Question

the free-energy change for the hydrolysis of atp to adp pi, under standard conditions (1 m concentration of both reactants and products) is -7.3 kcal/mol. however, in the cytoplasm of the cell, the free-energy change is about -13 kcal/mol. based on this observation, what would you predict the free-energy change for the reverse reaction (formation of atp from adp and pi) would be under cellular conditions?

Answer 1

The reverse reaction of forming ATP from ADP and Pi under cellular conditions would have a free-energy change of +13 kcal/mol, equal in magnitude but opposite in sign to the energy released during ATP hydrolysis under those same conditions.

Step-by-step explanation:

The question pertains to the free-energy change associated with the hydrolysis of ATP to ADP and phosphate (Pi), which is relevant to understanding cellular metabolism. In standard conditions, this change is -7.3 kcal/mol, but under cellular conditions, it is about -13 kcal/mol.

Considering that reactions are reversible and energy conservation applies, the synthesis of ATP from ADP and Pi (the reverse reaction) under cellular conditions would require an input of free energy equivalent to the amount released during hydrolysis, meaning it would be +13 kcal/mol. That is to say, the free-energy change for the formation of ATP from ADP and Pi under cellular conditions would be the opposite in sign but equal in magnitude to the energy released during hydrolysis.