Deck 18: Bacterial Diversity

Question 1

Dehalobacter restrictus conducts anaerobic respiration by

A) reducing aromatic rings of lignin-derived compounds.
B) donating electrons to Fe3+, converting it to Fe2+ in mine ores.
C) donating electrons to Cl atoms, effectively performing dechlorination.
D) donating electrons to NO3-, yielding NO₂-.
E) donating electrons to SO₄^2-, yielding HS-.

Answer 1

C

Question 2

Which of the following is an extremophile?

A) Bacillus alkalophilus
B) Bacillus thuringiensis
C) Bacillus subtilis
D) Clostridium botulinum
E) Clostridium tetani

Answer 2

A

Question 3

Which of the following factors is NOT involved in initiation of spore formation in firmicutes?

A) carbon starvation
B) light limitation
C) phosphate starvation
D) nitrogen starvation
E) low pH

Answer 3

B

Question 4

Which of the following is NOT correct about microorganisms in the phylum Thermotogae?

A) They are bacterial thermophiles.
B) Archaeal genes have been transferred horizontally to them.
C) They have mosaic genomes.
D) They are bacteria with sheath-like outer structures.
E) They are aerobic heterotrophs.

Question 5

The following figure represents the life cycle of which bacteria?

A) clostridiales
B) verrucomicrobia
C) Streptomyces
D) myxobacteria
E) cyanobacteria

Question 6

Cyanobacteria are the only prokaryotes that use ________ to photolyze water to produce oxygen.

A) photosystem I alone
B) bacteriochlorophyll
C) both photosystems I and II
D) plastocyanin
E) carboxyzomes

Question 7

Bacteria are widely diverse in their cell structure, metabolism, and ecological adaptations, but share some major common traits. Which of the following statements is NOT true?

A) They share common features in central apparatus for gene expression and translation.
B) Bacterial gene expression mechanisms differ from those of the eukaryotes, which underlies the selective activity of many antibiotics.
C) Some archaeal cell walls are composed of pseudopeptidoglycan and may have fundamentally different antibiotic sensitivity than bacteria.
D) Mycoplasmas contain abnormal peptidoglycans and are thus not susceptible to antibiotics.
E) In bacteria, variant forms of peptidoglycan distinguish different species.

Question 8

Cyanobacteria contain subcellular structures called carboxysomes that are rich in the enzyme ________ that fixes CO₂.

A) decarboxylase
B) oxidase
C) urease
D) cellulase
E) Rubisco

Question 9

The firmicutes ________ are the only known phototrophs that produce endospores.

A) actinomycetales
B) bacillales
C) clostridiales
D) heliobacteriaceae
E) cyanobacteria

Question 10

Which of the following species of Bacillus produces a biological insecticide?

A) B. subtilis
B) B. anthracis
C) B. thuringiensis
D) B. thermophilus
E) B. halodurans

Question 11

An ancient ________ is assumed to be in the same lineage as mitochondria.

A) Rhizobium
B) Mycoplasma
C) Clostridium
D) Rickettsia
E) cyanobacterium

Question 12

All of the following are mechanisms that provide an anoxic environment for nitrogen fixation in cyanobacteria EXCEPT

A) formation of heterocysts.
B) formation of chlorosomes.
C) temporal separation of photosynthesis and nitrogen fixation.
D) accumulation of large aggregates of cells.
E) symbiotic associations with fungi or plants.

Question 13

Which of the following is NOT correct about the non-spore-forming firmicutes?

A) This group includes lactic acid bacteria such as Lactococcus and Lactobacillus.
B) They include the mycoplasmas, which possess cell walls made of pseudopeptidoglycan.
C) Food spoilers such as Leuconostoc and Pediococcus belong to this group.
D) They may have evolved from endospore-forming bacteria.
E) Listeria species include enteric pathogens that contaminate cheese and sauerkraut.

Question 14

Clades of microbes that are recently defined or characterized are referred to as

A) hyperthermophiles.
B) archaea.
C) phyla.
D) deep branching.
E) emerging.

Question 15

A trait that differentiates all Firmicutes from Actinobacteria is

A) Gram stain character.
B) GC content.
C) oxygen requirements.
D) pathogenicity.
E) genome size.

Question 16

Bacteria in the genera ________ produce durable endospores that remain viable for millennia.

A) Carboxydothermus and Listeri
B) Lactobacillus and Streptococcus
C) Bacillus and Clostridium
D) Oscillatoria and Anabaena
E) Rickettsia and Chromatium

Question 17

A bacterial phylum is a group of organisms that share a common ancestor that diverged early from other bacteria, based on

A) small-subunit (16S) rRNA sequences.
B) the presence of certain plasmids.
C) their genomic size.
D) having 70S or 80S ribosomes.
E) the presence or absence of a cell wall.

Question 18

Cyanobacteria participate in multilayered microbial mats with sulfur phototrophs. These other phototrophs absorb light if they lie below the cyanobacteria by

A) growing anaerobically.
B) producing phycocyanin.
C) absorbing light at shorter wavelengths than cyanobacteria.
D) absorbing light at longer wavelengths than cyanobacteria.
E) absorbing UV irradiation.

Question 19

Which of the following is NOT a common cyanobacterial morphology?

A) single-celled
B) endospore
C) colonial
D) filamentous
E) akinete

Question 20

In what environment does Savagella form filaments through the production of intracellular offspring?

A) aquatic, high salinity environments
B) hydrothermal springs
C) surgical wounds
D) mammalian skin tissue
E) mammalian gut epithelium

Question 21

Pseudomonas aeruginosa may form ________ in the lungs of cystic fibrosis patients.

A) sarcinae
B) filaments
C) biofilms
D) cysts
E) capsules

Question 22

Which phylum contains the purple bacteria?

A) cyanobacteria
B) proteobacteria
C) actinobacteria
D) fusobacteria
E) firmicutes

Question 23

Which of the following is NOT correct about the outer membrane of Gram-negative proteobacterial cell wall?

A) It has receptor proteins and porins.
B) In pathogens, lipopolysaccharide facilitates phagocytosis.
C) Lipopolysaccharide is toxic when released by dying cells.
D) It is a lipid bilayer membrane.
E) Lipopolysaccharide is absent in the cytoplasmic membrane.

Question 24

Dehalobacter restrictus could be used in bioremediation because it

A) respires by donating electrons to Cl atoms in tetrachloroethene, used in dry cleaning.
B) is an anaerobe that quickly digests plastics in landfills.
C) catabolizes aromatic compounds by reductive degradation.
D) removes salt from salt marshes.
E) is not applicable for use in bioremediation.

Question 25

Which phylum of deep-branching Gram-negative bacteria are often found in dental plaques?

A) Aquificae
B) Proteobacteria
C) Acidobacteria
D) Fusobacteria
E) Chlorobi

Question 26

Which of the following is NOT correct with respect to the mycoplasmas?

A) They have lost their cell wall and the S-layer through reductive evolution.
B) Their cells maintain their shape through a type of cytoskeleton.
C) When cultured on agar, their colonies have a "fried-egg" shape.
D) They are parasites of all kinds of multicellular organisms.
E) They have some of the largest bacterial genomes.

Question 27

Photoheterotrophs absorb light for energy, but do NOT typically

A) produce endospores.
B) generate biomass from carbohydrates.
C) fix nitrogen.
D) fix carbon dioxide.
E) grow oligotrophically.

Question 28

Where do Chromatium cells store sulfur?

A) in cytoplasmic granules
B) in periplasmic granules
C) in attached sulfur globules
D) in their immediate environment
E) in cytoplasmic vacuoles

Question 29

Which feature, indicated in the following figure, do Chlorobi share with Chloroflexi and Chloracidobacterium thermophilum?

A) chlorosomes
B) thylakoids
C) halophily
D) endospores
E) hormogonia

Question 30

Which of the following is NOT correct about the sulfur lithotrophic genus Beggiatoa?

A) It is a Gram-negative gammaproteobacterial genus.
B) It oxidizes H₂S to S0.
C) It stores S0 in cytoplasmic granules.
D) It stores polyhydroxybutyrate.
E) It grows as extended filaments.

Question 31

Which of the following is NOT correct about myxobacteria?

A) Myxobacterial fruiting bodies are similar to those of the eukaryotic slime molds.
B) Under nutrient scarcity, their cells attract each other and form fruiting bodies.
C) They are aquatic and live as commensals on fish scales.
D) They lack flagella and move along surfaces using a form of motility called gliding.
E) With up to 12.6 Mbp, their genomes are exceptionally large.

Question 32

Corynebacterium species have a particular type of cell division that can be described as

A) "half-snapping."
B) the formation of reticulate bodies.
C) the formation of a forespore and a mother cell.
D) stalking.
E) "live birth."

Question 33

The type of telomere pictured below is found in

A) rickettsias and mitochondria.
B) cyanobacteria and chloroplasts.
C) Streptomyces.
D) Planctomycetes.
E) Deinococcus-Thermus.

Question 34

Which of the following is NOT correct with respect to the species of Frankia?

A) It belongs to the phylum Actinobacteria.
B) It can live as an endophyte in the roots of some vascular plants, where it fixes nitrogen.
C) Some species can protect plants, such as wheat, from fungal infection.
D) Some species can grow as saprophytes on dead leaf litter.
E) Some species have been found to form spores.

Question 35

The following bacterial genera belong to the Enterobacteriaceae. In particular, the heavily flagellated ________ display swarming behavior prior to forming ________.

A) Escherichia; colonies
B) Proteus; biofilms
C) Pseudomonas; endospores
D) Caulbacter; stalks
E) Myxobacteria; fruiting bodies

Question 36

Which of the following is NOT correct regarding rhizobia?

A) Rhizobium, Bradyrhizobium, and Synorhizobium are among the genera comprising rhizobia.
B) They may live freely in soil, but they prefer to establish symbioses with specific legumes.
C) They form nodules in the roots to favor anaerobiosis and consequently nitrogen fixation.
D) They provide the host with leghemoglobins, which help the plant hosts combat pathogens.
E) Each species colonizes a particular host range for infection.

Question 37

In sewage-treatment systems, nitrifiers such as ________ are used to decrease the reduced nitrogen content.

A) Neisseria gonorrhoeae and N. meningitidis
B) Thiobacillus spp.
C) Nitrosomonas, Nitrosolobus, and Nitrosovibrio
D) Escherichia spp.
E) Helicobacter and Campylobacter

Question 38

Which gammaproteobacteria genera include species that oxidize H₂S to S⁰?

A) Escherichia and Enterobacter
B) Chromatium and Beggiatoa
C) Klebsiella and Shigella
D) Proteus and Erwinia
E) Rhodobacter and Nitrosomonas

Question 39

Which of the following is pathogenic?

A) Mycobacterium smegmatis
B) Blastochloris viridis
C) Leptospirillum spp.
D) Acidithibacillus ferrooxidans
E) Neisseria gonorrhoeae

Question 40

Bacteroidetes are important components of what ecosystem?

A) Antarctic brine lakes
B) the termite gut
C) hydrothermal springs
D) the human gut
E) acid mines

Question 41

Chlamydiae, Planctomycetes, and Verrucomicrobia share which of the following traits?

A) oligotrophy
B) intracellular compartmentalization
C) phototrophy
D) diminished or no cell walls
E) endospore formation

Question 42

Which is NOT a typical characteristic of Verrucomicrobia?

A) They contain a cytoskeleton made from tubulin.
B) They are oligotrophic.
C) They are rarely cultured.
D) They appear to have acquired genes through horizontal transfer from eukaryotes.
E) They are obligate intracellular parasites.

Question 43

In order to learn what makes proteins stable in thermophilic bacteria, how should the amino acids or motifs that are involved in conferring thermostability to proteins be explored?

Question 44

Describe the photosynthetic machinery of cyanobacteria.

Question 45

Which of the following statements is NOT correct regarding the life cycle of Chlamydia?

A) Elementary bodies are taken up by the host cells via endocytosis.
B) Reticulate bodies differentiate from elementary bodies outside the host cell.
C) A reticulate body may persist in the host cell for long periods.
D) Reticulate bodies replicate and develop into elementary bodies.
E) Elementary bodies are metabolically inert with a compacted chromosome, resembling spores.

Question 46

What distinguishes bacterial cell walls from those in archaea and eukarya?

Question 47

Bacteria in the genus Nitrospira

A) are Gram-negative, true lithotrophs or autotrophs.
B) possess carboxysomes, where they fix carbon dioxide or carbonate.
C) remove excess nitrite in aquatic ecosystems.
D) form symbiotic associations with other bacteria.
E) are generally found in freshwater or salt water.

Question 48

What bacterial groups use actin as a means to leave their host cells? What advantage does this type of cellular invasion provide to intracellular pathogens?

Question 49

Treponema azotonutricium is known for its symbiotic association with

A) phototrophs in microbial mats.
B) corals.
C) fungi in lichens.
D) protists in the termite gut.
E) the mammal epithelium.

Question 50

Which genus within the spirochetes includes the causative agent of Lyme disease?

A) Treponema
B) Holandina
C) Leptospira
D) Borrelia
E) Spirochaeta

Question 51

Discuss the chemical nature of mycolic acids and some of the traits they confer to organisms that possess them.

Question 52

Which of the following is NOT a common feature in many spirochetes?

A) tight spiral morphology
B) heterotrophy
C) thick outer sheaths
D) periplasmic flagella
E) rigid cell walls

Question 53

The ________ lack cell walls and have a double membrane around the nucleoid; their tolerance for low concentrations of nutrients is called ________.

A) Verrucomicrobia; ectosymbiosis
B) Planctomycetes; oligotrophy
C) Chlamydiae; endosymbiosis
D) Cyanobacteria; oligotrophy
E) Firmicutes; piezophily

Question 54

Methylobacterium species are methylotrophs, which means that they

A) can oxidize reduced single-carbon compounds.
B) exclusively feed on methane.
C) generate methane as a product of fermentation.
D) perform bacteriochlorophyll-based photosynthesis.
E) are classified as lithotrophs.

Question 55

Describe three mechanisms cyanobacteria use to provide an anoxic environment for the oxygen-sensitive, nitrogen-fixation enzyme nitrogenase.

Question 56

What is photoheterotrophy? Provide two examples.

Question 57

Describe the lifestyle and development of Streptomyces mycelia.

Question 58

Why is it that the deep-branching thermophiles may appear to have diverged from other bacteria earlier than they actually did?

Question 59

Which of the following have multipartite genomes?

A) Borrelia spp.
B) Escherichia spp.
C) Bacillus spp.
D) Chlamydia spp.
E) Mycobacterium spp.

Question 60

Some Gram-negative bacteria branch more deeply from the proteobacteria than the five Greek-lettered classes do from each other. Which phyla listed below is deep-branching Gram-negative?

A) Thermotogo
B) Aquifex
C) Flavobacteria
D) Protobacteria
E) Chlorobi

Question 61

After reading the news of an E. coli threat in the community, your family and friends ask you, "Is E. coli a pathogen?" What would you answer?

Question 62

What is unique about the genome of Borrelia species?

Question 63

The epsilonproteobacterium Helicobacter pylori is the cause of gastritis and stomach ulcers. What mechanism allows it to survive the acidic conditions of the mammalian stomach?

Question 64

Describe the metabolic characteristics of Chlorobium species.

Question 65

Outline the process illustrated in the following figure.

Question 66

Describe the cell wall of Verrucomicrobia. How could these organisms have acquired this trait?

Question 67

How could nitrifiers be utilized in treatment of wastewater?

Question 68

How do Bacteroides fragilis and B. thetaiotaomicron contribute to 15% of human caloric intake? Are there other benefits provided by these microbes to human health? Are they potentially pathogenic?

Question 69

Compare and contrast the double membrane found in Planctomycetes versus that found in the eukaryotic nucleus.

Question 70

What are oligotrophs? Provide two examples of oligotrophic bacteria.

Question 71

Describe the unique way in which spirochetes can be isolated from other environmental species. What makes this possible?