PCR

Question 1

Step one

Heating to 95°C

Answer 1

Denature the template DNA

Separate DNA into single strands

Question 2

Step Two

Cool to 50°C - 65°C

Answer 2

Anneal the primers (add primers)

Allows base pairs to anneal to their complimentary sequences

Primers designed to bracket DNA region

Question 3

Step Three

Heat to 72°C

Answer 3

Extended – add base and make new strands

Allows Taq 1 DNA polymerase to attach at each priming site and synthesise a new DNA strand

Question 4

What is PCR?

Answer 4

Polymerase chain reaction

PCR method of increasing the amount of DNA in a sample by using amplification

Process carried out in ‘thermal cycler’

The DNA sequence to be copied is mixed with primers, DNA fragments, free nucleotide bases and Taq 1 polymerase

Heated to 95°C to separate two DNA strands

Question 5

Limitations of PCR

Answer 5

Need to know primer sequence

Only short sequences can be amplified

You only obtain the DNA fragment (need to clone it afterwards)