In the context of Gibbs free energy, what happens when a terminal phosphate group is removed from ATP by hydrolysis?

• A. ATP remains unchanged because breaking the phosphate bond requires exactly as much energy as is released, so $\Delta G=0$.
• B. ATP is converted to ADP and inorganic phosphate, and free energy is released (the reaction has $\Delta G<0$ under typical cellular conditions).
• C. ATP is converted to ADP only (no inorganic phosphate is produced), and the reaction is strongly endergonic.
• D. ATP is converted to AMP and pyrophosphate, and free energy is absorbed (the reaction has $\Delta G>0$ under typical cellular conditions).

Answer: (B)