Explain the reasons for the key steps involved in 'PCR'?
In PCR, a reaction takes place in an eppendorf tube, where the primer strand is added from outside in the form of a deoxyoligonucleotide, and DNA polymerase enzyme is added to help in polymerization. Unlimited supply of amplified DNA is obtained by repeating the reaction, which is made possible by regular denaturation of freshly synthesized double stranded DNA molecules by heating it to 90-98 degree centigrade.
At this high temperature the two strands separate. Once the double stranded DNA is made single stranded by heating upto 90-98 degree centigrade, the mixture with two primers, recognizing the two strands and bordering the sequence to be amplified is cooled to 40-60 degree centigrade. This allows the primers to bind to their complementary strands through renaturation.