Polymerase Chain Reaction

Question 1

What is PCR?

Answer 1

• Polymerase Chain Reaction
• Making multiple copies of the DNA used for analysis

Question 2

What are the main ‘ingredients’ needed for PCR?

Answer 2

• original DNA sample
• nucleotides bases (4)
• primers
• DNA polymerase

Question 3

STEP ONE - What is the denaturing phase?

Answer 3

• temperature inside the machine 90-95 degree Celsius
• breaks the hydrogen bonds between the 2 DNA strands, separating them

Question 4

STEP TWO - what is the annealing phase?

Answer 4

• Temperature is 50-55 degree Celsius
• Primers anneal to join both ends of the single DNA strands
• These are short single - stranded sections of DNA, complementary to the end of the strands, needed for replication to start

Question 5

STEP THREE - What is the extension phase?

Answer 5

• Temperature is 70-75 degree Celsius
• This is the optimum temperature for the chosen DNA polymerase enzyme to work
  -This adds the bases to the primers, extending the complementary strands
• This results in the double stranded DNA genetically identical to the original sample.

Question 6

What is the machine called used for PCR?

Answer 6

• Thermal cycler

Question 7

What is the enzyme used?

Answer 7

• Taq polymerase

Question 8

What does Taq polymerase do?

Answer 8

• It comes from the thermophillic hot spring bacteria.
• It is not denatured by high temperatures needed inside the PCR machine