Why is ATP used as an energy store in cells?

ATP is an unstable molecule therefore it releases the energy stored readily and quickly, this is essential for metabolic processes in the cell such as active transport and protein synhesis. As well as being unstable ATP is a very small moleule this means the energy is in manageable packages and can be releaed as required, this reduces waste. When the energy from ATP is used it is converted to ADP and Pi (inorganic phosphate), this is a revrsible reaction meanng ATP can be recyced depending on demand.