1. Basic PCR Procedure:

The basic PCR procedure includes 3 steps that are repeated 20 - 30 times. The process consists of: 1) denaturing: heating the double stranded DNA (to 90-95 C) to separate the strands, 2) annealing: lowering the temperature to allow primers to bind single stranded DNA, 3) elongation: the DNA polymerase adds nucleotides to the growing strand.

2. Why is Taq DNA polymerase used?

Taq DNA polymerase was isolated from Thermus aquaticus - a thermophilic bacterium. The enzyme is thermostable - even at temperatures over 90 C. The enzyme's ability to withstand the elevated temeratures required for denaturing steps during thermal cycling makes it well suited for the task. The purpose of the enzyme is to extend a DNA primer, using a DNA template.

3. What are PCR primers?

Primers are short synthesized DNA strands - typically 18-25 bp. They are designed to complement the nucleotides on the template DNA at the starting and ending points of the DNA fragment to be synthesized. Primer design is a complex process that involves taking into consideration the melting temperatures and, therefore G-C content. Read more about primer design.