Describe the adp molecule and its function within a cell.

Adenosine diphosphate (ADP) is formed by the removal of one phosphate from an ATP molecule by enzymes called ATPases. 
Adenosine diphosphate (ADP) is an organic molecule involved in the central part of the metabolism of the cell that generates energy. 
The interconversion of ATP and ADP takes place in various aspects of cellular metabolism. 
Another process in which ATP and ADP act together to supply energy is in the fast twitch of muscle cells. 
In mammals, ADP is involved in blood platelet activation, and is stored within platelets. 
A derivative of ADP is adenosine diphosphate ribose, in which the sugar ribose is linked to the final phosphate of ADP by an ester linkage.