Adenosine triphosphate, or ATP, is a molecule that stores all the energy required for cells to function. It is present in the nucleoplasm and cytoplasm of every cell. All of the energy needed to perform physiological operations is directly obtained from ATP.
An ATP molecule has three components: a sugar molecule center called ribose, a base of linked nitrogen and carbon atoms called adenine and a string of phosphate groups.
Energy is released from ATP molecules by a reaction that eliminates one of the phosphate-oxygen groups, leaving adenosine diphosphate, or ADP, behind. After an ATP molecule has been converted to ADP, the energy is spent.