Question

Which of the following describes a key step in performing PCR?

• A. Heat shock at 42 Celsius for 90 seconds.
• B. Addition of CaCl${}_2$ to make the cells DNA.
• C. Addition of Taq polymerase to replicate the DNA.
• D. Adding RNA primers to flank the ends of the DNA that are targeted for copying.

Answer 1

The correct option is D Adding RNA primers to flank the ends of the DNA that are targeted for copying.

PCR has 3 key steps: Denaturation, annealing, and amplification. In denaturation, the DNA is heated at 75 degrees, followed by addition of RNA primers which bind or anneal to the 5' end and Taq polymerase is added that amplifies the strand resulting to amplification of DNA strand.