Final answer:
The hydrolysis of ADP to AMP releases less energy compared to the hydrolysis of ATP to AMP because the bond between the remaining phosphates in ADP is lower in energy. Therefore, less energy would be released in the hydrolysis of ADP to AMP.
Step-by-step explanation:
The hydrolysis of ADP (adenosine diphosphate) to AMP (adenosine monophosphate) releases less energy compared to the hydrolysis of ATP to AMP. The bonds between the phosphate groups in ATP contain high energy, and when they are broken, as when ATP is hydrolyzed to ADP and a phosphate group (Pi), a significant amount of energy is released. However, the hydrolysis of ADP to AMP involves the breakage of a bond that holds less energy compared to the terminal phosphate bond in ATP.
During the hydrolysis of ATP to form ADP, one phosphate group is detached with the release of around 7.4 kcal/mol of energy under standard conditions, which is roughly the energy stored in one of these high-energy bonds. However, the breakdown of ADP to AMP releases significantly less energy because the hydrolysis of the bond between the first and second phosphate groups in ADP is not as energy-rich. Specifically, this bond releases about 3 kcal/mol of energy upon hydrolysis. The amount of energy released by ATP during similar hydrolysis is more than twice this amount.
Therefore, if ADP were hydrolyzed to AMP, we would expect the reaction to release less energy than the hydrolysis of ATP to AMP due to the lower energy content of the bond being hydrolyzed. Additionally, the same amount of water would be used in both reactions, and the change in entropy would also likely be similar, assuming similar conditions except for the starting molecule.