PCR Cycle

Question 1

General description of the three stages

Answer 1

1. Desaturation of DNA template
   (~94C to 95C)
2. Annealing (~50C to 60C)
3. Extension/ elongation (~72C)

Question 2

Describe denaturation

Answer 2

• H bonds break;

- target DNA template denatures into ss;

Question 3

Describe annealing

Answer 3

• excess DNA oligonucleotide primers anneal to DNA at opposite ends of target seq;
• complementary base pairing

Question 4

Describe extension

Answer 4

• taq attaches and adds dNTPs to 3’end of primer;

- new strands synthesised in 5’-> 3’ direction; complementary to the template

Question 5

Why PCR is a chain rn?

Answer 5

Newly synthesised DNA strands serve as templates for further DNA synthesis

Question 6

What if the length of the primers are too short?

Answer 6

Hybridise to non-target sites

-> undesired amplification pdts