ATP, ADP, and AMP differ in the number of phosphates and the amount of energy obtained by each compound.
ATP stands for adenosine triphosphate. ADP stands for adenosine diphosphate. AMP stands for adenosine monophosphate. Therefore, one difference between ATP, ADP, and AMP is the number of phosphates associated with each compound.
Another differences between the three molecules is the amount of energy stored within each molecule. Simply put, the more phosphates, the more energy stored. Thus, ATP has the most stored energy and AMP has the least amount of stored energy.
ATP is the main energy source for most cellular functions. ATP is created during cellular respiration in the mitochondria of eukaryotic cells. During cellular respiration, the sugar called glucose (C6H12O6) and oxygen gas (O2) is converted into carbon dioxide gas (CO2), water (H2O), and ATP.
The energy within ATP is released in order to perform everyday cellular functions as phosphates are removed.