Question 1

You are looking at a sample from the top green layer of a colorful bacterial mat. Using phase contrast and fluorescence microscopy, you see evenly spaced cells in the middle of a filament that are slightly smaller than the others. The smaller cells are not fluorescent, indicating they lack photosystem II, but the rest of the filament is fluorescent. What type of filamentous bacteria are you most likely looking at?

Accepted Answer

A)   purple nonsulfur bacteria
B)   green sulfur bacteria
C)   Acidobacteria
D)   CyanobacteriaE) A) and B)
F) B) and C)

Question 2

What is convergent evolution and how is it different from horizontal gene transfer?

Accepted Answer

Convergent evolution is the evolution of...

Question 3

Myxobacteria display ________ behavior and form ________ that produce myxospores.

Accepted Answer

A)   gliding / slime trails
B)   chemotactic / colonies
C)   phototactic / slime trails
D)   swarming / fruiting bodiesE) None of the above
F) A) and D)

Question 4

Bacteria that contain complex internal membrane systems are more likely to divide by budding than by binary fission.

Accepted Answer

A) True 
 B)False

Question 5

Most methanotrophs are obligate ________ because ________.

Accepted Answer

A)   aerobes / the initial step of methane oxidation requires O₂
B)   anaerobes / methane is produced in anaerobic environments
C)   fermenters / methane only provides enough energy for fermentation
D)   heterotrophs / methane does not provide enough carbon for growthE) A) and D)
F) A) and C)

Question 6

What growth conditions would you use to enrich for ammonia-oxidizing bacteria?

Accepted Answer

A)   aerobic mineral media with ammonia and bicarbonate incubated in the dark
B)   anaerobic mineral media with acetate and ammonia incubated in the dark
C)   aerobic mineral media with acetate and ammonia incubated in the dark
D)   anaerobic mineral media with ammonia and nitrate incubated in the darkE) C) and D)
F) B) and D)

Question 7

Dissimilatory sulfide-oxidizers use a variety of unique ecological strategies in order to

Accepted Answer

A)   avoid the toxicity of hydrogen sulfide.
B)   position themselves at interfaces where sulfide and oxygen meet.
C)   position themselves where there is sufficient light for sulfide oxidation.
D)   find organic carbon substrates.E) None of the above
F) A) and B)

Question 8

What form of photosynthesis evolved first on Earth?

Accepted Answer

A)   oxygenic
B)   anoxygenic
C)   autotrophic
D)   heterotrophicE) None of the above
F) All of the above

Question 9

All microbial phototrophs

Accepted Answer

A)   fix carbon dioxide.
B)   use water as an electron donor for photosynthesis.
C)   fix carbon dioxide and use water as an electron donor for photosynthesis.
D)   use light energy to drive electron transport to generate energy.E) A) and B)
F) None of the above

Question 10

Discuss the ecological importance of the enzyme nitrogenase, the diversity and physiology of the various groups of organisms that contain it, and the strategies these organisms use to optimize conditions for the enzyme.

Accepted Answer

The enzyme nitrogenase is the only enzym...

Question 11

Green sulfur bacteria are often found at the greatest depths of all phototrophic cells in lakes, oceans, and microbial mats. This is because green sulfur bacteria

Accepted Answer

A)   are very sensitive to UV irradiation, despite their reliance on light for energy.
B)   are the only phototrophs that can use hydrogen sulfide as an electron donor for photosynthesis.
C)   are strict anaerobes.
D)   have chlorosomes that are very efficient at harvesting light, allowing them to perform photosynthesis where light intensities are very low.E) A) and D)
F) A) and B)

Question 12

What is one especially unique characteristic of methanotrophs?

Accepted Answer

A)   They metabolize H2S.
B)   They have unusually large amounts of sterols.
C)   They can exist as consortia.
D)   They are capable of bioluminescence.E) A) and D)
F) None of the above

Question 13

How are anoxygenic phototrophic microorganisms more physiologically diverse than oxygenic phototrophic microorganisms? Be specific in your answers and use examples to illustrate your conclusions.

Accepted Answer

Oxygenic phototrophs (Cyanobacteria) are...

Question 14

The only group of oxygenic phototrophic bacteria are the

Accepted Answer

A)   green nonsulfur bacteria.
B)   Chloroflexi.
C)   Cyanobacteria.
D)   Chlorobi.E) All of the above
F) A) and B)

Question 15

Bioluminescence is controlled by the gene regulatory mechanism called quorum sensing, wherein the

Accepted Answer

A)   depletion of oxygen is detected by an inducer molecule which activates transcription of the lux operon (genes luxCDAB
E)  .
B)   accumulation of an inducer molecule activates transcription of the lux operon (genes luxCDAB
E)  .
C)   absence of light activates an inducer molecule which activates transcription of the lux operon (genes luxCDAB
E)  .
D)   host tissues produce an autoinducer molecule which activates transcription of the lux operon (genes luxCDAB
E)  .E) A) and B)
F) A) and C)

Question 16

How do Cyanobacteria impact the ecology of both aquatic and terrestrial environments on Earth?

Accepted Answer

Cyanobacteria can contribute up to 80% o...

Question 17

Given that multiple diverse phyla (e.g., diverse phylogenetic groups) of microorganisms can perform similar functions in ecosystems, how we might predict the microbial functions performed by a particular organism or in a particular environment without relying on growing all of the microbes in the lab?

Accepted Answer

Without growing all of the microbes in t...

Question 18

Thiobacillus species are acidophilic chemolithotrophs capable of autotrophic growth. They perform the dissimilative oxidation of H₂S, Sᵒ, thiosulfate, or Fe⁺². Diagram or explain how Thiobacillus species obtain carbon and energy for growth and predict what type of environment they would be found in.

Accepted Answer

Thiobacillus species obtain carbon for g...

Question 19

Dissimilative iron-reducing bacteria couple which oxidation-reduction reactions?

Accepted Answer

A)   The reduction of ferric iron or manganese and the oxidation of sulfur.
B)   The reduction of ferric iron or manganese and the fermentation of sugars.
C)   The oxidation of H₂ or organic compounds and the reduction of ferric iron or manganese.
D)   The reduction of ferric iron and photosynthesis.E) A) and C)
F) None of the above

Question 20

Dissimilatory nitrate reduction results in the production of gaseous products, while assimilatory nitrate reduction results in the production of ammonia for biosynthesis.

Accepted Answer

A) True 
 B)False

Exam 15: Functional Diversity of Microorganisms

Discuss the ecological importance of the enzyme nitrogenase, the diversity and physiology of the various groups of organisms that contain it, and the strategies these organisms use to optimize conditions for the enzyme.

Correct Answer
verified
The enzyme nitrogenase is the only enzym...
View Answer

Bacteria that contain complex internal membrane systems are more likely to divide by budding than by binary fission.

Correct Answer
verified

Correct Answer
verified

What is convergent evolution and how is it different from horizontal gene transfer?

Correct Answer
verified
Convergent evolution is the evolution of...
View Answer

Most methanotrophs are obligate because .

Correct Answer
verified

Dissimilatory nitrate reduction results in the production of gaseous products, while assimilatory nitrate reduction results in the production of ammonia for biosynthesis.

Correct Answer
verified

Green sulfur bacteria are often found at the greatest depths of all phototrophic cells in lakes, oceans, and microbial mats. This is because green sulfur bacteria

Correct Answer
verified

What form of photosynthesis evolved first on Earth?

Correct Answer
verified

Correct Answer
verified
Thiobacillus species obtain carbon for g...
View Answer

Dissimilatory sulfide-oxidizers use a variety of unique ecological strategies in order to

Correct Answer
verified

How do Cyanobacteria impact the ecology of both aquatic and terrestrial environments on Earth?

Correct Answer
verified
Cyanobacteria can contribute up to 80% o...
View Answer

How are anoxygenic phototrophic microorganisms more physiologically diverse than oxygenic phototrophic microorganisms? Be specific in your answers and use examples to illustrate your conclusions.

Correct Answer
verified
Oxygenic phototrophs (Cyanobacteria) are...
View Answer

What growth conditions would you use to enrich for ammonia-oxidizing bacteria?

Correct Answer
verified

Myxobacteria display behavior and form that produce myxospores.

Correct Answer
verified

Dissimilative iron-reducing bacteria couple which oxidation-reduction reactions?

Correct Answer
verified

Correct Answer
verified
Without growing all of the microbes in t...
View Answer

What is one especially unique characteristic of methanotrophs?

Correct Answer
verified

All microbial phototrophs

Correct Answer
verified

Bioluminescence is controlled by the gene regulatory mechanism called quorum sensing, wherein the

Correct Answer
verified

The only group of oxygenic phototrophic bacteria are the

Correct Answer
verified

Exam 15: Functional Diversity of Microorganisms

Discuss the ecological importance of the enzyme nitrogenase, the diversity and physiology of the various groups of organisms that contain it, and the strategies these organisms use to optimize conditions for the enzyme.

Correct AnswerverifiedThe enzyme nitrogenase is the only enzym...View AnswerShow Answer

Bacteria that contain complex internal membrane systems are more likely to divide by budding than by binary fission.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

What is convergent evolution and how is it different from horizontal gene transfer?

Correct AnswerverifiedConvergent evolution is the evolution of...View AnswerShow Answer

Most methanotrophs are obligate ________ because ________.

Correct AnswerverifiedShow Answer

Dissimilatory nitrate reduction results in the production of gaseous products, while assimilatory nitrate reduction results in the production of ammonia for biosynthesis.

Correct AnswerverifiedShow Answer

Green sulfur bacteria are often found at the greatest depths of all phototrophic cells in lakes, oceans, and microbial mats. This is because green sulfur bacteria

Correct AnswerverifiedShow Answer

What form of photosynthesis evolved first on Earth?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedThiobacillus species obtain carbon for g...View AnswerShow Answer

Dissimilatory sulfide-oxidizers use a variety of unique ecological strategies in order to

Correct AnswerverifiedShow Answer

How do Cyanobacteria impact the ecology of both aquatic and terrestrial environments on Earth?

Correct AnswerverifiedCyanobacteria can contribute up to 80% o...View AnswerShow Answer

How are anoxygenic phototrophic microorganisms more physiologically diverse than oxygenic phototrophic microorganisms? Be specific in your answers and use examples to illustrate your conclusions.

Correct AnswerverifiedOxygenic phototrophs (Cyanobacteria) are...View AnswerShow Answer

What growth conditions would you use to enrich for ammonia-oxidizing bacteria?

Correct AnswerverifiedShow Answer

Myxobacteria display ________ behavior and form ________ that produce myxospores.

Correct AnswerverifiedShow Answer

Dissimilative iron-reducing bacteria couple which oxidation-reduction reactions?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedWithout growing all of the microbes in t...View AnswerShow Answer

What is one especially unique characteristic of methanotrophs?

Correct AnswerverifiedShow Answer

All microbial phototrophs

Correct AnswerverifiedShow Answer

Bioluminescence is controlled by the gene regulatory mechanism called quorum sensing, wherein the

Correct AnswerverifiedShow Answer

The only group of oxygenic phototrophic bacteria are the

Correct AnswerverifiedShow Answer

Correct Answer
verified
The enzyme nitrogenase is the only enzym...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Convergent evolution is the evolution of...
View Answer

Most methanotrophs are obligate because .

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Thiobacillus species obtain carbon for g...
View Answer

Correct Answer
verified

Correct Answer
verified
Cyanobacteria can contribute up to 80% o...
View Answer

Correct Answer
verified
Oxygenic phototrophs (Cyanobacteria) are...
View Answer

Correct Answer
verified

Myxobacteria display behavior and form that produce myxospores.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Without growing all of the microbes in t...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified