dna replication

Question 1

List the requirements for DNA replication.

Answer 1

1. Template DNA 2. dNTPs (dATP, dGTP, dCTP, dTTP) 3. Primer (RNA/DNA) 4. Enzymes (DNA Pol, Helicase, etc.) 5. Mg²⁺

Question 2

Name the key enzymes/proteins in DNA replication.

Answer 2

Helicase, SSBPs, Topoisomerase, Primase, DNA Polymerase, Ligase

Question 3

What happens during initiation?

Answer 3

Origin recognition (OriC in prokaryotes, ORC in eukaryotes), Helicase unwinds DNA, Primase adds RNA primer

Question 4

What occurs in elongation?

Answer 4

DNA Pol adds dNTPs 5’→3’, Leading strand: continuous, Lagging strand: Okazaki fragments

Question 5

How does termination differ in prokaryotes vs eukaryotes?

Answer 5

Prokaryotes: Ter sites + Tus proteins. Eukaryotes: Telomerase extends telomeres

Question 6

What are DNA polymerase’s two key functions?

Answer 6

1. 5’→3’ polymerization 2. 3’→5’ exonuclease proofreading

Question 7

What does DNA helicase do?

Answer 7

Unwinds DNA at replication fork using ATP

Question 8

What is DNA ligase’s role?

Answer 8

Seals nicks in Okazaki fragments with phosphodiester bonds

Question 9

How do prokaryotic and eukaryotic genomes differ?

Answer 9

Prokaryotes: Circular, single origin (OriC). Eukaryotes: Linear, multiple origins, telomeres

Question 10

What prevents supercoiling during replication?

Answer 10

Topoisomerase (DNA gyrase in prokaryotes)

Question 11

What replaces RNA primers in eukaryotes?

Answer 11

DNA Pol δ/ε + FEN1 remove flaps, Ligase seals

Question 12

What is the function of single-strand binding proteins (SSBPs)?

Answer 12

Prevent reannealing of unwound DNA