Question

In five sentences or less paraphrase polermerase chain reaction (PCR) in your own words clearly but concisely enough that someone could visualize what is happening. Include five steps, processes or stages.

Answer 1

1. Firstly, DNA has to be purified for amplifying the desired gene segment.

2. Then the dNTPs (dTTP, dATP, dCTP, dGTP), primers, T_aq polymerase and Mg⁺⁺ are added to the thermal recycler machine.

3. Now the purified double stranded DNA is denatured into single strands by heating 92°-95° C for about 1 minute.

4. The temperature of the reaction is lowered to 45°-65° C which causes primer binding, also called hybridization or annealing to the denatured, single stranded DNA.

5. Finally, the reaction temperature is adjusted between 65°-75° C and T_aq polymerase uses the primers as the starting point to synthesize the new DNA by adding nucleotides in 5' to 3' direction, known as extension phase.