Question 1

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

Accepted Answer

Uptake of free DNA from the environment by a competent bacterial cell.

Question 2

A bacterial cell with a chromosomal mutation conferring antibiotic resistance lyses and releases its DNA. Another cell in the environment becomes resistant after taking up this DNA. Which gene transfer mechanism is responsible?

Accepted Answer

Transformation

Question 3

During generalized transduction, which of the following events occurs?

Accepted Answer

A bacteriophage packages random fragments of host DNA and transfers them to a new host.

Question 4

Which structure is essential for the process of bacterial conjugation?

Accepted Answer

Pilus

Question 5

A laboratory experiment involves mixing a plasmid-containing donor cell with a plasmid-free recipient cell. After incubation, the recipient cell acquires antibiotic resistance. Which process most likely occurred?

Accepted Answer

Conjugation

Question 6

Which of the following best explains why only certain bacteria can act as donors in conjugation?

Accepted Answer

They contain the F (fertility) plasmid, which encodes genes for pilus formation.

Question 7

In the context of the F plasmid, what is the function of the tra region?

Accepted Answer

It encodes genes necessary for pilus synthesis and DNA transfer during conjugation.

Question 8

A bacterium is exposed to UV light, causing DNA damage. Later, a bacteriophage infects this cell, packages host DNA, and transfers it to another bacterium. Which gene transfer process is illustrated?

Accepted Answer

Generalized transduction

Question 9

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

Accepted Answer

Conjugation requires direct cell-to-cell contact, while transformation does not.

Question 10

A patient develops a bacterial infection resistant to multiple antibiotics. Genetic analysis reveals the presence of an R plasmid. Which gene transfer mechanism most likely contributed to the spread of resistance?

Accepted Answer

Conjugation

Question 11

Which of the following equations best represents the probability $$P of a $$recipient cell successfully incorporating donor DNA during transformation, given the concentration of free DNA $$[DNA]$$ and a transformation efficiency constant $$k$$?

Accepted Answer

$$P = k \cdot [DNA]$$

Question 12

Which of the following scenarios best illustrates homologous recombination during transformation?

Accepted Answer

A recipient cell integrates a segment of donor DNA into its chromosome at a region of sequence similarity.

Question 13

Which of the following is true regarding Hfr cells in bacterial conjugation?

Accepted Answer

They have the F plasmid integrated into their chromosome.

Question 14

A scientist observes that after conjugation between an Hfr cell and an F- cell, the recipient cell remains F-. What is the most likely explanation?

Accepted Answer

The entire F plasmid was not transferred during conjugation.

Question 15

Which of the following best describes the role of the pilus in DNA uptake by Vibrio species?

Accepted Answer

The pilus binds extracellular DNA and retracts to bring DNA into the periplasm.

Question 16

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

Accepted Answer

Rapid spread of antibiotic resistance among pathogenic bacteria.

Question 17

Which of the following statements about generalized transduction is correct?

Accepted Answer

Any gene from the donor bacterium can be transferred to the recipient.

Question 18

A researcher wants to map the order of genes on a bacterial chromosome using conjugation. Which experimental approach should they use?

Accepted Answer

Measure the time required for different genes to be transferred from an Hfr cell to an F- cell.

Question 19

Which of the following best explains why plasmid-mediated conjugation can rapidly spread antibiotic resistance in a hospital setting?

Accepted Answer

Plasmids can be transferred between different bacterial species via conjugation.

Gene Transfer in Bacteria and Archaea: Mechanisms and Applications

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