Molecular Techniques To Study Gene Expression

Question 1

[PCR] What does PCR stand for?

Answer 1

Polymerase Chain Reaction.

Question 2

[PCR] What is PCR?

Answer 2

PCR is an in-vitro technique to amplify a specific sequence of DNA.

Question 3

[PCR] List the steps of PCR.

Answer 3

• Denaturation
• Annealing
• Elongation

Question 4

[PCR] What is the temperature required in the Denaturation step?

Answer 4

95°C

Question 5

[PCR] What is temperature required in Annealing step?

Answer 5

54-68°C

Question 6

[PCR] What is the temperature required in Elongation step?

Answer 6

72°C

Question 7

[PCR] What is the purpose of the Denaturation step?

Answer 7

1. To break hydrogen bonds holding the double-stranded DNA together to form 2 single-stranded DNA.
2. Each strand acts as a template for sythesis of complementary strand.

Question 8

[PCR] What is the purpose of the Annealing step?

Answer 8

To allow DNA primers in the PCR mixture to anneal to DNA template.

Question 9

[PCR] Name the primers present in the Annealing step.

Answer 9

Forward and reverse primers.

Question 10

[PCR] What is the purpose of the DNA primers?

Answer 10

1. They bind to the DNA sequences flanking opposite ends of the target DNA sequence that is to be amplified.
2. They also provide the free 3’OH for the DNA polymerase to add new dNTPs (deoxyribonucleotides) for elongation.