Biology Enzymes UHS 2022
PMDC Verified Question 46 of 79
Enzymes lower the activation energy by stabilizing the transition state of a metabolic reaction due to:
A
Distorting the molecules in the allosteric site
B
Changing conditions within the active site
C
Changing conditions within the protein framework
D
Rearranging the fatty acids in active site
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Changing conditions within the active site
Concept:

Activation energy is lowered when an enzyme makes it physically and chemically easier for substrates to reach the unstable transition state.

Solution:

  • When a substrate binds to the active site, the enzyme subtly alters the microenvironment.
  • By changing conditions within the active site (such as altering the local pH, adjusting charge distribution, or putting mechanical stress on specific bonds), the enzyme stabilizes the transition state, requiring less energy for the reaction to proceed.


Why other options are incorrect:

Changes in the general protein framework or allosteric site are related to regulation, not the direct catalytic mechanism. Active sites are composed of amino acids, not fatty acids.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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