The nucleases Cleaving nucleotides one at a time from the end of the Polynucleotide chain are :

Options

A. Specific for '5' end of RNA stand
B. Specific for '3' end of RNA stand
C. Specific for both '5' and '3' ends of nucleotides strands
D. Non-Specific for both '5' and '3' ends of nucleotides strands

Answer

To solve the question regarding the nucleases that cleave nucleotides one at a time from the end of the polynucleotide chain, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Nucleases**: Nucleases are enzymes that break down nucleic acids by hydrolyzing the bonds between nucleotides. They can be classified into two main types: exonucleases and endonucleases.

2. **Exonucleases vs. Endonucleases**:
- **Exonucleases**: These enzymes cleave nucleotides one at a time from the ends of a polynucleotide chain. They can act on either the 5' end or the 3' end of the nucleic acid.
- **Endonucleases**: These enzymes cut the polynucleotide chain at specific sites within the strand, rather than at the ends.

3. **Identifying the Correct Type**: Since the question specifically asks for nucleases that cleave nucleotides one at a time from the end of the chain, we focus on exonucleases.

4. **Conclusion**: The correct answer to the question is that the nucleases cleaving nucleotides one at a time from the end of the polynucleotide chain are **exonucleases**.

### Final Answer:
Exonucleases are the nucleases that cleave nucleotides one at a time from the end of the polynucleotide chain.

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