Why is the ΔG of ATP hydrolysis in the cell about twice as great as the ΔG of ATP hydrolysis in a test tube under standard conditions?
A) A cell is an open system, whereas a test tube is a closed system.
B) ATP hydrolysis in a test tube releases more heat than ATP hydrolysis associated with cellular metabolism.
C) Reactant and product concentrations in the test tube are different from those in the cell.
D) ATP hydrolysis in cells is catalysed by enzymes, whereas the reaction in a test tube occurs spontaneously.

Question

Quizplus · Accepted Answer

Reactant and product concentrations in the test tube are different from those in the cell. The ΔG of ATP hydrolysis in the cell is higher than in a test tube because the concentrations of reactants and products in the cell are different from those used in a test tube under standard conditions. In the cell, the concentrations of ADP, phosphate, and H+ are relatively high, while the concentration of ATP is relatively low. This contributes to a greater ΔG value for ATP hydrolysis in the cell compared to a test tube.

Why Is the ΔG of ATP Hydrolysis in the Cell