The nuclease enzyme which brings its attack from the free and of a Polynucleotide, is called

Options

A. Polymerase
B. Endonuclease
C. Exonuclease
D. Kinase

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the nuclease enzyme that attacks from the free end of a polynucleotide. We need to identify which of the given options fits this description.

2. **Analyzing the Options**:
- **Option 1: Polymerase**: This enzyme synthesizes DNA molecules from deoxyribonucleotides. It does not attack from the free end, so this option is incorrect.

- **Option 2: Endonuclease**: This enzyme cleaves the phosphodiester bonds within a polynucleotide chain. It does not act from the free end, making this option incorrect as well.

- **Option 3: Exonuclease**: This enzyme attacks the free or external ends of a polynucleotide chain. It can act on either the 3' or 5' ends of the nucleotide sequence, making this option correct.

- **Option 4: Kinase**: This enzyme adds phosphate groups to other molecules. It does not cleave nucleotides and is not relevant to the question, so this option is also incorrect.

3. **Conclusion**: After analyzing all the options, the correct answer is **exonuclease** as it is the enzyme that attacks from the free end of a polynucleotide.

### Final Answer:
The nuclease enzyme which brings its attack from the free end of a polynucleotide is called **exonuclease**.

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