Topic 7 - Bacterial MVPs - Clickers Flashcards
Nutrient agar plates would be a good place to start for the culture of which bacteria?
a)Nitrosomonas
b)Pseudomonas
c)Methanococcus
d)Rhodomicrobium
e)Cyanobacteria
b) Pseudomonas
Explanation: Nutrient agar plates are suitable for cultivating Pseudomonas species due to their non-fastidious nature, meaning they do not require specific growth factors or conditions.
Which of the following statements is/are FALSE?
a) Nitrifiers and methanotrophs use internal membranes for energy generation
b) Both purple sulfur and purple nonsulfur bacteria can use reduced sulfur (i.e., hydrogen sulfide; H2S) for electrons
c) All subdivisions of Proteobacteria have photosynthetic species
d) Penicillin is a broad-spectrum antibiotic
e) Bacteriostatic or bacteriocidal? Sometimes depends on concentration
c) All subdivisions of Proteobacteria have photosynthetic species E
Explanation: Not all Proteobacteria subdivisions are photosynthetic. While some have photosynthetic species, others, like Enterobacteria, are heterotrophic.
Order these bacteria from top to bottom: (1-5, respectively) in a Winogradsky column.
Cyanobacteria
Fermenters and sulfate reducers
Purple nonsulfur bacteria
Green sulfur bacteria
Purple sulfur bacteria
1) Cyanobacteria
2) Purple nonsulfur bacteria
3) Purple sulfur bacteria
4) Green sulfur bacteria
5) Fermenters and sulfate reducers
Explanation: The order reflects their positioning based on light and oxygen gradients in the column.
Ammonia monooxygenase, methane monooxygenase, and carotenoids are all involved in what key microbial activity?
a)Anaerobic metabolism
b)Harvesting light
c)Organic carbon oxidation
d)Energy conservation
e)Motility
d) Energy conservation
Explanation: These enzymes and molecules are crucial for metabolic processes that conserve energy, such as ammonia oxidation and methane oxidation.
Match the bacterium to the flagellar arrangement.
____Peritrichous
____Polar
- Escherichia coli
- Pseudomonas aeruginosa
1) Peritrichous: Escherichia coli
Explanation: Escherichia coli exhibits peritrichous flagella
2) Polar: Pseudomonas aeruginosa
Explanation: Pseudomonas aeruginosa has polar flagella, facilitating different types of motility
Which statement is TRUE?
a) Escherichia coli has a single polar flagellum
b) Bdellovibrio is a chemoorganoheterotroph
c) Myxococcus and Dictyostelium both have diploid life-cycle stages
d) Agrobacterium and rhizobium are both parasitic
e) All coliforms are gut-associated
b) Bdellovibrio is a chemoorganoheterotroph
Explanation: Bdellovibrio is a chemoorganoheterotroph because it obtains energy by consuming organic compounds derived from other organisms.
Why do you think myxobacteria produce pigmented fruiting bodies for distribution of their desiccation-resistant spores?
a) Antioxidants
b) Photosynthesis
c) Aesthetics
a) Antioxidants
Explanation: The pigments in myxobacteria fruiting bodies act as antioxidants, protecting the spores from oxidative damage.
Which of the following is NOT a characteristic of Myxobacteria?
a) Gliding motility
b) Lyse other cells for nutrients
c) Relatively small chromosome
d) Nutrient limitation leads to differentiation
e) Desiccation resistant spores
c) Relatively small chromosome
Explanation: Myxobacteria have relatively large and complex genomes to support their social behaviors and differentiation processes.
Which is the correct order of events?
a) Flavonoids, nod factors, root curling, infection thread
b) Root curling, flavonoids, infection thread, nod factors
c) Root curling, nod factors, flavonoids, infection thread
d) Flavonoids, root curling, nod factors, infection thread
e) Nod factors, root curling, infection thread, flavonoids
a) Flavonoids, nod factors, root curling, infection thread
Explanation: Flavonoids released by plants induce nod factor production by bacteria, which triggers root curling and formation of the infection thread.
A homofermenter produces:
a) all of these options
b) lactic acid
c) ethanol
d) CO2
b) lactic acid
Explanation: Homofermenters produce lactic acid as the primary end product of fermentation, without generating other byproducts like ethanol or CO2 in significant quantities.
Which of the following experimental procedures could be used to distinguish between Micrococcus and Streptococcus isolates? (choose any that apply)
a) Expose to high salt concentrations (~7.5%) and see if it survives
b) Test whether anaerobic growth is possible
c) Observe carefully with a microscope and see if it grows as cocci
d) Treat with a high dose of antibiotics and see if it survives
a) Expose to high salt concentrations (~7.5%) and see if it survives
b) Test whether anaerobic growth is possible
Explanation: Micrococcus and Streptococcus can be distinguished based on their ability to tolerate high salt concentrations (Micrococcus is salt-tolerant, Streptococcus is not) and growth under anaerobic conditions (Streptococcus can grow anaerobically, Micrococcus cannot).
Which of the following is FALSE concerning nitrogen fixation?
a) Leghemoglobin is involved in protecting nitrogenase from inactivation
b) The bacteria that do this within legumes form crown gall tumours
c) Nitrogenase is inactivated by O2
d) Lots of ATP required – it is an expensive process
b) The bacteria that do this within legumes form crown gall tumours
Explanation: The bacteria that perform nitrogen fixation within legumes form nodules, not crown gall tumours, which are associated with pathogenic interactions involving Agrobacterium species. This makes option b false.
Leghemoglobin binds oxygen to protect nitrogenase, which is sensitive to oxygen.
Lactic acid bacteria
a) Staphylococcus
b) Bacillus
c) Streptococcus
d) Clostridium
e) Micrococcus
c) Streptococcus
Explanation: Streptococcus is a genus of lactic acid bacteria known for fermenting sugars into lactic acid.
Who might produce geosmins?
a) Methanotrophs
b) Pseudomonas
c) Nitrosomonas
d) Chromatium
e) Streptomyces
e) Streptomyces
Explanation: Streptomyces, a genus of actinobacteria, produces geosmin, which gives soil its characteristic earthy smell.
Who does NOT have intracytoplasmic membranes?
a) Cyanobacteria
b) Nitrosomonas
c) Methanotrophs
d) Pseudomonas
e) Chromatium
d) Pseudomonas
Explanation: Pseudomonas is a genus of bacteria that does not have specialized intracytoplasmic membranes for photosynthesis or nitrification.
What do Cyanobacteria store in their thylakoid membranes? (Choose all that apply)
a) phycobilins
b) chlorophyll
c) crystal protoxins
d) nitrogenase
e) bacteriochlorophyll
a) phycobilins, b) chlorophyll
Explanation: Cyanobacteria store phycobilins and chlorophyll in their thylakoid membranes, which are essential for capturing light during photosynthesis.
Bdellovibrio creates a “spheroplast” or “bdelloplast” of its prey, which would be similar in effect to treating the cell with… (choose any that apply)
a) Lysozyme
b) Polymyxin B
c) Tetracycline
d) Penicillin
e) Ethanol
a) Lysozyme and d) Penicillin
Explanation: Lysozyme breaks down the bacterial cell wall by cleaving glycosidic bonds in peptidoglycan, while penicillin inhibits the cross-linking of peptidoglycan, both leading to cell wall weakening and spheroplast formation.
