Thermostable enzymes 'Taq and Pfu' isolated from thermophilic bacteria are

Options

A. RNA polymerases
B. DNA polymerases
C. restriction endonucleases
D. DNA ligases

Answer

To answer the question regarding the thermostable enzymes 'Taq' and 'Pfu' isolated from thermophilic bacteria, we will follow these steps:

### Step 1: Understand the Context
- **Thermophilic Bacteria**: These are organisms that thrive at high temperatures, typically above 45°C. They possess enzymes that are stable and functional at elevated temperatures.

### Step 2: Identify the Enzymes
- **Taq and Pfu**: These are specific enzymes derived from thermophilic bacteria. Taq polymerase is derived from *Thermus aquaticus*, and Pfu polymerase is derived from *Pyrococcus furiosus*.

### Step 3: Determine the Function of the Enzymes
- **Role in PCR**: Both Taq and Pfu polymerases are primarily used in the Polymerase Chain Reaction (PCR) technique, which is a method used to amplify DNA.

### Step 4: Classify the Enzymes
- **Enzyme Classification**: Taq and Pfu are both classified as DNA polymerases. They catalyze the synthesis of new DNA strands by adding nucleotides to a growing DNA chain during the PCR process.

### Step 5: Eliminate Other Options
- **RNA Polymerase**: This enzyme synthesizes RNA from a DNA template and is not involved in DNA amplification.
- **Restriction Endonucleases**: These enzymes cut DNA at specific sequences and are not involved in DNA synthesis.
- **DNA Ligases**: These enzymes join DNA fragments together but do not synthesize new strands.

### Conclusion
Based on the above analysis, the correct answer is that Taq and Pfu are **DNA polymerases**.

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