Which of the following enzymes affect the process of synthesis of new DNA chain?

Options

A. Restriction endonuclease
B. Mutase
C. Ribonuclease
D. Polymerase ।

Answer

To determine which enzyme affects the synthesis of a new DNA chain, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding the Role of Enzymes in DNA Synthesis**:
- DNA synthesis involves several key enzymes, primarily DNA polymerases, which are responsible for adding nucleotides to the growing DNA strand.

2. **Evaluating Each Option**:
- **Option 1: Restriction Endonuclease**:
- These enzymes cut DNA at specific sequences. They do not synthesize DNA; rather, they are used in molecular cloning and genetic engineering.
- **Conclusion**: This option does not affect DNA synthesis.

- **Option 2: Mutase**:
- Mutases are isomerases that catalyze the rearrangement of molecules. They do not play a role in DNA synthesis.
- **Conclusion**: This option does not affect DNA synthesis.

- **Option 3: Ribonuclease**:
- Ribonucleases degrade RNA molecules. Since they target RNA, they do not participate in the synthesis of DNA.
- **Conclusion**: This option does not affect DNA synthesis.

- **Option 4: Polymerase 1**:
- DNA Polymerase 1 is a crucial enzyme in DNA replication. It synthesizes new DNA strands by adding nucleotides complementary to the template strand.
- **Conclusion**: This option directly affects DNA synthesis.

3. **Final Answer**:
- Based on the analysis, the enzyme that affects the process of synthesis of a new DNA chain is **Polymerase 1**. Therefore, the correct answer is **Option 4**.