Question 1

Which of the following best describes an auxotrophic mutant in bacteria?

Accepted Answer

A mutant that requires an additional nutrient not needed by the wild-type strain.

Question 2

A frameshift mutation is most likely to occur when:

Accepted Answer

A base pair is deleted or inserted, causing a shift in the reading frame.

Question 3

Which of the following statements about conjugation in bacteria is correct?

Accepted Answer

Conjugation requires direct cell-to-cell contact, often mediated by a pilus.

Question 4

In the context of bacterial genetics, what is the main difference between generalized and specialized transduction?

Accepted Answer

Generalized transduction can transfer any gene, while specialized transduction transfers only specific genes adjacent to prophage integration sites.

Question 5

Which of the following best explains why frameshift mutations generally have more serious consequences than missense mutations?

Accepted Answer

Frameshift mutations alter the reading frame, potentially changing every amino acid downstream of the mutation.

Question 6

A bacterial cell is exposed to UV light, resulting in the formation of thymine dimers. Which DNA repair mechanism is most likely to be activated?

Accepted Answer

SOS repair system

Question 7

Which of the following is a key feature shared by insertion sequences and transposons?

Accepted Answer

Both are mobile genetic elements capable of moving within the genome.

Question 8

A point mutation changes a codon from $$	ext{UAA} ($$stop) to $$	ext{CAA} ($$glutamine). What type of mutation is this?

Accepted Answer

Sense mutation

Question 9

Which of the following best describes the CRISPR system in bacteria?

Accepted Answer

A prokaryotic adaptive immune system that uses stored viral DNA sequences to target and destroy invading phages.

Question 10

During transformation, what is meant by 'competence'?

Accepted Answer

The ability of a cell to uptake and incorporate exogenous DNA from the environment.

Question 11

Which of the following best describes a nonsense mutation?

Accepted Answer

A mutation that changes a codon to a stop codon, resulting in premature termination of translation.

Question 12

A bacterial strain has a genotype change but no observable phenotype change. Which mutation type is most likely responsible?

Accepted Answer

Silent mutation

Question 13

Which of the following best describes rolling circle replication during conjugation?

Accepted Answer

DNA is replicated in both donor and recipient cells simultaneously, allowing both to end up with a complete plasmid copy.

Question 14

Which of the following is NOT a mechanism of horizontal gene transfer in bacteria?

Accepted Answer

SOS repair system

Question 15

A bacterial cell is exposed to ionizing radiation. Which of the following best describes the effect?

Accepted Answer

Breakage of DNA strands, leading to mutations

Question 16

Which of the following is true regarding Hfr conjugation compared to F+ conjugation?

Accepted Answer

Hfr conjugation involves integration of the F plasmid into the chromosome, allowing transfer of chromosomal genes.

Question 17

Which of the following best describes a revertant?

Accepted Answer

A mutant that has reverted to the wild-type phenotype by a second mutation.

Question 18

Which of the following is a common method to screen for auxotrophic mutants?

Accepted Answer

Plating cells on minimal media and identifying colonies that fail to grow.

Question 19

Which of the following best describes a mutagen?

Accepted Answer

A substance that causes mutations by altering DNA structure.

Question 20

A bacteriophage injects its DNA into a bacterial cell, but the DNA is not replicated and instead is packaged into new phage particles. What is this process called?

Accepted Answer

Generalized transduction

Study Guide: Genetics of Bacteria – Key Concepts and Review Questions

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