Polymerase Chain Reaction

Question 1

What is the purpose of PCR

Answer 1

A process used to artificially multiply a chosen
piece of genetic material.

May also be known as DNA amplification.

One strand of DNA may yield 2^30 strands or
more.

Question 2

How does it work? Briefly describe the process.

Answer 2

One cycle:

1. Double-stranded DNA is
   denatured using heat (95°C) to
   separate strands by breaking
   hydrogen bonds
2. Temperature is lowered (55-60°C)
   which allows the primers to anneal
3. Temperature raised (72°C) and
   Taq polymerase adds nucleotides in
   the 5’–> 3’ to synthesize the new
   DNA strand

Repeat cycle (steps 1-3)

Question 3

Reason for using taq polymerase

Answer 3

Taq polymerase is used because it can withstand high temperatures (won’t denature), making it ideal for the DNA amplification process in PCR (Polymerase Chain Reaction). Unlike human polymerase which would denature under high temperatures.