DNA dependent DNA polymerases catalyse polymerization of DNA in

Options

A. Only 3. `to` 5. direction
B. Only 5. `to` 3.direction
C. Both direction
D. Irregular directions

Answer

To solve the question "DNA dependent DNA polymerases catalyse polymerization of DNA in," we will analyze the options provided and understand the function of DNA dependent DNA polymerases.

### Step-by-Step Solution:

1. **Understanding DNA Polymerases**:
- DNA dependent DNA polymerases are enzymes that synthesize DNA molecules from deoxyribonucleotides, the building blocks of DNA. They play a crucial role in DNA replication.

2. **Direction of Polymerization**:
- DNA polymerases can only add nucleotides to the growing DNA strand in a specific direction. This is a fundamental property of these enzymes.

3. **Identifying the Direction**:
- The direction of DNA synthesis is always from the 5' end to the 3' end of the new strand. This means that nucleotides are added to the 3' hydroxyl (-OH) group of the growing DNA strand.

4. **Evaluating the Options**:
- **Option A**: "Only three to five direction" - This is incorrect because DNA polymerases do not synthesize DNA in this direction.
- **Option B**: "Only five to three direction" - This is correct as DNA polymerases synthesize DNA by adding nucleotides to the 3' end of the growing strand.
- **Option C**: "Both direction" - This is incorrect because DNA polymerases only work in one direction.
- **Option D**: "Irregular direction" - This is also incorrect as polymerization occurs in a specific direction.

5. **Conclusion**:
- The correct answer is **Option B**: "only five to three direction".