the gradient. Secondary active transport is also known as cotransport.