Which of the following cuts the DNA from specific places :

Options

A. Restriction endonuclease (EcoRI)
B. Ligase
C. Exonuclease
D. Alkaline phosphate

Answer

To solve the question "Which of the following cuts the DNA from specific places?" we need to analyze the options provided:

1. **Restriction Endonuclease (E. coli)**:
- This enzyme recognizes specific sequences in DNA, known as restriction sites, which are typically 4-6 base pairs long.
- It cuts the DNA at these specific sites, resulting in DNA fragments.
- This property makes restriction endonucleases essential tools in genetic engineering.

2. **Ligase**:
- This enzyme is responsible for joining two large molecules together by forming chemical bonds.
- For DNA, DNA ligase specifically joins two DNA fragments by creating phosphodiester bonds between nucleotides.
- It does not cut DNA but rather connects fragments.

3. **Exonuclease**:
- Exonucleases remove nucleotides one at a time from the ends of a polynucleotide chain.
- They shorten the DNA molecule but do not cut it into fragments.

4. **Alkaline Phosphatase**:
- This enzyme removes phosphate groups from various molecules, including nucleotides and proteins.
- It does not cut DNA but modifies it by removing phosphate groups.

Based on this analysis, the only enzyme that cuts DNA at specific sites is **Restriction Endonuclease (E. coli)**.

### Final Answer:
The correct answer is **A. Restriction Endonuclease (E. coli)**.

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