Digestion of both starch and protein is done by

Options

A. gastric lipase
B. ptyalin enzyme
C. gastric juice
D. pancreatic juice

Answer

To solve the question regarding which substance is responsible for the digestion of both starch and protein, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Components of Digestion**:
- Digestion involves breaking down complex molecules into simpler forms that can be absorbed by the body.
- Starch is a carbohydrate, and proteins are made up of amino acids.

2. **Identify the Enzymes Involved**:
- Different enzymes are responsible for the digestion of different types of macromolecules.
- For starch, the enzyme amylase is responsible for breaking it down into simpler sugars (monosaccharides).
- For proteins, enzymes such as trypsin, chymotrypsin, and elastase are involved in breaking them down into amino acids.

3. **Consider the Sources of These Enzymes**:
- Amylase is found in saliva (ptyalin) and pancreatic juice.
- The enzymes for protein digestion (trypsin, chymotrypsin, elastase) are produced in the pancreas and secreted into the small intestine as part of pancreatic juice.

4. **Evaluate the Options Provided**:
- **Gastric lipase**: Primarily digests fats, not starch or proteins.
- **Ptyalin enzyme**: Digests starch but not proteins.
- **Gastric juice**: Contains hydrochloric acid and pepsin, which digests proteins but does not digest starch.
- **Pancreatic juice**: Contains both amylase (for starch) and proteases (like trypsin and chymotrypsin for proteins).

5. **Conclusion**:
- The only option that digests both starch and protein is **pancreatic juice** because it contains both amylase and proteolytic enzymes.

### Final Answer:
The digestion of both starch and protein is done by **pancreatic juice**.

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