The restriction endonuclease enzyme binds to the DNA and cuts

Options

A. Any one stand of the double helix
B. Each of the two strands at specific points in their base-sugar bonds
C. Each of the two strands at specific points in their base-phosphate bonds
D. Each of the two strands at specific points in their sugar-phosphate backbones

Answer

### Step-by-Step Solution:

1. **Understanding Restriction Endonucleases**:
- Restriction endonucleases are enzymes that recognize specific sequences in double-stranded DNA and cut the DNA at those sites. They are essential tools in biotechnology for DNA manipulation.

2. **Mechanism of Action**:
- These enzymes bind to the DNA at specific recognition sites. Once bound, they cleave the phosphodiester bonds that link the sugar and phosphate groups in the DNA backbone.

3. **Identifying the Cut Site**:
- The enzyme does not cut randomly; it targets specific sequences, which are usually palindromic in nature. The cut occurs in the sugar-phosphate backbone of the DNA, affecting both strands of the double helix.

4. **Impact on DNA Structure**:
- The restriction endonuclease cuts each of the two strands at a specific point in their sugar-phosphate backbone. Importantly, this action does not damage the nitrogenous bases that are part of the DNA structure.

5. **Conclusion**:
- Based on the understanding of how restriction endonucleases function, the correct answer to the question is that they cut each of the two strands at specific points in their sugar-phosphate backbone.

### Final Answer:
The restriction endonuclease enzyme binds to the DNA and cuts each of the two strands at specific points in their sugar-phosphate backbone.

---