Mod2 - DNA Replication

Question 1

Which direction does DNA replication occur (relative to the new strand)?

Answer 1

5’ to 3’ direction

Question 2

What is the name of the short section of nucleic acid (DNA or RNA) which is needed to allow the polymerase to synthesise the new DNA?

Answer 2

Primer

Question 3

Compare DNA Polymerase I and III (in terms of main function, and exonuclease activity in each direction)

Answer 3

I: 3’->5’ AND 5’->3’, DNA Repair, Replication
II: 3’->5’ but NOT 5’->3’, Main Replicating Enzyme

Question 4

Compare DNA Polymerase alpha vs delta (in terms of main function, and exonuclease activity in each direction)

Answer 4

alpha: neither 3’->5’ nor 5’->3’, Priming during Replication
delta: 3’->5’ but NOT 5’->3’, Main Replicative Enzyme

Question 5

In what type of cells are the 4 given examples of DNA polymerases found?

Answer 5

DNA Polymerase I and III = bacteria
DNA Polymerases alpha and delta = eukaryotes

Question 6

At the replication fork, what prevents the two strands from re-attaching to each other?

Answer 6

Single-stranded binding proteins (SSBs)

Question 7

What two roles do SSBs have?

Answer 7

Single-stranded binding proteins prevent the two strands of DNA from reattaching, and also protect them from being attacked by nucleases

Question 8

What do the different patterns of DNA Replication seen in S phase relate to? (Also name the two relevant categories of DNA)

Answer 8

The type of DNA being replicated (Euchromatin replicated first, then Heterochromatin)

Question 9

What would be the name of a DNA nucleotide containing Adenine (acronym AND full name)?

Answer 9

DATP (2’-deoxyadenosine 5’-triphosphate)