Biology Enzymes MDCAT 2019
PMDC Verified Question 60 of 79
According to ____ model, the active site of enzyme is modified as the substrate interacts with enzyme.
A
Lock and key
B
Fluid mosaic
C
Induced fit
D
Emil Fischer
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Induced fit
Concept:

The interaction between an enzyme and its substrate is dynamic, not rigid. The enzyme's active site undergoes conformational changes upon substrate binding.

Solution:

  • The Induced Fit model, proposed by Daniel Koshland in 1959, suggests that the active site is flexible.
  • When a substrate combines with the enzyme, it induces a conformational change in the enzyme's structure.
  • This change aligns the catalytic groups perfectly to perform the reaction efficiently.


Why other options are incorrect:

The Lock and Key model (proposed by Emil Fischer) assumes a rigidly shaped active site that never changes. The Fluid Mosaic model describes cell membranes, not enzymes.

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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