The answer is ATP (adenosine tri phosphate).This is the main source of energy that is used by the cells of the body is. All the metabolic processes requires energy to function properly. The cell break the bond and converts adenosine triphosphate into adenosine di phosphate (ADP) through the process of hydrolysis. One the ATP is utilized by the cells it is recycled by cellular respiration ,where it needs phosphate group to store energy.