Restriction endonucleases are enzymes that

Options

A. Restrict the action of other enzymes
B. Break phosphodiester bond between specific nucleotides of DNA
C. Break nucleus into pieces
D. Break H-bond between two strands of DNA

Answer

### Step-by-Step Solution:

1. **Understanding Restriction Endonucleases**:
- Restriction endonucleases are enzymes that are primarily derived from bacteria. They play a crucial role in molecular biology.

2. **Function of Restriction Endonucleases**:
- These enzymes are responsible for cleaving (cutting) DNA at specific sequences. This means they can target particular sites in the DNA molecule.

3. **Identifying the Bonds They Break**:
- The specific bonds that restriction endonucleases break are known as phosphodiester bonds. These bonds connect the sugar and phosphate groups in the DNA backbone.

4. **Conclusion**:
- Therefore, the correct answer to the question is that restriction endonucleases are enzymes that break the phosphodiester bond between specific nucleotides of DNA.

### Final Answer:
Restriction endonucleases are enzymes that break phosphodiester bonds between specific nucleotides of DNA.

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