Question 1

Which of the following best explains why Vibrio vulnificus must 'turn on' different genes when it enters a human host compared to when it lives in seawater?

Accepted Answer

To adapt to the dramatic change in environment and survive immune responses, including producing a protective capsule.

Question 2

What does the term 'turn on' mean in the context of bacterial gene expression?

Accepted Answer

The DNA is read to produce proteins that were previously inactive and not produced in the original environment.

Question 3

Why is Vibrio cholerae unable to infect through the skin, while Vibrio vulnificus can?

Accepted Answer

V. cholerae lacks enzymes to break down skin and tissue, while V. vulnificus is encapsulated and resists phagocytosis.

Question 4

Which of the following is NOT a method by which Enterococcus faecium can acquire antibiotic resistance genes?

Accepted Answer

Binary fission

Question 5

A hospital patient develops a urinary tract infection with multi-drug-resistant Enterococcus faecium. What is the most likely source of the infection?

Accepted Answer

Urinary catheter

Question 6

Which of the following best describes a plasmid?

Accepted Answer

A small, circular DNA molecule found in prokaryotes that can carry antibiotic resistance genes.

Question 7

Which of the following is a real-world example of horizontal gene transfer contributing to a public health crisis?

Accepted Answer

The spread of multi-drug resistance among hospital-acquired Enterococcus faecium infections.

Question 8

Which of the following best defines a genome?

Accepted Answer

All the genes and non-coding DNA in an organism.

Question 9

Which of the following is the correct sequence of events in gene expression?

Accepted Answer

Transcription, then translation

Question 10

Which of the following best describes the function of a codon?

Accepted Answer

A sequence of three mRNA nucleotides that codes for a specific amino acid or signals start/stop of translation.

Question 11

Which of the following is a plausible reason why some bacteria are multi-drug resistant while others are not?

Accepted Answer

Bacteria evolve by acquiring plasmids and resistance genes, especially under antibiotic pressure.

Question 12

Which of the following best describes the role of tRNA during translation?

Accepted Answer

It brings specific amino acids to the ribosome by matching its anticodon to the mRNA codon.

Question 13

Which of the following is a key difference between genotype and phenotype?

Accepted Answer

Genotype refers to the genetic makeup, while phenotype refers to observable traits.

Question 14

Which of the following is true about Okazaki fragments?

Accepted Answer

They are short DNA fragments synthesized on the lagging strand during DNA replication.

Question 15

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

Accepted Answer

Uptake of naked DNA from the environment by a bacterial cell.

Question 16

Which of the following is a practical way hospital personnel can prevent the spread of multi-drug-resistant bacteria?

Accepted Answer

Strict handwashing and infection control protocols.

Question 17

Which of the following is the correct base pairing in DNA?

Accepted Answer

$$A$$ pairs with $$T$$, $$C$$ pairs with $$G$$

Question 18

Which of the following is a function of a bacterial capsule in pathogenesis?

Accepted Answer

It helps bacteria resist phagocytosis by host immune cells.

Question 19

Which of the following best describes the role of RNA polymerase in transcription?

Accepted Answer

It synthesizes RNA from a DNA template.

Question 20

A patient is infected with a bacterium that can survive in both salt water and human tissue. Which genetic mechanism most likely allows this adaptation?

Accepted Answer

Regulation of gene expression in response to environmental signals.

Chpt 7 Study Guide

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