The correct statement about ptyalin and pancreatic amylase is :

Options

A. Ptyalin breaks down only uncooked starch in acidic medium while pancreatic amylase breaks down only uncooked starch in alkaline medium.
B. Ptyalin breaks down only cooked starch in alkaline medium while pancreatic amylase breaks down only uncooked starch in acidic medium.
C. Ptyalin breaks down only uncooked starch in acidic medium while pancreatic amylase breaks down only cooked starch in alkaline medium.
D. Ptyalin breaks down only cooked starch in acidic medium while pancreatic amylase breaks down only uncooked starch in alkaline medium.

Answer

To solve the question regarding the correct statement about ptyalin and pancreatic amylase, we need to analyze the function of each enzyme and the conditions under which they operate.

### Step-by-Step Solution:

1. **Understanding Ptyalin**:
- Ptyalin is an enzyme found in saliva, also known as salivary amylase.
- Its primary function is to break down starch into simpler sugars.
- Ptyalin works best in an acidic medium (the pH of saliva is slightly acidic).

2. **Understanding Pancreatic Amylase**:
- Pancreatic amylase is produced in the pancreas and released into the small intestine.
- This enzyme also breaks down starch, but it operates in an alkaline medium (the pH in the small intestine is alkaline due to the presence of bicarbonate).

3. **Analyzing the Statements**:
- **Statement 1**: "Ptyalin breaks down only uncooked starch in the acidic medium while pancreatic amylase breaks down only uncooked starch in alkaline medium."
- This is incorrect because ptyalin can break down cooked starch as well.
- **Statement 2**: "Ptyalin breaks down only cooked starch in alkaline medium while pancreatic amylase breaks down only uncooked starch in acidic medium."
- This is incorrect because ptyalin works in an acidic medium and breaks down cooked starch, while pancreatic amylase works in an alkaline medium.
- **Statement 3**: "Ptyalin breaks down only uncooked starch in acidic medium while pancreatic amylase breaks down only uncooked starch in alkaline medium."
- This is incorrect because ptyalin can break down cooked starch.
- **Statement 4**: "Ptyalin breaks down only cooked starch in the acidic medium while pancreatic amylase breaks down only uncooked starch in alkaline medium."
- This is the correct statement. Ptyalin does break down cooked starch in acidic conditions, and pancreatic amylase breaks down uncooked starch in alkaline conditions.

4. **Conclusion**:
- The correct answer is **Statement 4**: "Ptyalin breaks down only cooked starch in the acidic medium while pancreatic amylase breaks down only uncooked starch in alkaline medium."