DNA Replication, Mutation, and repair

Question 1

What unwinds DNA to get replicated?

Answer 1

helicase

Question 2

What keeps DNA from supercoiling when getting unwound

Answer 2

topoisomerase

Question 3

What lays down the DNA primers before the Okasaki fragments come in in DNA replication?

Answer 3

DNA primase

Question 4

What makes up the primosome

Answer 4

helicase and DNA Primase

Question 5

Describe DNA polymerase III in prokaryotes?

Answer 5

lays down DNA on both the leading and lagging strand

Question 6

What is the role of DNA polymerase I in prokaryotes?

Answer 6

-Breaks down RNA primer on lagging strand and fills in gap with DNA

Question 7

What joins Okasaki fragments together?

Answer 7

DNA ligase

Question 8

Describe the exonuclease activity of DNA polymerase I in prokaryotes?

Answer 8

• from end of DNA strand
• 3’ to 5’ (1 nucleotide at a time)
• 5’ to 3’ (1-10 nucleotides)

Question 9

Describe the exonuclease activity of DNA polymerase III in prokaryotes?

Answer 9

• from ends of DNA strand

- ONLY 3’ to 5’

Question 10

What are the DNA polymerases in Eukaryotes?

Answer 10

• alpha
• delta
• epsilon
• Beta
• Gamma

Question 11

Describe DNA polymerase alpha?

Answer 11

• makes own primer

- replicates the 1st 20 nucleotides on both leading and lagging

Question 12

Describe DNA polymerase Delta?

Answer 12

-Builds Okazaki fragments on Lagging strand

Question 13

Describe DNA polymerase Epsilon?

Answer 13

-elongates the leading strand

Question 14

Describe DNA polymerase Beta

Answer 14

DNA repair –> Base excision

Question 15

Describe DNA polymerase gamma

Answer 15

-replicate mitochondrial DNA

Question 16

What is Bloom syndrome

Answer 16

• mutation of Helicase

- defect of DNA replication and DNA repair

Question 17

What disorders have defective DOUBLE STRANDED DNA break repair

Answer 17

• Ataxia-Telangiectasia

- also BRCA1 and 2

Question 18

How does UV radiation damage DNA

Answer 18

pyrimidine dimers on SAME strand