It is known as Adenosine Triphosphate. This compound stores large amount of biological energy for a very short period of time. It serves as the energy currency of the cell. The plant metabolises the lipids, glycogen or carbohydrates to synthesize ATP depending upon the requirement. ATP has three constituents i.e. adenine base, a five-carbon sugar and three inorganic phosphate groups ATP is synthesized during respiration and photosynthesis.