How does ATP release energy?

ATP releases energy primarily through the hydrolysis of the bond between the second and third phosphate groups. This bond, which is known as a high-energy bond, is relatively unstable due to the negative charges on the phosphate groups that repel each other. When ATP is broken down into ADP (adenosine diphosphate) and an inorganic phosphate (Pi) by the enzyme ATPase, this bond is cleaved. The breaking of this bond releases energy that can then be used to perform various cellular functions, such as muscle contraction, active transport, and biosynthesis.

In this process, ATPase plays a crucial role by facilitating the reaction that leads to the release of energy. The energy that is released during the hydrolysis of ATP is what fuels many biochemical reactions in living organisms. Thus, the reasoning for the selected answer highlights the importance of the instability and energy of the bond being broken, as this interaction is central to ATP's function as an energy currency in the cell.