The number of nucleotides present in the restriction sequence of the first restriction endonuclease is

Options

A. 6
B. 8
C. 12
D. 16

Answer

To solve the question regarding the number of nucleotides present in the restriction sequence of the first restriction endonuclease, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the First Restriction Endonuclease**:
- The first restriction endonuclease discovered is HindIII (often abbreviated as HIND3).

2. **Understand the Function of Restriction Endonucleases**:
- Restriction endonucleases are enzymes that cut DNA at specific sequences, known as restriction sites.

3. **Determine the Recognition Sequence**:
- HindIII recognizes and cuts the DNA at a specific sequence. The recognition sequence for HindIII is:
```
AAGCTT
```
- This sequence is 6 nucleotides long.

4. **Count the Nucleotides**:
- The sequence "AAGCTT" consists of the following nucleotides:
- A, A, G, C, T, T
- Counting these gives us a total of 6 nucleotides.

5. **Conclusion**:
- Therefore, the number of nucleotides present in the restriction sequence of the first restriction endonuclease (HindIII) is **6**.

### Final Answer:
The number of nucleotides present in the restriction sequence of the first restriction endonuclease is **6**.

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