DNA Replication- Lecture

Question 1

List the 3 models of DNA replication and tell which one is correct

Answer 1

Semiconservative replication
Conservative
Dispersive

Question 2

What are the 2 general steps involved in DNA replication?

Answer 2

1) Helix is unwound

2) Add nucleotides

Question 3

What direction is DNA synthesized? Read?

Answer 3

5’ to 3’

3’ to 5’

Question 4

Where does DNA replication begin?

Answer 4

Origin of replication

Question 5

Explains what happens in both Prokaryotes and Eukaryotes at the origin of replication

Answer 5

Prokaryotes- 1 OR opens and replication bubbles form on side, 2 forks move away and meet on other side

Eukaryotes- multiple ORs open and create bubbles, linear not circular, forks move away and then fuse

Question 6

Replication is initiated with what after what happens?

Answer 6

Primer- DNA helicase unwinds at OR

Question 7

What does RNA primase do?

Answer 7

Lays down 5-10 nucleotide template for DNA polymerase to recognize (at 3’ end)

Question 8

What is the job of DNA polymerase after the RNA primer adds a nucleotide template?

Answer 8

Adds nucleotides

Question 9

What is the job of helicase?

Answer 9

Separates strands of DNA (unwinds)

Question 10

What is the job of topoisomerase?

Answer 10

Stops DNA molecules from breaking (prevents strain)

Question 11

What prevents the strands from joining?

Answer 11

Single stranded binding proteins

Question 12

How are nucleotides added to the new strand?

Answer 12

• Nucleoside triphosphate added after condensation reaction

- DNA polymerase

Question 13

Where can DNA polymerase only add to?

Answer 13

3’ end

Question 14

What work towards the replication fork reading backwards?

Answer 14

Okazaki fragments

Question 15

What seals DNA between Okazaki fragments

Answer 15

DNA ligase

Question 16

What increases the efficiency of DNA polymerization?

Answer 16

Sliding DNA clamp