<Tr> <Td_colspan="2"> Infobox references </Td> </Tr> <Tr> <Td> </Td> <Td> </Td> </Tr> <P> Adenosine diphosphate (ADP), also known as adenosine pyrophosphate (APP), is an important organic compound in metabolism and is essential to the flow of energy in living cells . ADP consists of three important structural components: a sugar backbone attached to adenine and two phosphate groups bonded to the 5 carbon atom of ribose . The diphosphate group of ADP is attachted to the 5' carbon of the sugar backbone, while the adenosine attaches to the 1' carbon . </P> <P> ADP can be interconverted to adenosine triphosphate (ATP) and adenosine monophosphate (AMP). ATP contains one more phosphate group than does ADP . AMP contains one fewer phosphate group . Energy transfer used by all living things is a result of dephosphorylation of ATP by enzymes known as ATPases . The cleavage of a phosphate group from ATP results in the coupling of energy to metabolic reactions and a by - product of ADP . Being the "molecular unit of currency", ATP is continually being reformed from lower - energy species ADP and AMP . The biosynthesis of ATP is achieved throughout processes such as substrate - level phosphorylation, oxidative phosphorylation, and photophosphorylation, all of which facilitating the addition of a phosphate group to ADP . </P>

What role does adp/atp play in living cells