Question 1

Which of the following best describes the role of licensing factors in eukaryotic DNA replication?

Accepted Answer

They recruit inactive origins to form the pre-replication complex (Pre-RC).

Question 2

A temperature sensitive allele in a bacterial replication protein shows normal growth at 30°C but fails to replicate DNA at 42°C. What does this indicate about the protein?

Accepted Answer

The protein is essential for DNA replication and loses function at non-permissive temperatures.

Question 3

Which stage of DNA replication would be affected by a mutation in a gene encoding a protein exclusively involved in initiation?

Accepted Answer

Only the initiation stage.

Question 4

What is the consequence of removing licensing factors from the nucleus after DNA replication has begun?

Accepted Answer

It blocks replication until the next cell cycle, preventing re-replication.

Question 5

If a mutation affects a protein required for both initiation and elongation of DNA replication, what type of mutant phenotype would you expect?

Accepted Answer

Cell growth stops immediately upon temperature shift.

Question 6

Which of the following statements about temperature sensitive alleles is correct?

Accepted Answer

They allow researchers to study essential genes by shifting between permissive and non-permissive temperatures.

Question 7

A mutation in a gene encoding a component of the replication machinery (elongation) would most likely result in which phenotype?

Accepted Answer

Cell growth stops slowly after temperature shift.

Question 8

Which of the following best explains why there are two distinct stages in eukaryotic DNA replication?

Accepted Answer

To ensure that each origin fires only once per cell cycle.

Question 9

What is the function of the pre-replication complex (Pre-RC) in eukaryotic cells?

Accepted Answer

It marks origins of replication for activation in the next cell cycle.

Question 10

Which of the following would NOT be a likely result of a mutation in a gene encoding a licensing factor?

Accepted Answer

Efficient and accurate DNA synthesis during S phase.

Question 11

A researcher observes that a mutant bacterial strain stops growing immediately after a temperature shift to 42°C. Which stage of DNA replication is most likely affected?

Accepted Answer

Both initiation and elongation stages.

Question 12

Why are temperature sensitive alleles useful for studying essential genes in DNA replication?

Accepted Answer

They enable conditional inactivation, so the phenotype can be observed only under non-permissive conditions.

Question 13

Which of the following is TRUE regarding the firing stage of DNA replication in eukaryotes?

Accepted Answer

It activates the MCM helicase and replication machinery to begin DNA synthesis.

Question 14

If a cell has a mutation in a gene required for the removal of licensing factors after replication, what is the most likely outcome?

Accepted Answer

Origins may be re-licensed and re-fired, leading to re-replication.

Question 15

Which of the following best describes the difference between initiation and elongation mutants in DNA replication?

Accepted Answer

Initiation mutants stop cell growth immediately, while elongation mutants stop slowly.

DNA Replication II: Mechanisms, Regulation, and Mutational Analysis

Study Guide - Practice Questions

Study Guide - Flashcards