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

Breakdown of a storage polymer would occur even without its enzyme, merely over geological timescales. When the enzyme is added, what happens to the reaction's free energy change?

A.It stays exactly the same, because enzymes alter only the pathway's barrier and therefore the rate
B.It becomes more negative, since the enzyme extracts extra energy from the substrate
C.It becomes positive, showing that the reaction now requires an energy input
D.It drops to zero once the enzyme drives the process forward

Explanation

Core Concept

The free energy difference between reactants and products is fixed by their identities. An enzyme reshapes the journey, stabilizing transition states and lowering the barrier so an imperceptibly slow change finishes in milliseconds, but the destination and its energy ledger never move. Claims of a bigger energy payout, a reversed sign, or forced completion all confuse kinetics with thermodynamics.

Correct Answer

AIt stays exactly the same, because enzymes alter only the pathway's barrier and therefore the rate

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