Biology Enzymes UHS 2022
PMDC Verified Question 56 of 79
Non-competitive inhibitor molecules have:
A
A similar structure to the normal substrate molecule
B
A quite different structure from the substrate molecule
C
A different conformation but fit into the active site
D
A similar conformation but does not fit into the 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: A quite different structure from the substrate molecule
Concept:

The physical shape of an inhibitor dictates where it will bind on the enzyme, determining its entire mechanism of action.

Solution:

  • Because non-competitive inhibitors do not bind to the active site, they do not need to mimic the substrate's shape.
  • Instead, they bind to a completely separate allosteric site on the enzyme's surface.
  • Therefore, they possess a quite different structure from the substrate molecule.


Why other options are incorrect:

Having a similar structure is the defining trait of a competitive inhibitor, which allows it to fit into the active site.

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