Endonucleases break DNA at specific sites called

Options

A. Palindromic sequences
B. Restriction sites
C. Conserved sites
D. Both A and B

Answer

**Step-by-Step Solution:**

1. **Understanding Endonucleases**: Endonucleases are enzymes that cleave the phosphodiester bonds within a nucleic acid chain. They play a crucial role in various biological processes, including DNA repair and recombinant DNA technology.

2. **Identifying Specific Sites**: These enzymes recognize specific sequences of nucleotides in the DNA where they will make their cuts.

3. **Palindromic Sequences**: The specific sites that endonucleases target are often palindromic sequences. A palindromic sequence is one that reads the same in both directions on complementary strands of DNA. For example, the sequence GAA TTC on one strand corresponds to the sequence AAG TTA on the complementary strand.

4. **Restriction Sites**: The sites where endonucleases cut the DNA are referred to as restriction sites. These sites are crucial for genetic engineering and molecular cloning, as they allow for the precise cutting and manipulation of DNA.

5. **Conclusion**: Therefore, the answer to the question is that endonucleases break DNA at specific sites called **restriction sites**.

**Final Answer**: Endonucleases break DNA at specific sites called **restriction sites**.

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