where does the phosphate come from in atp
Adenosine triphosphate In terms of its structure, ATP consists of an adenine attached by the 9-nitrogen atom to the 1′ carbon atom of a sugar (ribose), which in turn is attached at the 5′ carbon atom of the sugar to a triphosphate group. In its many reactions related to metabolism, the adenine and sugar groups remain unchanged, but the triphosphate is converted to di- and monophosphate, giving respectively the derivatives ADP and AMP. The three phosphoryl groups are referred to as the alpha (α), beta (β), and, for the terminal phosphate, gamma (γ).
Bioenergetic systems Creatine phosphate (CP), like ATP, is stored in muscle cells. When it is broken down, a large amount of energy is released. The energy released is coupled to the energy requirement necessary for the resynthesis of ATP.