Biology Enzymes NUMS 2024
PMDC Verified Question 8 of 79
An enzyme is capable of acting on a wide range of related substrates. Which of the following is a property of this enzyme?
A
Inflexible active site
B
Regulatory enzyme
C
Non-regulatory enzyme
D
Highly specific enzyme
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Non-regulatory enzyme
Concept:

Enzyme specificity ranges from absolute specificity (acting on only one substrate) to group/relative specificity (acting on structurally related substrates).

Solution:

  • Non-regulatory enzymes: Many non-regulatory enzymes (such as general digestive enzymes like chymotrypsin, pepsin, and lipases) possess flexible active sites that accommodate a wide range of structurally related substrates (e.g., cleaving different peptide or ester bonds).
  • Regulatory (Allosteric) enzymes: These act as critical rate-limiting pacemakers of metabolic pathways. They must be highly specific for their substrate and regulatory effectors to prevent uncontrolled metabolic flux.
  • An enzyme acting on a broad range of related substrates conforms to the Induced Fit Model (flexible active site) and functions as a Non-regulatory enzyme.


Why other options are incorrect:

  • A (Inflexible active site): An inflexible active site (Lock and Key model) would confer rigid, absolute specificity to only one exact molecule, not a wide range.
  • B (Regulatory enzyme): Regulatory enzymes are highly specialized and strictly specific for precise metabolic control.
  • D (Highly specific enzyme): Directly contradicts the question stem stating the enzyme acts on a "wide range of related substrates".

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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