Adenosine triphosphate (ATP) is a short-lived molecule that briefly stores energy gained from exergonic reactions. ATP consists of a double carbon-nitrogen ring called adenine; the five-carbon sugar, ribose; and a chain of three phosphate groups. Most of the energy transfers involving ATP involve breaking a bond between the third phosphate group and the rest of the molecule. The bond is frequently referred to as a high-energy bond. When that bond is broken, an abundance of energy is released.