Question

What is polymerase chain reaction (PCR)?
Describe three steps involved in mechanism of PCR.

Hint:

PCR amplifies DNA exponentially; each cycle doubles the target sequence.

Answer 1

i. PCR: A molecular biology technique used to amplify specific DNA segments in vitro, utilizing thermal cycling, primers, and DNA polymerase to produce multiple copies of a DNA sequence.
ii. Steps in PCR:
1. Denaturation: Heating to 94–98°C to separate double-stranded DNA into single strands.
2. Annealing: Cooling to 50–65°C to allow primers to bind to complementary DNA sequences.
3. Extension: Heating to 72°C for DNA polymerase to synthesize new DNA strands from primers.
Answer: i. DNA amplification technique; ii. Denaturation, annealing, extension.