Biology Enzymes ETEA 2023 Retake
PMDC Verified Question 23 of 79
What alters the shape of enzyme and makes them functional:
A
Cofactor
B
Other enzymes
C
Proteins
D
Both A and C
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Cofactor
Concept:

Many enzymes are synthesized in an incomplete, non-functional state (apoenzyme) and require an external trigger to complete their specific 3D active site.

Solution:

  • Apoenzymes are inactive on their own.
  • When a specific cofactor (like a metal ion or coenzyme) binds to the apoenzyme, it physically alters the protein's conformational shape.
  • This shape change properly aligns the active site, converting the useless apoenzyme into a fully functional, active holoenzyme.


Why other options are incorrect:

While some enzymes (kinases) can activate other enzymes via phosphorylation, the universal structural requirement that completes an enzyme's shape to make it a holoenzyme is a cofactor.

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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