If the temperature is raised from 37°C to 70°C, how would this change affect the activity of an enzyme that functions optimally at normal body temperature and physiological pH?
I. The enzyme’s activity will decrease as the temperature rises from 37°C to 70°C, improving the rate of reaction.
II. The enzyme’s activity will decrease because the high temperature will likely denature the enzyme, reducing its effectiveness.
III. The enzyme may become completely inactive at 70°C due to irreversible denaturation.
IV. The enzyme’s activity will initially increase as the temperature rises but then decrease sharply as it approaches 70°C due to denaturation.

• A. II and III
• B. II and IV
• C. II, III, and IV
• D. I, II, III, and IV

Answer: (C)