Question

What is polymerase chain reaction (PCR)?

Hint:

PCR is an essential technique for amplifying DNA sequences and is widely used in diagnostics, genetic testing, and forensic science.

Answer 1

Step 1: Understanding PCR.
Polymerase Chain Reaction (PCR) is a molecular biology technique used to amplify a specific segment of DNA. It allows the production of millions of copies of a particular DNA sequence from a small initial sample. PCR is widely used in various applications such as cloning, gene analysis, and diagnostic testing.
Step 2: Conclusion.
PCR enables the rapid and specific amplification of DNA, making it a powerful tool for genetic analysis and research.
ii. Describe three steps involved in the mechanism of PCR.
Solution:
Step 1: The Three Key Steps of PCR.
The PCR process involves three main steps that are repeated for several cycles:
1. Denaturation: The DNA sample is heated to around 94-98°C to separate the two strands of the DNA template. This results in single-stranded DNA.
2. Annealing: The reaction temperature is lowered to around 50-65°C, allowing short primers to bind to the complementary sequences on the single-stranded DNA.
3. Extension (Elongation): The temperature is raised to 72°C, and a heat-stable DNA polymerase (such as Taq polymerase) synthesizes the new DNA strand by adding nucleotides to the primer.
Step 2: Conclusion.
These three steps – denaturation, annealing, and extension – are repeated in multiple cycles to exponentially amplify the target DNA.