Adenosine Triphosphate (ATP)
Adenosine Triphosphate (ATP): A common form in which energy is stored in living systems; consists of a nucleotide (with ribose sugar) with three phosphate groups. The energy coin of the cell.
Adenosine Diphosphate (ADP): Lower energy form of ATP, having two (instead of the three in ATP) phosphhate groups attached to the adenine base and ribose sugar.
Adenosine Diphospahate (ADP): ADP is formed when ATP is broken down within the bodies cell furnace, (the mitochondria). This provides energy for muscular contraction.