Topic 2: Replication of DNA

Question 1

What to DNA prior to cell division?

Answer 1

DNA is replicated by a DNA polymerase

Question 2

What does DNA polymerase need to start replication?

Answer 2

DNA polymerase needs PRIMERS to start replication

Question 3

What are primers?

Answer 3

Short strands of nucleotides (RNA)

Question 4

What carbon end of the DNA template to primer is bound to?

Answer 4

Primers bind to the 3’ end of the DNA template

Question 5

What is the purpose of a primer?

Answer 5

Primers allow polymerase to our DNA nucleotides using complimentary base pairing

Question 6

What are new DNA strands made from?

Answer 6

DNA nucleotides

Question 7

What happens to DNA when it is unwound?

Answer 7

Hydrogen bonds between the bases are broken to form 2 template strands

Question 8

What is the limitation of DNA polymerase and adding nucleotides?

Answer 8

DNA polymerase can only add DNA nucleotides in 1 DIRECTION

Question 9

Why is one new strand known as the leading strand?

Answer 9

Because it is replicated continuously - its replication is occurring in the same direction as the DNA is unwinding

Question 10

Why is the other strand known as the lagging strand?

Answer 10

Because it is replicated in fragments - it’s replication is occurring in the opposite direction to the unwinding of the DNA so requires repeated addition of primer is as new sections of the template strand are exposed

Question 11

What is the function of ligase in DNA replication?

Answer 11

Joins the fragments of DNA together on the lagging strand by forming a covalent bond between the 5’ and 3’ end of the strands