Question

Comment upon PCR.

Hint:

Remember that PCR amplifies a specific segment of DNA, and it involves repeated cycles of denaturation, annealing, and extension. It's widely used in forensics, cloning, and diagnostics.

Answer 1

Polymerase Chain Reaction (PCR):
Polymerase Chain Reaction (PCR) is a revolutionary laboratory technique used to amplify a specific segment of DNA. Developed by Kary Mullis in 1983, PCR allows scientists to produce millions of copies of a particular DNA segment in a short period. The process involves the following steps:
1. **Denaturation:** The DNA sample is heated to around 94°C to separate the double-stranded DNA into two single strands.
2. **Annealing:** The reaction temperature is lowered to around 50–60°C, allowing short DNA primers to bind to the complementary sequences on the single-stranded DNA.
3. **Extension:** The temperature is increased to around 72°C, and a heat-stable DNA polymerase enzyme (such as Taq polymerase) is used to synthesize a new DNA strand complementary to the template strand.
PCR is widely used in various applications such as DNA cloning, gene analysis, forensics, and medical diagnostics. It has become an essential tool in modern molecular biology.