During the process of gene amplification using PCR, if very high temperature is not maintained in the beginning, then which of the following steps of PCR will be affected first?
- Ligation
- Annealing
- Extension
- Denaturation
Answer
(4) Denaturation
Solution
Each PCR cycle has three steps: denaturation → annealing → extension.
The first step, denaturation, separates the two strands of double-stranded DNA by heating to a high temperature (about 94 C).
⇒ If the high temperature is not maintained at the beginning, denaturation is affected first (and then the later steps cannot proceed).
Ligation is not a step of PCR.
Answer: (4)