Question 1

Which of the following best describes the process of bacterial transformation?

Accepted Answer

Uptake of free DNA fragments from the environment by a competent cell

Question 2

Why is recombination necessary when a bacterial cell takes up chromosomal DNA fragments, but not when it takes up a plasmid?

Accepted Answer

Chromosomal DNA fragments cannot replicate independently and must integrate into the host chromosome to be maintained

Question 3

Which enzyme is primarily responsible for mediating homologous recombination in bacteria?

Accepted Answer

RecA

Question 4

A laboratory wants to introduce a plasmid into E. coli cells that are not naturally competent. Which method would be most effective?

Accepted Answer

Electroporation

Question 5

Which of the following statements about R plasmids is FALSE?

Accepted Answer

They require recombination to replicate in a new host

Question 6

During conjugation between an F+ and an F- cell, what is the final result for the recipient cell?

Accepted Answer

It becomes F+

Question 7

Which of the following best explains why Hfr conjugation does NOT usually convert an F- cell into an F+ cell?

Accepted Answer

The entire F factor is rarely transferred before the pilus breaks

Question 8

Which of the following is a function of the tra genes found on the F plasmid?

Accepted Answer

Synthesis of the F pilus for DNA transfer

Question 9

A bacterium is exposed to a short pulse of electricity, allowing DNA to enter the cell. What is this process called?

Accepted Answer

Electroporation

Question 10

Which of the following is NOT a category of plasmids described in E. coli?

Accepted Answer

Lysogenic plasmids

Question 11

Which of the following best describes the role of single-stranded DNA binding proteins (SSB) during transformation?

Accepted Answer

They prevent the single-stranded DNA from re-annealing to its complementary strand

Question 12

Which of the following is a real-world consequence of the spread of R plasmids among bacterial populations?

Accepted Answer

Emergence of multidrug-resistant 'superbugs' in hospitals

Question 13

Which of the following is TRUE regarding the process of rolling circle replication?

Accepted Answer

A single-stranded DNA is displaced and transferred to the recipient cell

Question 14

A bacterium with a virulence plasmid is more likely to:

Accepted Answer

Cause disease due to genes encoding toxins or enzymes

Question 15

Which of the following is a plausible outcome if a bacterium acquires a metabolic plasmid?

Accepted Answer

It gains the ability to degrade new substrates such as toluene

Question 16

Which of the following best describes the difference between natural and artificial transformation?

Accepted Answer

Artificial transformation uses chemical or physical treatments to induce competence

Question 17

Which of the following is a key reason why incompatibility genes are important in plasmid biology?

Accepted Answer

They prevent the uptake of a second plasmid with the same incompatibility group

Question 18

Which of the following is a correct sequence of events during homologous recombination in bacteria?

Accepted Answer

RecA binds to single-stranded DNA, finds homologous sequence, mediates strand exchange

Question 19

Which of the following is NOT a function of bacteriocins encoded by Col plasmids?

Accepted Answer

Increasing the host's ability to degrade lactose

Question 20

Which of the following best explains why recombination is not considered a DNA transfer mechanism?

Accepted Answer

It is a process for integrating foreign DNA into the chromosome, not for moving DNA between cells

Bacterial Recombination and DNA Transfer Mechanisms: Transformation & Conjugation

Study Guide - Practice Questions