Identify the step, which is not involved in polymerase chain reaction?

The correct answer is Option (3) → Transduction

The polymerase chain reaction (PCR) makes many copies of a DNA segment. Each cycle has three steps: denaturation, primer annealing and extension of the primers.

(1) Annealing — A step of PCR. The primers attach to the matching regions of the single DNA strands.

(2) Extension — A step of PCR. The thermostable DNA polymerase adds nucleotides to the primers and makes the new strand.

(3) Transduction — Not a step of PCR. Transduction is the transfer of genes from one bacterium to another by a virus. PCR is done in a tube and does not use a virus.

(4) Denaturation — A step of PCR. A high temperature separates the double-stranded DNA into two single strands.

NCERT Extract:
Amplification of Gene of Interest Using PCR – “… PCR stands for Polymerase Chain Reaction. In this reaction, multiple copies of the gene (or DNA) of interest is synthesised in vitro using two sets of primers (small chemically synthesised oligonucleotides that are complementary to the regions of DNA) and the enzyme DNA polymerase. The enzyme extends the primers using the nucleotides provided in the reaction and the genomic DNA as template.”