Select the correct sequence of steps involved in PCR during gene amplification.

Options

A. Denaturation , annealing , extension
B. Denaturation , extension , annealing
C. Extension , Denaturation, Annealing
D. Annealing , extension , denaturation

Answer

To solve the question regarding the correct sequence of steps involved in PCR (Polymerase Chain Reaction) during gene amplification, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Denaturation**:
- The first step in PCR is denaturation. In this step, the double-stranded DNA template is heated to a high temperature (typically around 94-98°C). This heat causes the hydrogen bonds between the complementary bases to break, resulting in the separation of the two strands of DNA.

2. **Annealing**:
- After denaturation, the temperature is lowered (usually to around 50-65°C) in the annealing step. This allows the DNA primers, which are short sequences of nucleotides, to bind or anneal to their complementary sequences on the single-stranded DNA templates. The primers are essential for initiating the synthesis of the new DNA strands.

3. **Extension**:
- The final step is extension (or elongation). The temperature is raised again (typically to about 72°C), which is the optimal temperature for the enzyme Taq polymerase. This enzyme synthesizes new DNA strands by adding nucleotides to the 3' end of the primers, effectively creating a new strand of DNA complementary to the template strand.

### Correct Sequence:
The correct sequence of steps involved in PCR during gene amplification is:
- **Denaturation → Annealing → Extension**

Thus, the correct answer is **Option 1**.