Question 1

Which of the following is required for the initiation of DNA replication at the bacterial oriC site?

Accepted Answer

The oriC region must be fully methylated on both DNA strands.

Question 2

In E. coli, which protein acts as a licensing factor by binding to short repeated sequences at oriC and facilitating DNA melting?

Accepted Answer

DnaA-ATP

Question 3

What is the function of DnaB helicase during bacterial DNA replication?

Accepted Answer

It unwinds the DNA double helix at the replication fork.

Question 4

Which of the following best describes the minimal origin of replication in E. coli?

Accepted Answer

It is defined by the distance between the outside members of the 13-mer and 9-mer repeats.

Question 5

During eukaryotic DNA replication, which complex is responsible for recognizing the origin of replication and binding throughout most of the cell cycle?

Accepted Answer

Origin Recognition Complex (ORC)

Question 6

In eukaryotes, what is the role of licensing factors such as Cdc6 and Cdt1 during DNA replication?

Accepted Answer

They recruit inactive MCM helicase to origins, forming the pre-replication complex.

Question 7

Which statement about the timing of eukaryotic DNA replication is correct?

Accepted Answer

Replicons near one another tend to be activated at similar times during S phase.

Question 8

A temperature-sensitive mutant in a bacterial DNA replication protein shows immediate cessation of cell growth when shifted to a non-permissive temperature. Which stage of replication is most likely affected?

Accepted Answer

Elongation (DNA synthesis)

Question 9

Which of the following equations correctly represents the formation of a phosphodiester bond during DNA polymerization?

Accepted Answer

$dNTP + (DNA)_{n} \rightarrow (DNA)_{n+1} + PP_i$

Question 10

Which feature distinguishes DNA polymerases involved in genome replication from those involved in DNA repair?

Accepted Answer

Genome replication polymerases have higher fidelity and proofreading activity.

Question 11

In yeast, which ARS domain contains the consensus sequence essential for replication origin function?

Accepted Answer

Domain A

Question 12

Which of the following best explains why newly synthesized bacterial DNA cannot be immediately replicated again?

Accepted Answer

It is not fully methylated, preventing origin recognition and re-initiation.

Question 13

Which protein complex is responsible for melting the AT-rich region at the bacterial origin of replication?

Accepted Answer

DnaA-ATP oligomeric complex

Question 14

A mutation in a protein exclusively involved in the initiation stage of DNA replication would most likely result in which phenotype?

Accepted Answer

Cell growth stops slowly after temperature shift.

Question 15

Which of the following statements about the eukaryotic pre-replication complex (pre-RC) is correct?

Accepted Answer

It is formed during licensing and is converted to the pre-initiation complex by activating factors.

Question 16

Which of the following is a cis-acting element in DNA replication?

Accepted Answer

OriC in bacteria

Question 17

Which domain of DNA polymerase contains the catalytic active site for phosphodiester bond formation?

Accepted Answer

Palm domain

Question 18

Which of the following best describes the processivity of DNA polymerase?

Accepted Answer

The ability of the enzyme to synthesize long stretches of DNA without dissociating from the template.

Question 19

Which of the following equations represents the conversion of ATP to ADP during the inactivation of a licensing factor?

Accepted Answer

$ATP \rightarrow ADP + P_i$

DNA Replication: Initiation, Regulation, and Enzymology

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