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Class 12th Biology 2012 Set1 Outside Delhi Board Paper Solution

Question 23

How is the amplification of a gene sample of interest carried out using Polymerase Chain Reaction (PCR)?

Polymerase Chain Reaction is the amplification of gene of interest that is synthesized with two sets of primers and DNA polymerase enzyme. This DNA polymerase is thermostable which is isolated from a bacterium Thermus aquaticus called as Taq polymerase.
PCR involves three steps-
(i) Denaturation- Heating the double stranded DNA upto 98°C cause the separation of two DNA strands.
(ii) Annealing- The two sets of primer are added which bind to appropriate complementary segment of DNA strands.
(iii) Extension- Polymerisation of nucleotide chain by the enzyme Taq polymerase using the nucleotides provided in the medium.