Denaturation is a step in the procedure called polymerase chain Reaction . This step does not involve which of the following process ?

Options

A. Breaking of hydrogen bonds of the original DNA double helix
B. Heating of starting solution to `94^@C`
C. Addition of nucleotides to the primer by DNA polymerase
D. Creation of single - stranded DNA templates

Answer

To solve the question regarding the denaturation step in the Polymerase Chain Reaction (PCR), we need to analyze what denaturation entails and what processes are involved.

### Step-by-Step Solution:

1. **Understanding Denaturation**:
- Denaturation in PCR refers to the process where the double-stranded DNA (dsDNA) is separated into two single strands. This is achieved by breaking the hydrogen bonds between the complementary base pairs.

2. **Identifying the Processes Involved**:
- **Breaking of Hydrogen Bonds**: This is a key feature of denaturation. The hydrogen bonds between the bases of the DNA strands are broken, allowing the strands to separate.
- **Heating the Solution**: Denaturation typically occurs at high temperatures, around 91-95 degrees Celsius. This heating is essential to provide the energy needed to break the hydrogen bonds.
- **Creation of Single-Stranded DNA**: After denaturation, the result is two single-stranded DNA templates that can be used in subsequent steps of PCR.

3. **Identifying the Process Not Involved**:
- **Addition of Nucleotides**: This process does not occur during the denaturation step. The addition of nucleotides happens in the next step of PCR, known as the extension phase, where DNA polymerase adds nucleotides to the primers to synthesize new DNA strands.

4. **Conclusion**:
- The process that does not occur during the denaturation step of PCR is the addition of nucleotides.

### Final Answer:
- The process that does not involve denaturation in PCR is **the addition of nucleotides**.