Question

Which of the following is not a step of Polymerase Chain Reaction?

• A. Extension
• B. Downstream processing
• C. Annealing
• D. Denaturation

Answer 1

The Correct Option is B

PCR includes three main steps: denaturation, annealing, and extension. Downstream processing is a term typically associated with post-synthesis procedures in biotechnology, such as purification, and is not part of the PCR cycle.

Answer 2

The Polymerase Chain Reaction (PCR) involves the following key steps:

• Denaturation: The DNA template is heated to separate its two strands.
• Annealing: Short DNA primers bind to the complementary sequences on the single-stranded DNA.
• Extension: DNA polymerase extends the primers to synthesize new DNA strands.

Downstream processing, on the other hand, is not a step of PCR. It refers to the processes used to purify and isolate the desired product after PCR or other biotechnological techniques, like protein purification or product extraction.