 ATP transports chemical energy within cells for metabolism . It is one of the end products of photophosphorylation , aerobic respiration , and fermentation , and is used by enzymes and structural proteins in many cellular processes , including biosynthetic reactions , motility , and cell division . One molecule of ATP contains three phosphate groups , and it is produced by a wide variety of enzymes , including ATP synthase , from adenosine diphosphate ( ADP ) or adenosine monophosphate ( AMP ) and various phosphate group donors . Substrate @-@ level phosphorylation , oxidative phosphorylation in cellular respiration , and photophosphorylation in photosynthesis are three major mechanisms of ATP biosynthesis . 
