Question

What is the PCR sequence?

Hint:

PCR is an essential tool in many biological fields, from detecting pathogens to sequencing genes. The key to PCR’s success lies in the design of specific primers and the use of a heat stable DNA polymerase (Taq polymerase), which allows amplification of DNA without degradation during the high-temperature denaturation step.

Answer 1

Polymerase Chain Reaction (PCR) is a molecular biology technique used to amplify specific segments of DNA. It allows researchers to produce millions of copies of a DNA segment from a small sample. PCR has been instrumental in numerous fields, including genetics, diagnostics, and forensic science. The PCR process consists of three main steps, and the ”PCR sequence” refers to the sequence of processes involved in this technique.

The PCR process involves the following steps:

1. Denaturation: In this step, the double-stranded DNA template is heated to about 94–98°C for 20–30 seconds, causing the hydrogen bonds between complementary bases to break and the DNA to denature into two single strands.

2. Annealing: The reaction temperature is lowered to 50–65°C for about 20–40 seconds to allow short DNA primers to attach (anneal) to the complementary sequences at the 3’ ends of the target DNA region. The primers are designed to bind specifically to the target sequence that will be amplified.

3. Extension (Elongation): In this step, the temperature is raised to around 75–80°C, optimal for the DNA polymerase enzyme (usually Taq polymerase) to extend the primers by adding nucleotides to form a new strand of DNA complementary to the original strand. This process continues until the entire target DNA region is copied.

These steps are repeated for 20–40 cycles, doubling the DNA amount with each cycle, resulting in millions of copies of the target DNA sequence. The process is highly specific, as the primers only bind to the regions flanking the target sequence.