The correct order of steps in polymerase chain reaction (PCR) is

Options

A. Denaturation , Extension , Annealing
B. Annealing , Extension , Denaturation
C. Extension , Denaturation , Annealing
D. Denaturation , Annealing , Extension

Answer

D

Explanation

The Polymerase Chain Reaction (PCR) involves three basic steps , denaturation , annealing and extension . In the denaturation step , DNA is heated at high temperature `(94^(@)C ` to `96^(@)C`) to separate the two strands . In the next step (annealing ) , the two oligo-nucleotide primers anneal to each single - stranded template DNA.
This step is carried out at a lower temperature (`40^(@)C` to `60^(@)C`) . The final step is extension , where in Taq DNA polymerase synthesises the DNA region between the primers , using dNTPs (deoxynucleoside triphosphates) and `Mg^(2+)` ions.