Apentix/AP Biology/Unit 3: Cellular Energetics/Question
AP Biologymediummcq1 pt

Why does removing the terminal phosphate from ATP release usable free energy?

A.The adenine base captures sunlight whenever its third phosphate is removed.
B.Removing the phosphate adds kinetic energy to every enzyme in the cell.
C.Repulsion among the clustered negative charges on adjacent phosphates makes ADP and inorganic phosphate more stable than intact ATP, so cleavage is exergonic.
D.The freed phosphate ion burns in the presence of cytochromes.

Explanation

Core Concept

Three phosphate groups pack negatively charged oxygens against one another, straining the molecule with continuous electrostatic repulsion. Hydrolysis separates that cluster into ADP and Pi, letting charges spread out and resonance stabilize the products. Because the products sit at lower free energy than the reactant, the reaction releases energy cells couple to transport, motion, and biosynthesis.

Correct Answer

CRepulsion among the clustered negative charges on adjacent phosphates makes ADP and inorganic phosphate more stable than intact ATP, so cleavage is exergonic.

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