Replication Of DNA

Question 1

Prior to cell division, how is DNA replicated?

Answer 1

Replicated by DNA polymerase

Question 2

To begin DNA replication, what happens to the DNA?

Answer 2

DNA is unwound and hydrogen bonds between bases are broken to form two template strands

Question 3

What is a primer?

Answer 3

A primer is a short strand of nucleotides that is needed to start replication

Question 4

Where does the primer bind to on the template DNA strand?

Answer 4

3’ end

Question 5

What does the binding of the primer allow?

Answer 5

Allows polymerase to add nucleotides

Question 6

What does DNA polymerase do?

Answer 6

Adds DNA nucleotides, using complementary base pairing to the deoxyribose 3’ end of the new DNA strand which is forming

Question 7

DNA polymerase can only add DNA nucleotides in … direction

Answer 7

One direction

Question 8

The leading strand is replicated…

Answer 8

Continuously

Question 9

The lagging strand is replicated in…

Answer 9

Fragments

Question 10

How are fragments of DNA joined together?

Answer 10

Ligase

Question 11

PCR amplifies DNA how?

Answer 11

Using complementary primers for specific target sequences

Question 12

In PCR, primers are complementary to specific target sequences at the two ends of?

Answer 12

The region of DNA being amplified

Question 13

What does repeated cycles of heating and cooling achieve?

Answer 13

Used to achieve amplification

Question 14

DNA is heated to 92-98 why?

Answer 14

To separate strands of DNA

Question 15

DNA is then cooled to 50-65 why?

Answer 15

To allow primers to bind to target sequences

Question 16

DNA is then heated to 70-80 why?

Answer 16

Heat-tolerant DNA polymerase to replicate the region of DNA

Question 17

Why is the DNA heat-tolerant?

Answer 17

So it doesn’t denature, and can work in the changing conditions

Question 18

What is practical applications of PCR? Give examples;

Answer 18

Amplifying DNA to help solve crimes
Settle paternity suits
Diagnose genetic disorders