Question 1

Which of the following is NOT a reason why bacteria are useful for genetic analysis?

Accepted Answer

They are easy and inexpensive to culture in the laboratory.

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 of the following best describes the process of bacterial conjugation?

Accepted Answer

A donor cell transfers a copy of its DNA to a recipient cell through a pilus.

Question 4

During conjugation, what is the role of the relaxosome at the origin of transfer (oriT)?

Accepted Answer

It binds to oriT and cleaves one strand of the F factor DNA to initiate transfer.

Question 5

Which of the following statements about Hfr strains is TRUE?

Accepted Answer

Hfr strains have the F factor integrated into their chromosome.

Question 6

In an interrupted mating experiment, the order of gene transfer is determined by:

Accepted Answer

The time at which each gene first appears in exconjugants.

Question 7

A bacterium that has received a segment of donor DNA via transformation and incorporated it into its chromosome is called a:

Accepted Answer

Transformant

Question 8

Which of the following best describes generalized transduction?

Accepted Answer

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

Question 9

In cotransduction mapping, which of the following is TRUE?

Accepted Answer

Genes that are closer together are more likely to be cotransduced.

Question 10

Which of the following is a key feature of lateral gene transfer (LGT) in bacteria?

Accepted Answer

LGT can introduce genes from distantly related species, often identified as genomic islands.

Question 11

A partial diploid (merodiploid) bacterial cell is produced when:

Accepted Answer

A recipient cell receives a complete F' plasmid carrying bacterial genes.

Question 12

Which of the following equations correctly represents the frequency of cotransduction for two genes, A and B, given the number of cotransductants (N_{AB}) and the total number of transductants (N_{total})?

Accepted Answer

$$f_{cotransduction} = \frac{N_{AB}}{N_{total}}$$

Question 13

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 14

During the lytic cycle of a bacteriophage, which of the following events occurs LAST?

Accepted Answer

Lysis of the host cell and release of progeny phage particles.

Question 15

Which of the following best explains why multiple Hfr strains are needed to construct a complete genetic map of E. coli?

Accepted Answer

Each Hfr strain transfers genes in only one direction from its unique integration site.

Question 16

A researcher observes that two genes are cotransformed at a high frequency. What does this suggest about their physical relationship on the chromosome?

Accepted Answer

They are located close together on the chromosome.

Question 17

Which of the following is a characteristic of high-copy-number plasmids?

Accepted Answer

They replicate independently of the bacterial chromosome and can be present in many copies per cell.

Question 18

In a conjugation experiment, an F+ donor is mixed with an F− recipient. After conjugation, which of the following outcomes is expected?

Accepted Answer

Both cells become F+.

Question 19

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

Accepted Answer

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

Question 20

A bacterial cell is found to contain a genomic island with a G-C content much higher than the rest of its genome. What is the most likely explanation for this observation?

Accepted Answer

The region was acquired by lateral gene transfer from a distantly related species.

Genetic Analysis and Mapping in Bacteria and Bacteriophages: Study Notes

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