Adenosine Diphosphate

Adenosine Diphosphate, also known as ADP, has only one real function, to join with another phosphate group to make Adenosine Triphosphate. It makes four ATP in glycolysis, but two are used up. It also makes two more ATP in the Citric Acid Cycle, and makes 32 more ATP in the Electron Transport Chain, for a total of 36 Net ATP.

The chemical makeup of ADP is an adenine base, ribose, and two phosphate groups. The adenine and ribose mix to form adenosine, and the two phosphate groups make diphosphate.