Both starch and proteins are digested by -

Options

A. Saliva
B. Pancreatic juice
C. Gastric juice
D. Bile

Answer

To answer the question "Both starch and proteins are digested by -", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Components**:
- Starch is a carbohydrate, and proteins are macromolecules made up of amino acids. Both need to be broken down into simpler forms for absorption in the body.

2. **Identifying Digestive Juices**:
- The options provided are saliva, pancreatic juice, and gastric juice. We need to analyze which of these can digest both starch and proteins.

3. **Analyzing Saliva**:
- Saliva contains the enzyme salivary amylase, which is responsible for the digestion of starch. However, it does not contain enzymes that digest proteins.

4. **Analyzing Pancreatic Juice**:
- Pancreatic juice contains several enzymes:
- Pancreatic amylase: Digests starch into simpler sugars.
- Trypsinogen (activated to trypsin): Digests proteins into peptides.
- Chymotrypsinogen (activated to chymotrypsin): Also digests proteins.
- Procarboxypeptidase (activated to carboxypeptidase): Further digests proteins.
- Therefore, pancreatic juice contains enzymes that can digest both starch and proteins.

5. **Analyzing Gastric Juice**:
- Gastric juice contains pepsin, which digests proteins, but it does not contain enzymes for starch digestion.

6. **Conclusion**:
- Since pancreatic juice is the only digestive juice that contains enzymes capable of digesting both starch and proteins, the correct answer is **pancreatic juice**.

### Final Answer:
Both starch and proteins are digested by **pancreatic juice**.

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