Which of the following statement is true ?

Options

A. Pepsin cannot digest casein.
B. Trypsin can digest collagen.
C. Pepsin cannot digest collagen.
D. Chymotrypsin can digest casein.

Explanation

To solve the question regarding which statement is true among the given options, we will analyze each statement one by one, focusing on the enzymes mentioned: pepsin, trypsin, and chymotrypsin.

### Step-by-Step Solution:

1. **Understanding the Enzymes**:
- Pepsin, trypsin, and chymotrypsin are all proteolytic enzymes (proteases) that break down proteins into smaller peptides.

2. **Analyzing Statement 1**:
- **Statement**: Pepsin can't digest casein.
- **Analysis**: Casein is a milk protein, and pepsin can indeed digest casein. Therefore, this statement is **false**.

3. **Analyzing Statement 2**:
- **Statement**: Trypsin can't digest collagen.
- **Analysis**: Collagen is a fibrous protein found in connective tissues. Trypsin can digest some proteins but is not effective on collagen. Therefore, this statement is **true**.

4. **Analyzing Statement 3**:
- **Statement**: Pepsin can't digest collagen.
- **Analysis**: Pepsin can partially digest collagen, especially when assisted by hydrochloric acid. Therefore, this statement is **false**.

5. **Analyzing Statement 4**:
- **Statement**: Chymotrypsin can't digest casein.
- **Analysis**: Chymotrypsin can digest casein, similar to pepsin. Therefore, this statement is **false**.

### Conclusion:
The only true statement among the options is that **Trypsin can't digest collagen**.

### Final Answer:
The true statement is: **Trypsin can't digest collagen**.

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