Pretest: Unit 2

Based on the information shown, which enzyme would work best in the stomach?

| Time | Enzyme I | Enzyme II | Enzyme III | Enzyme IV |
|-------|----------|-----------|------------|-----------|
| 2-4 | Inactive | Inactive | High | Low |
| 4-6 | Inactive | Low | Low | High |
| 6-7 | Low | High | Inactive | Low |
| 7-9 | High | Low | Inactive | Inactive |
| 9-11 | Low | Inactive | Inactive | Inactive |

A. Enzyme I
B. Enzyme II
C. Enzyme III
D. Enzyme IV



Answer :

To determine which enzyme would work best in the stomach, we need to consider the pH environment of the stomach and match it with the activity ranges of the enzymes provided in the data.

The stomach typically has a very low pH, around pH 2, due to the presence of gastric acid. This environment is highly acidic.

Given the pH ranges in the activity table:

- Enzyme I:
- pH 2-4: Inactive
- pH 4-6: Inactive
- pH 6-7: Low
- pH 7-9: High
- pH 9-11: Low

- Enzyme II:
- pH 2-4: Inactive
- pH 4-6: Low
- pH 6-7: High
- pH 7-9: Low
- pH 9-11: Inactive

- Enzyme III:
- pH 2-4: High
- pH 4-6: Low
- pH 6-7: Inactive
- pH 7-9: Inactive
- pH 9-11: Inactive

- Enzyme IV:
- pH 2-4: Low
- pH 4-6: High
- pH 6-7: Low
- pH 7-9: Inactive
- pH 9-11: Inactive

Now, let's evaluate the enzymes with respect to their activity at pH 2:

- Enzyme I is inactive at pH 2.
- Enzyme II is inactive at pH 2.
- Enzyme III is highly active at pH 2.
- Enzyme IV has low activity at pH 2.

Among these enzymes, Enzyme III exhibits high activity at the low pH typical of the stomach, making it the most suitable for functioning in these conditions.

Thus, the enzyme that would work best in the stomach is:

C. Enzyme III