Which of the following best describes the way atp works as a high energy compound? a) atp + energy -> adp. b) adp + energy -> atp. c) adp + p + energy -> atp. nad + atp + energy -> adp + nadh

ATP hydrolysis is the catabolic reaction process by which chemical energy that has been stored in the high-energy phosphoanhydride bonds in adenosine triphosphate (ATP) is released by splitting these bonds, for example in muscles, by producing work in the form of mechanical energy. The product is adenosine diphosphate(ADP) and an inorganic phosphate, orthophosphate (Pi). ADP can be further hydrolyzed to give energy, adenosine monophosphate (AMP), and another orthophosphate (Pi).[1] ATP hydrolysis is the final link between the energy derived from food or sunlight and useful work such as muscle contraction, the establishment of electrochemical gradients across membranes, and biosynthetic processes necessary to maintain life.

The description and typical textbook labeling anhydridic bonds as "high energy . . bonds" can be very misleading to students. These bonds are in fact relatively weak. They do involve high energy electrons but the bonds themselves are quite easy to break. As noted below, energy is released by the hydrolysis of ATP when these weak bonds are broken – requiring a small input of energy, followed by the formation of new bonds and the release of a larger amount of energy as the total energy of the system is lowered and becomes more stable.