Question 1

Which of the following best describes the main structural difference between prokaryotic and eukaryotic cells?

Accepted Answer

Prokaryotic cells lack membrane-bound organelles, while eukaryotic cells possess them.

Question 2

Which of the following statements about bacterial growth phases is correct?

Accepted Answer

The stationary phase is characterized by a balance between cell division and cell death.

Question 3

A bacterium that can synthesize all essential organic compounds and grow on minimal medium is called a:

Accepted Answer

Prototroph

Question 4

Which experiment provided evidence that genetic recombination in bacteria requires direct cell-to-cell contact?

Accepted Answer

Mixing two auxotrophic strains in a U-tube separated by a filter and observing no prototrophs.

Question 5

In E. coli conjugation, what is the role of the F factor?

Accepted Answer

It enables the cell to act as a DNA donor during conjugation.

Question 6

Which of the following best explains why an Hfr x F- mating rarely converts the recipient to F+?

Accepted Answer

The F factor is integrated into the chromosome and transfer is often incomplete before the mating bridge breaks.

Question 7

Which protein is primarily responsible for facilitating single-strand DNA displacement during bacterial recombination?

Accepted Answer

RecA

Question 8

A bacterial cell that has received an F' plasmid containing several chromosomal genes is best described as:

Accepted Answer

A merozygote

Question 9

Which of the following statements about plasmids is FALSE?

Accepted Answer

Plasmids always encode genes for antibiotic resistance.

Question 10

In the classic interrupted mating experiment, why are some genes transferred to the F- cell earlier than others?

Accepted Answer

Genes closer to the origin of transfer on the Hfr chromosome enter the recipient cell first.

Question 11

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

Accepted Answer

Uptake and stable integration of extracellular DNA into a bacterial chromosome.

Question 12

A researcher isolates a bacterial strain that cannot grow on minimal medium unless tryptophan is added. This strain is best classified as:

Accepted Answer

An auxotroph

Question 13

Which of the following is a real-world application of R plasmids in bacteria?

Accepted Answer

They allow bacteria to survive in the presence of antibiotics, leading to the spread of antibiotic resistance in hospitals.

Question 14

If a bacterial cell contains both its own chromosome and a newly acquired F' plasmid with additional genes, what is the genetic state of the cell?

Accepted Answer

Diploid for the genes present on both the chromosome and the F' plasmid

Question 15

Which of the following best explains why selection is a powerful tool in microbial genetics?

Accepted Answer

It enables the growth of only those mutants with a desired trait under specific conditions.

Question 16

Which of the following is NOT a function of bacterial capsules?

Accepted Answer

Replication of the bacterial chromosome

Question 17

A scientist wants to map the order of genes on the E. coli chromosome. Which experimental approach would be most appropriate?

Accepted Answer

Measuring the time at which different genes are transferred during Hfr x F- conjugation (time mapping)

Question 18

Which of the following statements about the RecBCD protein is correct?

Accepted Answer

It is responsible for unwinding double-stranded DNA during recombination.

Question 19

Which of the following is a correct sequence of events during F+ x F- conjugation in E. coli?

Accepted Answer

The F+ cell transfers a copy of the F factor to the F- cell, converting the recipient to F+

Question 20

Which of the following best describes the main function of Col plasmids?

Accepted Answer

They encode colicins that can kill neighboring bacteria.

Genetic Analysis and Mapping in Bacteria (Chapter 6 Study Notes)

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