Chemistry Macromolecules / Biochemistry UHS 2023
PMDC Verified Question 11 of 47
Competitive inhibitors stop an enzyme from working by:
A
Changing the shape of the enzyme
B
Merging with the substrate instead
C
Blocking the active site of the enzyme
D
Combining with the product of the reaction
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Blocking the active site of the enzyme
Concept:

Enzyme inhibition occurs when molecules interfere with catalysis. The mechanism defines the type of inhibition.

Formula:

$$N/A$$

Solution:

  • A competitive inhibitor is structurally similar to the enzyme's natural substrate.
  • Because of this mimicry, it binds directly to the active site, physically preventing the actual substrate from entering.
  • Thus, it stops the enzyme from working by blocking the active site of the enzyme.


Why other options are incorrect:

Changing the shape of the enzyme (allosteric shift) is characteristic of non-competitive inhibition. Inhibitors bind to the enzyme, not the substrate or the product.

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.

Previous Question All Macromolecules / Biochemistry MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App