Question 1

Which of the following statements best describes bacterial conjugation?

Accepted Answer

It requires two active bacterial cells, with gene transfer occurring in one direction via a pilus.

Question 2

During bacterial conjugation, what is the primary function of the pilus?

Accepted Answer

To connect two bacterial cells and facilitate the transfer of genetic material.

Question 3

Which gene transfer mechanism is most likely to result in the spread of antibiotic resistance among bacteria in a hospital setting?

Accepted Answer

Conjugation, where plasmids carrying resistance genes are transferred via a pilus.

Question 4

What distinguishes an HFR cell from an F+ cell in bacterial conjugation?

Accepted Answer

An HFR cell has the F-plasmid integrated into its chromosome, while an F+ cell has the F-plasmid as a separate, cytoplasmic element.

Question 5

Which of the following best explains why conjugation is not considered sexual reproduction in bacteria?

Accepted Answer

Because the cells do not fuse and only a portion of genetic material is transferred in one direction.

Question 6

A donor cell with an F-plasmid (F+) transfers genetic material to a recipient cell (F-). After conjugation, what is the genotype of the recipient cell?

Accepted Answer

F+

Question 7

Which of the following is a consequence of plasmid transfer via conjugation?

Accepted Answer

The recipient cell gains new genetic traits, such as antibiotic resistance, depending on the plasmid's genes.

Question 8

In the process of rolling circle replication during conjugation, what happens to the plasmid DNA?

Accepted Answer

One strand of the plasmid is nicked and transferred, while the complementary strand is synthesized in the recipient cell.

Question 9

Which of the following equations best represents the increase in antibiotic-resistant cells after conjugation, assuming $$N$$ susceptible cells and $$M$$ resistant donor cells, and each donor transfers resistance to one recipient?

Accepted Answer

$$N_{resistant} = M 	imes 2$$

Question 10

Which gene transfer mechanism involves the uptake of free DNA from the environment by a bacterial cell?

Accepted Answer

Transformation

Question 11

A bacterial cell receives a linear fragment of DNA from an HFR cell during conjugation. What must occur for this fragment to be stably maintained in the recipient cell?

Accepted Answer

The fragment must integrate into the recipient's chromosome via homologous recombination.

Question 12

Which of the following is NOT a requirement for conjugation to occur between two bacterial cells?

Accepted Answer

A viral intermediate to mediate DNA transfer.

Question 13

Which of the following best describes the role of IS elements in the integration of the F-plasmid into the bacterial chromosome?

Accepted Answer

IS elements provide homologous sequences that facilitate recombination between the plasmid and chromosome.

Question 14

Which of the following scenarios would most likely result in a recipient cell remaining F- after conjugation with an HFR cell?

Accepted Answer

The recipient cell receives only a fragment of the integrated F-plasmid and not the entire plasmid.

Question 15

Which of the following is a key difference between transformation and conjugation in bacteria?

Accepted Answer

Conjugation requires direct cell-to-cell contact, while transformation involves uptake of free DNA.

Question 16

Which of the following best explains why plasmid transfer via conjugation is a powerful mechanism for the spread of antibiotic resistance?

Accepted Answer

Plasmids can carry resistance genes and be rapidly transferred between bacteria, allowing recipients to survive antibiotic treatment.

Question 17

Which of the following is true regarding the directionality of gene transfer during bacterial conjugation?

Accepted Answer

Gene transfer occurs unidirectionally from donor to recipient.

Question 18

A bacterial cell with a resistance plasmid shares it with a susceptible cell via conjugation. If the resistance gene is expressed, what is the likely outcome?

Accepted Answer

The recipient cell becomes resistant to the antibiotic.

Question 19

Which of the following best describes the process of homologous recombination in the integration of plasmid DNA into the bacterial chromosome?

Accepted Answer

Homologous recombination occurs at regions of sequence similarity, such as IS elements, allowing plasmid DNA to integrate into the chromosome.

Question 20

Which of the following is a real-world consequence of gene transfer via conjugation in bacteria?

Accepted Answer

Rapid spread of antibiotic resistance among pathogenic bacteria, complicating treatment of infections.

Microbial Gene Transfer: Mechanisms and Consequences

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