Apentix/AP Biology/Unit 1: Chemistry of Life/Question
AP Biologymediummcq1 pt

A reaction coordinate diagram plots energy against reaction progress for an uncatalyzed reaction. When the matching enzyme is added, which feature of the diagram changes?

A.The energy levels of the reactants and products drop to new values.
B.The curve flattens so the reaction no longer passes through any energy maximum.
C.The peak between reactants and products moves lower, shrinking the barrier the molecules must climb.
D.The direction of the reaction reverses so products become reactants.

Explanation

Core Concept

The peak represents the transition state, and its height above the reactants equals the activation energy. An enzyme provides an alternative path in which active-site contacts stabilize the strained, half-bonded arrangement at the top of the curve. A lower peak means a larger fraction of substrate molecules carries enough kinetic energy to cross the barrier at any moment, so the reaction races ahead. Reactant and product plateaus stay exactly where they were, preserving the overall energy yield of the reaction.

Correct Answer

CThe peak between reactants and products moves lower, shrinking the barrier the molecules must climb.

More Unit 1: Chemistry of Life practice questions

Try a random question →

Practice more AP Biology questions with full explanations

Practice Unit 1: Chemistry of Life Questions →