The substrate for restriction enzyme is-

Options

A. Single standed RNA
B. Proteins
C. Double standed DNA
D. Single stranded DNA

Answer

**Step-by-Step Solution:**

1. **Understanding Restriction Enzymes**:
- Restriction enzymes, also known as restriction endonucleases, are proteins that cut DNA at specific sequences. They are crucial tools in molecular biology for manipulating DNA.

2. **Identifying the Substrate**:
- The substrate for restriction enzymes is the type of molecule they act upon. In this case, restriction enzymes specifically target DNA.

3. **Analyzing the Options**:
- The question provides four options:
1. Single stranded RNA
2. Two stranded proteins
3. Three stranded DNA
4. Double stranded DNA
- We need to determine which of these options is the correct substrate for restriction enzymes.

4. **Eliminating Incorrect Options**:
- **Single stranded RNA**: Restriction enzymes do not act on RNA; they specifically target DNA.
- **Two stranded proteins**: Proteins are not substrates for restriction enzymes; they act on nucleic acids (DNA/RNA).
- **Three stranded DNA**: This is not a common form of DNA; restriction enzymes do not act on this structure.
- **Double stranded DNA**: This is the correct substrate for restriction enzymes, as they cleave DNA at specific sequences.

5. **Conclusion**:
- Based on the analysis, the substrate for restriction enzymes is **Double stranded DNA**.

**Final Answer**: The substrate for restriction enzymes is **Double stranded DNA**.

---