Polymerase Chain Reactions

Question 1

Why do researchers use PCRS?

Answer 1

To amplify single copies of DNA to billions of identical copies.

Question 2

What section of DNA is amplified?

Answer 2

Only a small, single, target section is amplified.

Question 3

What is the formula for how many copies of target DNA you get?

Answer 3

2^n where n is the number of cycles.

Question 4

Why is the target section chosen?

Answer 4

It is highly variable.

Question 5

What is the point of using target DNA?

Answer 5

If we look at the introns of these sections, any one person should have a different pattern.

Question 6

What is the procedure of PCR?

Answer 6

Start with sample of DNA:
1. Add primers
2. Add Nucleotides
3. Add taq polymerase
Then heat to 95, 60, then 72.

Question 7

What are primers?

Answer 7

Short (20 nucleotide) pieces of DNA of known sequence that will bond to both the leading and lagging strands.

Question 8

Which strands do the primers bond to?

Answer 8

Lagging and leading

Question 9

What are nucleotides?

Answer 9

Basix building blocks of DNA

Question 10

What is taq polymerase?

Answer 10

Enzyme from thermophilic bacteria that lives in hot springs. It is adapted to warm temperatures.

Question 11

Explain the heating cycles specifically.

Answer 11

Heating to 95: DNA is denatured (H-bonds broken)
Cooling to 60: Allows primers to anneal to complementary sequences on strands.
Heating to 72: Allows taq polymerase to function optimally on DNA and add complementary bases.

Question 12

What happens after the heating cycle?

Answer 12

The DNA pieces are separated based on size to establish the unique identity of the sample.