Replication of DNA

Question 1

Name the 2 enzymes involved in DNA replication.

Answer 1

DNA polymerase and Ligase

Question 2

What do we call a short strand of nucleotides?

Answer 2

primers

Question 3

To which end of the template strand of DNA do primers bind?

Answer 3

3’ end

Question 4

What is added to the primer by DNA polymerase?

Answer 4

DNA nucleotides

Question 5

To which end of the new strand are nucleotides added?

Answer 5

3’ end

Question 6

What is the very first thing that must happen to the DNA molecule during DNA replication?

Answer 6

unwind the double helix

Question 7

Name the bonds that are broken to separate the two template strands.

Answer 7

hydrogen bonds

Question 8

What name is given to the strand that can be replicated continuously.

Answer 8

leading strand

Question 9

What name is given to the strand that has to be replicated in fragments?

Answer 9

lagging strand

Question 10

Which strand requires DNA polymerase and ligase?

Answer 10

lagging strand

Question 11

What is the role of ligase?

Answer 11

To join the fragments together

Question 12

What does PCR stand for?

Answer 12

Polymerase Chain Reaction

Question 13

What is the purpose of PCR?

Answer 13

To amplify a section of DNA

Question 14

State 3 practical uses of PCR.

Answer 14

solve crimes, paternity suits and diagnose genetic disorders

Question 15

What are the 3 key temperatures you need to remember for PCR?

Answer 15

95, 55, 75

Question 16

What happens when the DNA is heated to 95?

Answer 16

The hydrogen bonds break and the two strands are separated.

Question 17

What happens during PCR when the temperature drops to 55?

Answer 17

The primers bind with their target sequences.

Question 18

During PCR, why is it then heated to 75?

Answer 18

Heat tolerant DNA polymerase replicates the region of DNA by adding nucleotides

Question 19

If you have one strand of DNA at the start, how many will you have at the end of one cycle?

Answer 19

2

Question 20

If you have one strand of DNA at the start, how many will you have at the end of two cycles?

Answer 20

4

Question 21

If you have one strand of DNA at the start, how many will you have at the end of three cycles?

Answer 21

8

Question 22

If you have 100 strands of DNA at the start, how many will you have at the end of one cycle?

Answer 22

200