Structure of ATP

Adenosine Triphosphate (ATP) is composed if adenosine and three inorganic phosphates (Pi) groups.

We can see from the diagram on the left that energy stored in the molecule of ATP can only be released when the last phosphate is broken off by enzyme action.This results in the formation of ADP+Pi. The diagram also shows that energy is required to regenerate ATP from ADP+Pi, this is called phosphorylation. 

Production of ATP 

ATP is produced through the breakdown of glucose. As you may know from experiments glucose releases it's energy extremely quickly, especially when introduced to fire or an extreme heat. The body has to slow down this process, it does this by controlling it in separate stages through enzyme action.

Role of ATP

ATP is used in many different ways, a few would be: muscular contractions, protein synthesis, active transport and nerve impulses.
ATP also acts as a link between energy consuming reactions and energy releasing reactions, it provides a means by which chemical energy is able to be transferred from one type of reaction to the other in a living cell.

ATP has a rapid turnover. The body needs this to occur due to some cells needing up to two million molecules of ATP every second, this is why ATP has to be able to be regenerated. Also, the need for regeneration is evident when we look further in, the body only has a set amount of ATP in it's body (approximately 50g). If the body requires more ATP it will just regenerate more at that given time, this is why breathing rate increases at times of high activity. We will look further into this in Respiration.