Atp is an abbreviation for adenosine triphosphate, a complex molecule that contains the nucleoside adenosine and a tail consisting of three phosphates. it is the energy currency of the cell. which statements regarding the atp-adp cycle are true? atp synthesis takes place in the mitochondria of eukaryotic cells. atp is regenerated from adp through the process of phosphorylation. energy is stored in the covalent bonds between phosphates, with the greatest amount of energy in the bond between the second and third phosphate groups. most of the readily available energy stored in atp is stored during the manufacture of adenosine. the ribose sugar in the model above is the direct product of photosynthesis.