Exonucleases, a type of nucleases that degrade nucleic acids, remove nucleotides from

Options

A. Within the polynucleotide chain
B. End of the polynucleotide chain
C. Particular recognition sites on polynucleotide
D. End of the polypeptide chain

Answer

To solve the question regarding exonucleases and their function in degrading nucleic acids, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Exonucleases**:
- Exonucleases are enzymes that degrade nucleic acids by removing nucleotides.
- They specifically act on the ends of nucleic acid chains.

2. **Identifying the Function**:
- Exonucleases work by cleaving nucleotides one at a time from the ends of the polynucleotide chain.
- This action involves hydrolyzing the phosphodiester bonds.

3. **Analyzing the Options**:
- **Option A**: "Within the polynucleotide chain" - This is incorrect as it describes the action of endonucleases, which cut within the chain.
- **Option B**: "End of the polynucleotide chain" - This is correct because exonucleases remove nucleotides from the ends.
- **Option C**: "Particular recognition sites on polynucleotide" - This is also incorrect; it refers to the action of restriction endonucleases.
- **Option D**: "End of the polypeptide chain" - This is incorrect as it pertains to proteins, not nucleic acids.

4. **Selecting the Correct Answer**:
- Based on the analysis, the correct answer is **"end of the polynucleotide chain"**.

### Final Answer:
The correct option is **"end of the polynucleotide chain."**

---