Question 1

Which of the following is a key advantage of using *Escherichia coli* for genetic studies compared to *Homo sapiens* and *Drosophila melanogaster*?

Accepted Answer

It has a haploid genome and short generation time, enabling rapid and cost-effective study of rare genetic events.

Question 2

A bacterium that cannot synthesize proline and cannot grow on minimal medium unless proline is added is best described as:

Accepted Answer

An auxotroph

Question 3

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

Accepted Answer

A donor cell with an F plasmid transfers DNA to a recipient cell via a conjugation pilus.

Question 4

What is the primary difference between an F+ cell and an Hfr cell?

Accepted Answer

Hfr cells have the F plasmid integrated into their chromosome, allowing for transfer of chromosomal genes during conjugation.

Question 5

During time-of-entry mapping with Hfr cells, which gene will be transferred first to the recipient cell?

Accepted Answer

The gene closest to the origin of transfer (oriT) on the Hfr chromosome.

Question 6

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

Accepted Answer

F' plasmids can carry bacterial chromosomal genes, creating partial diploids when transferred to another cell.

Question 7

A bacterium is able to grow on minimal medium with lactose but not on minimal medium with glucose. What is the most likely genotype?

Accepted Answer

lac- pro-

Question 8

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

Accepted Answer

Uptake of free DNA from the environment by a competent cell, followed by homologous recombination.

Question 9

Which of the following is true regarding the outcome of conjugation between an Hfr cell and an F- cell?

Accepted Answer

The recipient cell remains F- but may acquire donor chromosomal genes.

Question 10

In the context of lateral gene transfer, what is the main role of homologous recombination?

Accepted Answer

To integrate donor DNA into the recipient's chromosome.

Question 11

Which of the following best explains why bacteria are ideal for studying statistically rare genetic events?

Accepted Answer

They produce billions of progeny in a short time, allowing rare events to be detected.

Question 12

Which of the following is NOT a requirement for bacterial transformation?

Accepted Answer

A conjugation pilus.

Question 13

During transduction, what is the role of the bacteriophage?

Accepted Answer

It packages host DNA fragments and injects them into a new recipient cell.

Question 14

Which of the following best describes cotransduction frequency?

Accepted Answer

The frequency at which two genes are transferred together by a transducing phage, used to map gene distance.

Question 15

A researcher wants to select for exconjugants that have received both donor and recipient-specific DNA after Hfr conjugation. Which method should they use?

Accepted Answer

Select for growth on media requiring both donor and recipient markers.

Question 16

Which of the following equations best represents the calculation of cotransduction frequency?

Accepted Answer

$$f = \frac{	ext{Number of cotransductants}}{	ext{Total number of transductants}}$$

Question 17

Which of the following is a correct statement about the lytic and lysogenic cycles of bacteriophages?

Accepted Answer

In the lytic cycle, the phage replicates and lyses the host cell, while in the lysogenic cycle, the phage DNA integrates into the host genome and can be dormant.

Question 18

A bacterium with the genotype pro- lac+ strR is plated on minimal medium with lactose and streptomycin. Which of the following best describes its growth?

Accepted Answer

It will not grow because it cannot synthesize proline.

Question 19

Which of the following is a direct result of rolling circle replication during bacterial conjugation?

Accepted Answer

A single-stranded DNA is transferred from the donor to the recipient cell.

Genetic Analysis and Mapping in Bacteria and Bacteriophages (Ch. 6) - Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard