Biology Enzymes NUMS 2023
PMDC Verified Question 33 of 79
Most enzymes work best at the following temperature:
A
\( 30^{\circ}\text{C} \)
B
\( 40^{\circ}\text{C} \)
C
\( 50^{\circ}\text{C} \)
D
\( 20^{\circ}\text{C} \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: \( 40^{\circ}\text{C} \)
Concept:

The rate of an enzyme-catalyzed reaction increases with heat due to higher kinetic energy, up to a strict limit where the protein structure breaks down.

Solution:

  • For most human/mammalian enzymes, reaction rates peak just before the onset of thermal denaturation.
  • This optimal kinetic peak occurs around \( 37^{\circ}\text{C} \) to \( 40^{\circ}\text{C} \).
  • At \( 40^{\circ}\text{C} \), molecular collisions are maximized while the 3D protein structure remains largely intact.


Why other options are incorrect:

\( 50^{\circ}\text{C} \) destroys (denatures) most human enzymes. \( 20^{\circ}\text{C} \) and \( 30^{\circ}\text{C} \) do not provide enough kinetic energy for the reaction to reach its maximum possible rate.

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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