All cell needs to be supplied with nutrients, electrolytes, water, and also all unwanted materials must be removed, and this can only be achieved by transport of substance in and out of the cell.
Active transport is the movement of a substance against the electrochemical gradient. For active transport to take place, energy is required. There are two major types of active transport which include:
Primary active transport which is a type of transport in which energy is released directly from the breakdown of ATP.
Secondary active transport is the transport of substance with the sodium ion. There are other special types of active transport, which include endocytosis, which is a transport mechanism in which macromolecules enter the cell, exocytosis is the process in which substance leaves the cell, and transcytosis is the process in which substance enter from one side of the cell.
Active transport is a cellular process of moving molecules across a cellular membrane (into or outside a cell) with the use of cellular energy. Active transport is further divided into primary active transport and secondary active transport. Primary active transport is carried out by the enzyme transmembrane ATPase with the use of ATP as the source of energy. An example of primary active transport in human physiology is the sodium/potassium pump that maintains membrane potential by pumping three ions of sodium out and two ions of potassium into the cell. Secondary active transport uses electrochemical potential as the source of energy to drive the movement of a molecule across a cellular membrane. In this form of active transport, both molecules being transported may move either in the same direction or opposite directions. When they move in the same direction, the process is known as symport, and when they move in opposite directions, it is known as antiport.