Name the enzyme that prevents sealing or joining of the sticky ends of vector :

Options

A. DNA ligase
B. Alkaline phosphatase
C. RNAase
D. Restriction phosphates

Answer

To answer the question regarding the enzyme that prevents the sealing or joining of the sticky ends of a vector, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Sticky Ends**:
- Sticky ends are overhanging sequences of DNA that are created when restriction enzymes cut DNA at palindromic sequences. These ends can easily pair with complementary sticky ends of other DNA fragments.

2. **Role of DNA Ligase**:
- DNA ligase is the enzyme responsible for sealing or joining the sticky ends of DNA fragments. It catalyzes the formation of phosphodiester bonds between adjacent nucleotides.

3. **Identifying the Enzyme that Prevents Joining**:
- To prevent the joining of sticky ends, we need an enzyme that can remove or alter the components necessary for ligation.

4. **Enzyme Choice**:
- Alkaline phosphatase is the enzyme that removes phosphate groups from the 5' ends of DNA. Since DNA ligase requires these phosphate groups to seal the sticky ends, the removal of phosphates by alkaline phosphatase prevents the joining of the DNA fragments.

5. **Conclusion**:
- Therefore, the enzyme that prevents the sealing or joining of the sticky ends of a vector is **alkaline phosphatase**.

### Final Answer:
**Alkaline phosphatase**

---