Replication

Question 1

Replication

Answer 1

synthesis of DNA from DNA

Question 2

What direction doe the DNA strand read?

Answer 2

5’-3’

Question 3

In replication, there is one old strand and one new strand, this is said to be

Answer 3

semi-conservative

Question 4

What enzyme unwinds the DNA helix and separates the strands, forming the replication fork at the origin?

Answer 4

DNA helicase

Question 5

How do the exposed strands stay stable after they unwind from the opposite strand?

Answer 5

single stranded binding proteins

Question 6

In what direction does DNA polymerase synthesize DNA?

Answer 6

5’-3’

Question 7

What does DNA polymerase need in order to start synthesizing?

Answer 7

RNA primase

Question 8

Leading strand

Answer 8

The strand that synthesizes away from the origin of the replication fork. continuous replication

Question 9

Lagging strand

Answer 9

the strand that replicates in the direction of the replication fork. discontinuous replication

Question 10

Okazaki Fragments

Answer 10

The lagging strand has to keep being synthesized in fragments because it is going towards the replication fork and needs to keep going back.

Question 11

What replaces the primer?

Answer 11

DNA polymerase 1

Question 12

What seals up the phosphodiester backbone?

Answer 12

DNA ligase

Question 13

What does topoisomerase do?

Answer 13

releaves tension of twist as it unwinds by cutting the backbone and resealing it.

Question 14

What happens when there is not enough room to lay prime on 5’ end of lagging strand?

Answer 14

telomerase will take 3’ end of 5’-3’ and extend so that daughter strand an keep laying down primer and don’t loose and genetic material

Question 15

What is the energy for replication?

Answer 15

nucleosidetriphosphates

Question 16

DNA polymerase I

Answer 16

slow. replaces primers. 3’-5’ exonuclease activity if there’s a mistake (Proofreading). 5’-3’ exonuclease activity to take off primer

Question 17

DNA polymerase III

Answer 17

Bulk of work. fast. 3’-5’ exonuclease activity if there is a mistake (proofreading)

Question 18

Means of DNA repair

Answer 18

Proofreading, Nick translation (DNA pol I), Mismatch repair, base excision repair, nucleotide excision repair

Question 19

nick translation

Answer 19

DNA pol I. Pulls off mistake as it’s replicating

Question 20

Mismatch repair

Answer 20

Methylate the parent, recognize that the daughter is mistake, will cut out several daughter nucleotides. DNA pol III comes in a fixes it. Ligase seals backbone

Question 21

Base excision repair

Answer 21

Exonuclease cuts the base off. DNA Pol I will fill in gap and Ligase will seal backbone.

Question 22

nucleotide excision repair

Answer 22

Ex. UV light damage