Molecular scissor is :

Options

A. Restriction endonuclease
B. Helicase
C. Urease
D. Peptidase

Explanation

**Step-by-Step Solution:**

1. **Understanding the Term "Molecular Scissor":** The term "molecular scissor" refers to an enzyme that can cut or cleave DNA at specific locations.

2. **Identifying the Options:**
- A) Restriction Endonuclease
- B) Helicase
- C) Urease
- D) Peptidase

3. **Analyzing Each Option:**
- **Restriction Endonuclease:** This enzyme is specifically known for cutting DNA at particular recognition sites. This ability to cleave DNA is why it is often referred to as a "molecular scissor."
- **Helicase:** This enzyme unwinds the double-stranded DNA, but it does not cut the DNA.
- **Urease:** This enzyme catalyzes the hydrolysis of urea into ammonia and carbon dioxide, not related to DNA.
- **Peptidase:** This class of enzymes breaks down peptides into amino acids, and is not involved in DNA manipulation.

4. **Conclusion:** Based on the analysis, the correct answer is **A) Restriction Endonuclease**, as it is the enzyme that acts as a molecular scissor by cleaving DNA at specific sites.

**Final Answer:** Molecular scissor is a restriction endonuclease.

---