Biology Enzymes NUMS 2023
PMDC Verified Question 34 of 79
In term of enzyme action, 'maximum temperature' refers to a temperature at which:
A
Enzymes start to denature
B
Enzymes start to re-nature
C
Enzymes work best
D
Enzymes are reactivated
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Enzymes start to denature
Concept:

Enzyme activity is governed by three cardinal temperatures: Minimum, Optimum, and Maximum temperatures.

Solution:

  • Optimum Temperature: The temperature at which an enzyme exhibits its maximum catalytic activity (works best, typically ~37??C in humans).
  • Maximum Temperature: The upper critical temperature at which enzymes start to denature and lose their functional tertiary/quaternary structure due to heat-induced disruption of hydrogen and ionic bonds.
  • Minimum Temperature: The lowest temperature at which enzyme activity is detectable.
  • Therefore, 'maximum temperature' specifically refers to the point where enzymes start to denature.


Why other options are incorrect:

  • B & D (Re-nature / Reactivated): Heat denaturation is generally irreversible for globular enzymes.
  • C (Enzymes work best): This defines the Optimum Temperature, not the Maximum Temperature.

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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