The DNA polymerase used must be thermostable.

  Taq polymerase was discovered and purified in 1976. 10 years later, the process of the PCR was developed using this thermostable DNA polymerase.
Kary Mullins received the Nobel Prize
in 1993 for his role in developing this process. 

            PCR process (one cycle)

Covid-19 diagnostics

4. Primers: PCR primers are approximately 15–30 bases and serve as a starting point for DNA synthesis. There are 2 primers for every PCR reaction. One anneals to the 3'-5' strand and one anneals to the 5'-3' strand. In this way they flank the region of DNA that is being copied.

DNA is heated to separate the strands and then DNA polymerase creates new strands.

 Taq Polymerase is that
​thermostable DNA polymerase

    Taq Polymerase is a DNA polymerase named after the thermophilic bacterium in which it was found. These bacterium live in hot springs
and have the species name
​ Thermus aquaticus = Taq.

2. Taq polymerase

1. DNA sample

PCR exhibits exponential  amplification...
2 becomes 4
4 becomes 8
8 becomes 16...
30 cycles synthesizes
> a billion copies
of the original sample

5. buffer: PCR buffer provides a healthy  environment for the Taq polymerase. The buffer pH is usually between 8.0 and 9.5 and contains K+ which promotes primer annealing

                   PCR components                

Applications for PCR... 

 The Polymerase Chain Reaction (PCR) is a technique used to make millions of copies of DNA in just hours. 
It was developed by Kary Mullis in 1983.

       The Polymerase Chain Reaction (PCR)

3. Nucleotides: also called deoxynucleotide triphosphates (dNTPs), are the building block monomers that make up the DNA polymer.  They lose two of their phosphate groups when incorporated into DNA during replication. The triphosphate group contains high-energy bonds which release energy when broken which the DNA polymerase uses to synthesize complementary DNA strands.