Question 1

Which of the following best explains why bacteria are ideal organisms for genetic analysis and mapping?

Accepted Answer

They have haploid genomes, short generation times, and produce large numbers of progeny.

Question 2

A bacterial strain that can grow on minimal medium but not on medium lacking leucine is best described as:

Accepted Answer

An auxotroph for leucine

Question 3

Which process involves the direct transfer of DNA from a donor to a recipient cell via a pilus?

Accepted Answer

Conjugation

Question 4

What is the primary function of the F (fertility) plasmid in E. coli?

Accepted Answer

To promote its own transfer from donor to recipient cells

Question 5

During rolling circle replication in bacterial conjugation, which strand is transferred to the recipient cell?

Accepted Answer

The T (transfer) strand

Question 6

In an interrupted mating experiment, the time at which a gene first appears in exconjugants is most closely related to:

Accepted Answer

The gene's distance from the origin of transfer (oriT)

Question 7

Which of the following best describes an Hfr cell?

Accepted Answer

A cell with the F factor integrated into its chromosome

Question 8

A partial diploid (merodiploid) in bacteria is produced when:

Accepted Answer

A recipient cell receives an F' plasmid carrying bacterial genes

Question 9

Which of the following is a key difference between generalized and specialized transduction?

Accepted Answer

Generalized transduction can transfer any bacterial gene, while specialized transduction transfers only genes adjacent to the prophage integration site.

Question 10

Which equation best represents the relationship between cotransduction frequency ($$f) $$and the distance ($$d) $$between two genes?

Accepted Answer

$$f \propto \frac{1}{d}$$

Question 11

A researcher observes that a region of a bacterial genome has a GC content significantly different from the rest of the genome and is highly similar to genes in a distantly related species. What is the most likely explanation?

Accepted Answer

The region is a result of lateral gene transfer (LGT).

Question 12

Which of the following best describes the process of transformation in bacteria?

Accepted Answer

Uptake of naked DNA from the environment by a competent cell

Question 13

In a conjugation experiment, donor cells are sensitive to streptomycin and recipients are resistant. After mating, cells are plated on medium containing streptomycin. Which cells will grow?

Accepted Answer

Only recipient and exconjugant cells

Question 14

Which of the following is NOT a typical feature of a genomic island acquired by lateral gene transfer?

Accepted Answer

It is always smaller than 1 kb.

Question 15

Which step is unique to the lysogenic cycle of a temperate bacteriophage?

Accepted Answer

Integration of the phage chromosome into the host genome

Question 16

A bacterium is described as 'competent.' What does this mean in the context of genetic analysis?

Accepted Answer

It can take up DNA from its environment during transformation.

Question 17

Which of the following statements about F' (F prime) plasmids is correct?

Accepted Answer

They result from imperfect excision of the F factor from the Hfr chromosome, carrying some bacterial genes.

Question 18

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

Accepted Answer

Rapid spread of antibiotic resistance among pathogenic bacteria

Question 19

In a cotransformation experiment, two genes are frequently cotransformed. What does this suggest about their physical relationship?

Accepted Answer

They are closely linked on the chromosome.

Question 20

Which of the following best describes the outcome of an Hfr × F− mating?

Accepted Answer

The recipient may acquire donor genes but does not become a donor cell.

Genetic Analysis and Mapping in Bacteria and Bacteriophages – Study Notes

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