Question

Select the correct option which shows the most appropriate temperatures of three different steps of PCR mechanism :

• A.

  	Denaturation	Primer annealing	Primer extension
  (A)	40–60°C	72°C	90°C

• B.

  	Denaturation	Primer annealing	Primer extension
  (D)	27°C	45–50°C	85–87°C

• C.

  	Denaturation	Primer annealing	Primer extension
  (C)	94–96°C	40–60°C	72°C

• D.

  	Denaturation	Primer annealing	Primer extension
  (B)	60–60°C	96°C	40–60°C

Answer 1

The correct option is C

	Denaturation	Primer annealing	Primer extension
(C)	94–96°C	40–60°C	72°C

PCR or polymerase chain reaction is the technique employed for the amplification of the gene of interest. The technique shows 3 steps of the PCR cycle, namely denaturation, annealing, and extension.
Step 1 represents the step of denaturation, where the dsDNA is divided into two ssDNA under high temperature. For denaturation to occur, an approximate temperature of 90-92°C is required.
Step 2 represents the attachment of short oligonucleotide sequences called primer by a process called annealing.
Step 3 represents the extension of the DNA segment by the addition of nucleotides by the action of the thermostable polymerase called Taq polymerase.

So, the correct answer is option -c.