DNA ligase is an enzyme that catalyses the

Options

A. splitting of DNA threads into small bits
B. joining of the fragments of DNA
C. denaturation of DNA
D. synthesis of DNA

Answer

**Step-by-Step Solution:**

1. **Understanding DNA Ligase**: DNA ligase is an enzyme that plays a crucial role in the process of DNA replication and repair. Its primary function is to join two DNA fragments together.

2. **Function of DNA Ligase**: The enzyme catalyzes the formation of a phosphodiester bond between the 3' hydroxyl (OH) end of one DNA fragment and the 5' phosphate end of another DNA fragment. This is essential for creating a continuous DNA strand.

3. **Analyzing the Options**:
- **Option 1**: "Splitting of DNA thread into small bits" - This is incorrect as DNA ligase does not split DNA; it joins fragments.
- **Option 2**: "Joining of DNA fragments" - This is correct as it describes the main function of DNA ligase.
- **Option 3**: "Denaturation of DNA" - This is incorrect since denaturation refers to the separation of DNA strands, which is not a function of DNA ligase.
- **Option 4**: "Synthesis of DNA" - This is also incorrect because DNA synthesis is primarily carried out by DNA polymerase, not DNA ligase.

4. **Conclusion**: Based on the analysis, the correct function of DNA ligase is the joining of DNA fragments.

**Final Answer**: DNA ligase is an enzyme that catalyzes the joining of DNA fragments.

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