Key Area 2: Polymerase Chain Reaction

Question 1

What is polymerase chain reaction?

Answer 1

Polymerase chain reaction ( PCR ) is a technique for amplification of DNA in vitro

Question 2

What temperature are the stands heated to in the first stage?

Answer 2

95 degrees

Question 3

Why is the strand heated to 95 degrees?

Answer 3

It is heated so that the weak hydrogen bonds break and the strands sperate

Question 4

What temperature are the strands cooled to in stage two?

Answer 4

55-60 degrees

Question 5

Why are the strands cooled to 55-60 degrees?

Answer 5

So the hydrogen bonds can form again and allow primers to bind with the strands

Question 6

What temperature are the strands heated to in stage three?

Answer 6

72 degrees

Question 7

Why are the strands heads to 72 degrees?

Answer 7

At this stage, a heat resistant DNA polymerase ( taq polymerase ) begins the replication process on the 3’ end

Question 8

What enzyme is used in PCR?

Answer 8

Heat tolerant DNA polymerase

Question 9

Why must the enzyme used in PCR be heat tolerant?

Answer 9

So that it can withstand the high temperatures of the process