Statement from Biology-Online.org; it states, "ATP to ADP - Energy Release. This is done by a simple process, in which one of the phosphate molecules is broken off, therefore reducing the ATP from 3 phosphates to 2, forming ADP"
In simpler words, ATP is a more powerful molecule containing 3 phosphates, while they will go into a cycle (I forgot the name), where phosphates are kicked out, therefore the ATP now has 2 phosphates, THUS TURNING INTO ADP. Since it had 2 phosphates, it is no longer classified as ATP, it is classified as ADP.
