Biology Enzymes MDCAT 2019
PMDC Verified Question 62 of 79
Which one of the following graphs shows how the rate of reaction of pepsin is affected by pH?

A
Bell-shaped curve peaking at neutral pH (~7.0)
B
Linear increase peaking at alkaline pH (~12.0)
C
Flat horizontal line showing constant activity across all pH levels
D
Bell-shaped curve peaking at highly acidic pH (~2.0)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option D: Bell-shaped curve peaking at highly acidic pH (~2.0)
pH Rate of Reaction pH ~2.0 (Optimum) 1 3 7


Concept:

Pepsin is a powerful gastric protease secreted in the stomach, operating optimally in highly acidic conditions.

Solution:

  • Gastric hydrochloric acid (HCl) maintains a stomach pH of ~1.5 to 2.0.
  • Pepsin's enzymatic activity peaks sharply around pH 2.0, represented by the bell curve in Option D.

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