Answer: ATP (adenosine triphosphate) is considered as the energy currency of the cell. This means that it is used as one of the most important energy source for driving metabolic functions (like muscle contraction) within the cell.
ATP stores large amount of energy within its phosphoanhydride bond (present between two phosphate). Whenever a cell requires energy, ATP undergoes hydrolysis and gets converted into ADP (adenosine diphosphate) and inorganic phosphate and the large amount of stored energy is released that is further utilized by the cell for driving its functions.