Question 1

Which of the following phyla contains the majority of known medically, industrially, and agriculturally significant bacteria?

Accepted Answer

Proteobacteria

Question 2

What is the primary molecular marker used to distinguish major bacterial phyla in phylogenetic studies?

Accepted Answer

16S ribosomal RNA

Question 3

A newly discovered bacterium is gram-negative, metabolically versatile, and found in soil. It is most likely a member of which class?

Accepted Answer

Gammaproteobacteria

Question 4

Which class of Proteobacteria is known for containing obligate intracellular parasites such as Rickettsia and Wolbachia?

Accepted Answer

Alphaproteobacteria

Question 5

Which genus is most likely to be found as a probiotic in fermented dairy products and is resistant to acidic conditions?

Accepted Answer

Lactobacillus

Question 6

A patient presents with symptoms of typhoid fever. Which genus is most likely responsible for this disease?

Accepted Answer

Salmonella

Question 7

Which metabolic pathway is characteristic of Escherichia, Salmonella, and Shigella during glucose fermentation?

Accepted Answer

Mixed-acid fermentation

Question 8

Which genus is known for producing antibiotics and is responsible for the characteristic earthy odor of soil?

Accepted Answer

Streptomyces

Question 9

Which of the following bacteria lack a cell wall and are resistant to osmotic lysis due to sterols in their membrane?

Accepted Answer

Mycoplasma

Question 10

A gram-positive, catalase-positive, rod-shaped bacterium that grows well at low temperatures and is associated with foodborne illness is most likely:

Accepted Answer

Listeria

Question 11

Which genus is responsible for forming root nodules and fixing nitrogen in symbiotic association with legumes?

Accepted Answer

Rhizobium

Question 12

Which genus is a strict respiratory chemoorganotroph, can fix nitrogen, and is an opportunistic pathogen in humans?

Accepted Answer

Burkholderia

Question 13

Which genus of bacteria is rod-shaped, facultative aerobe, and produces the antioxidant pigment violacein?

Accepted Answer

Chromobacterium

Question 14

Which genus is known for swarming motility and is a frequent cause of urinary tract infections in humans?

Accepted Answer

Proteus

Question 15

Which genus forms red pyrrole-containing pigments called prodigiosins and may cause infection in humans?

Accepted Answer

Serratia

Question 16

Which genus is a facultative aerobe, grows in clusters, is catalase-positive, and is resistant to drying and high salt?

Accepted Answer

Staphylococcus

Question 17

Which genus is responsible for producing toxic insecticidal proteins and is used as a biological control agent?

Accepted Answer

Bacillus

Question 18

Which genus is an obligate intracellular parasite of eukaryotes, has a unique developmental cycle, and is susceptible to beta-lactam antibiotics?

Accepted Answer

Chlamydia

Question 19

Which bacterium is extremely resistant to radiation due to efficient DNA repair systems and unique DNA arrangement?

Accepted Answer

Deinococcus radiodurans

Question 20

Which genus is commonly found in dental plaque, is an obligate anaerobe, and is implicated in oral and systemic diseases?

Accepted Answer

Fusobacterium

Phylogenetic Diversity of Bacteria: Major Bacterial Phyla and the Proteobacteria

Study Guide - Practice Questions