Question 1

Which of the following statements best explains why Pelagibacter is one of the most abundant microorganisms in the ocean?

Accepted Answer

It is extremely small and can grow with very low levels of nutrients, giving it a competitive advantage in nutrient-poor environments.

Question 2

A patient presents with a high fever and a spotted rash after a recent hiking trip. Laboratory tests reveal an obligate intracellular, Gram-negative bacterium. Which organism is most likely responsible for the infection?

Accepted Answer

Rickettsia rickettsii

Question 3

Which of the following bacteria is known for causing foodborne illness and has over 2500 serovars, making serological identification important?

Accepted Answer

Salmonella

Question 4

A scientist is studying bacteria that can convert ethanol into acetic acid. Which genus is most likely being investigated?

Accepted Answer

Acetobacter

Question 5

Which of the following best describes the role of cyanobacteria in Earth's history?

Accepted Answer

They significantly increased the atmospheric $$O_2$$ content through oxygenic photosynthesis.

Question 6

A hospital patient develops a wound infection with a bacterium that is Gram-negative, has polar flagella, and is metabolically diverse. Which organism is most likely responsible?

Accepted Answer

Pseudomonas aeruginosa

Question 7

Which of the following bacteria is transmitted by fleas and is responsible for causing plague?

Accepted Answer

Yersinia pestis

Question 8

A 5-year-old child presents with a severe cough and is diagnosed with whooping cough. Which bacterium is the causative agent, and what is a key characteristic of this genus?

Accepted Answer

Bordetella pertussis; nonmotile rods

Question 9

Which of the following statements about Mycobacterium is correct?

Accepted Answer

It has a cell wall with a thick peptidoglycan layer covered by mycolic acids, making it waxy and water-resistant.

Question 10

A patient is diagnosed with Q fever after exposure to contaminated milk. Which bacterium is responsible, and what is its primary mode of transmission?

Accepted Answer

Coxiella burnetii; transmitted via aerosols or contaminated milk

Question 11

Which of the following best explains why Mycoplasma pneumoniae is resistant to antibiotics that target cell wall synthesis?

Accepted Answer

It lacks a cell wall and instead has sterols in its membrane.

Question 12

A microbiologist isolates a bacterium from soil that forms branching filaments and produces antibiotics. Which genus is most likely being studied?

Accepted Answer

Streptomyces

Question 13

Which of the following bacteria is a common cause of nosocomial infections and produces a distinctive red pigment?

Accepted Answer

Serratia marcescens

Question 14

A patient with a history of eating undercooked chicken develops severe diarrhea. Which bacterium is most likely responsible, and what is a key feature of its physiology?

Accepted Answer

Campylobacter jejuni; microaerophilic with a single polar flagellum

Question 15

Which of the following is a distinguishing feature of Chlamydia trachomatis compared to most other bacteria?

Accepted Answer

It lacks peptidoglycan in its cell wall and forms an elementary body that is infective.

Question 16

Which of the following best describes the metabolic strategy of enteric bacteria such as Escherichia coli?

Accepted Answer

They are facultative anaerobes that ferment carbohydrates.

Question 17

A laboratory technician is working with a bacterium that is an obligate anaerobe, forms endospores, and is known to cause tetanus. Which genus does this bacterium belong to?

Accepted Answer

Clostridium

Question 18

Which of the following Archaea would be most likely to thrive in a salt lake with a salt concentration of 30%?

Accepted Answer

Halophiles

Question 19

A patient develops pneumonia after a viral infection. The causative agent is a Gram-positive, alpha-hemolytic coccus. Which organism is most likely responsible?

Accepted Answer

Streptococcus pneumoniae

Question 20

Which of the following best explains why Wolbachia is being considered for use in mosquito control programs?

Accepted Answer

It affects the reproduction of insects, potentially reducing the spread of mosquito-borne diseases.

Chapter 11

Study Guide - Practice Questions

Study Guide - Flashcards