Question 1

Which of the following best describes the difference between vertical and horizontal gene transfer in bacteria?

Accepted Answer

Vertical gene transfer is the transmission of genetic material from parent to offspring, while horizontal gene transfer involves the acquisition of genetic material from another organism that is not its parent.

Question 2

During DNA replication in bacteria, which enzyme is responsible for synthesizing the majority of the new DNA strand?

Accepted Answer

DNA polymerase III

Question 3

A mutation changes the codon UAU to UAA in a bacterial gene. What is the most likely effect of this mutation?

Accepted Answer

It will introduce a stop codon, leading to premature termination of translation.

Question 4

Which of the following best explains the role of sigma factors in bacterial transcription?

Accepted Answer

Sigma factors help RNA polymerase recognize promoter regions and initiate transcription.

Question 5

Which of the following antibiotics inhibits bacterial transcription by binding to RNA polymerase?

Accepted Answer

Rifampin

Question 6

A bacterial cell is exposed to a chemical that prevents the formation of Okazaki fragments. Which process will be most directly affected?

Accepted Answer

Synthesis of the lagging strand during DNA replication

Question 7

Which of the following best describes the function of the lac operon in E. coli?

Accepted Answer

It controls the expression of genes involved in lactose metabolism, allowing the cell to use lactose as an energy source when glucose is absent.

Question 8

Which of the following is a consequence of a mutation in the gene encoding DNA gyrase in bacteria?

Accepted Answer

The cell may be unable to relieve supercoiling during DNA replication, leading to replication stress.

Question 9

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

Accepted Answer

Transfer of DNA from one bacterium to another via a pilus, typically involving an F plasmid.

Question 10

A bacterial cell is growing in a medium containing both glucose and lactose. Which of the following best describes the regulation of the lac operon under these conditions?

Accepted Answer

The lac operon is repressed because glucose is present, even though lactose is available.

Question 11

Which of the following statements about the leading and lagging strands during DNA replication is correct?

Accepted Answer

The leading strand is synthesized continuously, while the lagging strand is synthesized discontinuously as Okazaki fragments.

Question 12

Which of the following best explains the effect of a nonsense mutation in a coding region of a bacterial gene?

Accepted Answer

It introduces a premature stop codon, truncating the protein.

Question 13

Which of the following is the correct sequence of events in bacterial transcription initiation?

Accepted Answer

Binding of RNA polymerase and sigma factor to the promoter, followed by unwinding of DNA and initiation of RNA synthesis.

Question 14

Which of the following best describes the role of the core polymerase in bacterial transcription?

Accepted Answer

It synthesizes RNA from the DNA template after sigma factor dissociates.

Question 15

A bacterial cell is treated with an antibiotic that blocks the A site of the ribosome. What is the most direct effect of this treatment?

Accepted Answer

Inhibition of tRNA binding during translation, preventing protein synthesis

Question 16

Which of the following is a function of the enzyme primase during DNA replication?

Accepted Answer

Synthesizing short RNA primers to provide a starting point for DNA polymerase

Question 17

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

Question 18

Which of the following is the correct formula for calculating the melting temperature ($$T_m) of a $$DNA duplex, given the number of $$G$$-$$C$$ and $$A$$-$$T$$ base pairs?

Accepted Answer

$$T_m = 2 	imes (	ext{number of } A	ext{-}T) + 4 	imes (	ext{number of } G	ext{-}C)$$

Question 19

Which of the following best explains the effect of glucose on the lac operon in E. coli?

Accepted Answer

Glucose represses the lac operon by decreasing cAMP levels, reducing CAP binding and transcription.

Study Guide: Microbial Genetics, Gene Expression, and Regulation (Chapters 7-10)

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