ATP or adenosine triphosphate is a nucleoside phosphate containing a purine base adenine, a sugar ribose and three phosphate groups. It can be produced inside the cells of any organisms through respiration. ATP transports the chemical energy in the cells to perform the metabolic functions. ATP is often called as the "molecular unit of currency" since it can both hold and release energy depending on the need of every cells.
ATP synthase is an enzyme responsible for the production of ATP in the cells. Without them, cellular metabolism will not push through since the primary currency of energy source of cells is the ATP. ATP synthase uses a hydrogen ion gradient to drive the production of ATP molecules.
Oxidative phosphorylation in mitochondria is catalysed by a multicomponent enzymatic complex called ATPase (ATP synthetase) or a coupling factor. This ATPase has a stalk and a headpiece located completely across the inner mitochondrial membrane. The headpiece extends towards the matrix whereas the stalk is embedded in the inner mitochondrial membrane and extends outwardly towards the space between the inner and outer membrane. The ATPase has been isolated in its pure form, which consists of two coupling factors- CFo and CF1.The ATP is formed at or in the headpiece of ATPase complex within the matrix of mitochondria and then transported to cytosol in exchange for incoming ADP.