Question 1

Which of the following conditions would you use to enrich purple nonsulfur bacteria from lake sediments?

Accepted Answer

A)  anoxic media with a good light source 
B)  mineral media with ammonia and oxygen in the dark 
C)  anoxic mineral media with an organic acid and a good light source 
D)  mineral media with nitrate and acetate in the dark 
A)  anoxic media with a good light source 
B)  mineral media with ammonia and oxygen in the dark 
C)  anoxic mineral media with an organic acid and a good light source 
D)  mineral media with nitrate and acetate in the dark

Question 2

Which group of bacteria would you expect to find in a shallow clear hot spring with high concentrations of geochemically produced hydrogen sulfide?

Accepted Answer

A)  purple sulfur bacteria 
B)  single-celled Cyanobacteria 
C)  dissimulative sulfate-reducing bacteria 
D)  symbiotic diazotrophs 
A)  purple sulfur bacteria 
B)  single-celled Cyanobacteria 
C)  dissimulative sulfate-reducing bacteria 
D)  symbiotic diazotrophs

Question 3

Tilling or plowing is a common agriculture practice that has been proven to have a profound impact on the nitrogen cycle. Tilling breaks up hard soils to ease the planting and germination of crops, and it also introduces more oxygen into the soil. Many fertilizers contain N in the form of ammonia because ammonia is readily absorbed and used by plants, while N in the form of nitrate is more mobile and is more easily lost from the soil. Based on your knowledge of microbial transformations of inorganic nitrogen species, what impact would you predict extensive tilling to have on the fate of ammonium-based nitrogen fertilizer?

Accepted Answer

Ammonia-oxidizing and nitrite-oxidizing

Question 4

Aside from using light as a source of energy, another important part of the functional diversity of some bacterial phototrophs is their ability to

Accepted Answer

A)  bioluminesce. 
B)  form prosthecate and stalked cells. 
C)  fix nitrogen gas. 
D)  degrade neurotoxins. 
A)  bioluminesce. 
B)  form prosthecate and stalked cells. 
C)  fix nitrogen gas. 
D)  degrade neurotoxins.

Question 5

The Cyanobacteria are united by their ________, but their ________ is very diverse.

Accepted Answer

A)  physiology / morphology 
B)  morphology / physiology 
C)  ecology / physiology 
D)  SSU rRNA gene sequences / physiology 
A)  physiology / morphology 
B)  morphology / physiology 
C)  ecology / physiology 
D)  SSU rRNA gene sequences / physiology

Question 6

Bioluminescent microorganisms are found in which of the following groups?

Accepted Answer

A)  Firmicutes 
B)  Thaumarchaeota 
C)  Gammaproteobacteria 
D)  Verrucomicrobia 
A)  Firmicutes 
B)  Thaumarchaeota 
C)  Gammaproteobacteria 
D)  Verrucomicrobia

Question 7

What functional group (or groups) of microbes would be most useful in a microbial fuel cell in which electrons are transferred to and from solid metal electrodes? Why?

Accepted Answer

Iron-reducers and iron-oxidizers would b

Question 8

Considering the relationship between oxidizers and reducers, which of the following pairs of microorganisms are NOT likely to form close associations or consortia?

Accepted Answer

A)  purple sulfur bacteria and dissimilative sulfur-reducers 
B)  dissimilative sulfur-reducers and dissimilative sulfur-oxidizers 
C)  diazotrophs and fungi 
D)  nitrogen-fixing cyanobacteria and dissimilative sulfate-reducers 
A)  purple sulfur bacteria and dissimilative sulfur-reducers 
B)  dissimilative sulfur-reducers and dissimilative sulfur-oxidizers 
C)  diazotrophs and fungi 
D)  nitrogen-fixing cyanobacteria and dissimilative sulfate-reducers

Question 9

Anoxygenic phototrophs may or may not be autotrophs.

Accepted Answer

A) True 
 B)False

Question 10

Based on the FUNCTIONAL characteristics of the Cyanobacteria and Proteobacteria phyla, which phylum do you think is more deeply rooted in the tree of life (i.e., which phylum branches off closer to the last universal common ancestor)? Use at least two pieces of evidence to support your answer. How could you test your hypothesis?

Accepted Answer

Proteobacteria are more likely to be dee

Question 11

Purple sulfur bacteria are

Accepted Answer

A)  alphaproteobacteria that oxidize hydrogen sulfide in the presence of oxygen or nitrate. 
B)  gammaproteobacteria that use hydrogen sulfide as an electron donor for photosynthesis. 
C)  a phylogenetically heterogeneous group of microbes that reduce sulfate to sulfur. 
D)  thermophilic bacteria that reduce elemental sulfur to sulfide. 
A)  alphaproteobacteria that oxidize hydrogen sulfide in the presence of oxygen or nitrate. 
B)  gammaproteobacteria that use hydrogen sulfide as an electron donor for photosynthesis. 
C)  a phylogenetically heterogeneous group of microbes that reduce sulfate to sulfur. 
D)  thermophilic bacteria that reduce elemental sulfur to sulfide.

Question 12

Iron-reducing bacteria are obligately aerobic organisms that reduce ferric iron and oxidize hydrogen or organic compounds.

Accepted Answer

A) True 
 B)False

Question 13

In symbiotic associations between sulfur chemolithotrophs and eukaryotes such as tube worms and giant clams, the bacterial symbiont provides ________ while the host provides ________.

Accepted Answer

A)  nitrogen / carbon and oxygen 
B)  sulfide / oxygen 
C)  a carbon and energy source / stable sulfide and oxygen levels 
D)  organic acids / stable sulfate levels 
A)  nitrogen / carbon and oxygen 
B)  sulfide / oxygen 
C)  a carbon and energy source / stable sulfide and oxygen levels 
D)  organic acids / stable sulfate levels

Question 14

Nitrogenase is an oxygen-sensitive enzyme even though many diazotrophs are aerobic microorganisms.

Accepted Answer

A) True 
 B)False

Question 15

The Bacteria and Archaea are the ONLY domains in which organisms exist that can

Accepted Answer

A)  catalyze the transformation of inorganic nitrogen species for biosynthesis. 
B)  assimilate nitrite. 
C)  conserve energy from the transformation of inorganic nitrogen species. 
D)  catalyze the incorporation of inorganic nitrogen species into biomolecules. 
A)  catalyze the transformation of inorganic nitrogen species for biosynthesis. 
B)  assimilate nitrite. 
C)  conserve energy from the transformation of inorganic nitrogen species. 
D)  catalyze the incorporation of inorganic nitrogen species into biomolecules.

Question 16

Nitrogen fixation is

Accepted Answer

A)  rare among microorganisms. 
B)  widespread among microorganisms. 
C)  limited to Proteobacteria. 
D)  common in Bacteria, but absent in Archaea. 
A)  rare among microorganisms. 
B)  widespread among microorganisms. 
C)  limited to Proteobacteria. 
D)  common in Bacteria, but absent in Archaea.

Question 17

Bioluminescence is catalyzed by luciferase, which creates light by

Accepted Answer

A)  shunting electrons from FMNH₂ to O₂, which releases energy in the form of light. 
B)  reversing photosynthesis, which produces a surplus of ATP. 
C)  hydrolyzing ATP to release the excess energy as light. 
D)  reducing LuxR, the regulatory protein that controls the lux operon. 
A)  shunting electrons from FMNH₂ to O₂, which releases energy in the form of light. 
B)  reversing photosynthesis, which produces a surplus of ATP. 
C)  hydrolyzing ATP to release the excess energy as light. 
D)  reducing LuxR, the regulatory protein that controls the lux operon.

Question 18

Aerobic anoxygenic phototrophs

Accepted Answer

A)  do not use bacteriochlorophyll. 
B)  are an ancient monophyletic group of bacteria. 
C)  can be either autotrophic or heterotrophic. 
D)  cannot fix CO₂. 
A)  do not use bacteriochlorophyll. 
B)  are an ancient monophyletic group of bacteria. 
C)  can be either autotrophic or heterotrophic. 
D)  cannot fix CO₂.

Question 19

The ecological diversity of phototrophic bacteria is illustrated by the different ________ that allow them to perform photosynthesis in low light environments such as deep in the ocean, in various sediments, and in thick layered mats.

Accepted Answer

A)  nitrogen fixation strategies 
B)  bacteriochlorophyll and photosystems 
C)  specialized stalked cells 
D)  endospores and resistant cell types 
A)  nitrogen fixation strategies 
B)  bacteriochlorophyll and photosystems 
C)  specialized stalked cells 
D)  endospores and resistant cell types

Question 20

Akinetes and hormogonia are specialized cells, found in some cyanobacteria, that facilitate nitrogen fixation.

Accepted Answer

A) True 
 B)False

Exam 15: Functional Diversity of Microorganisms

Which of the following conditions would you use to enrich purple nonsulfur bacteria from lake sediments?

Which group of bacteria would you expect to find in a shallow clear hot spring with high concentrations of geochemically produced hydrogen sulfide?

Aside from using light as a source of energy, another important part of the functional diversity of some bacterial phototrophs is their ability to

The Cyanobacteria are united by their ________, but their ________ is very diverse.

Bioluminescent microorganisms are found in which of the following groups?

What functional group (or groups) of microbes would be most useful in a microbial fuel cell in which electrons are transferred to and from solid metal electrodes? Why?

Considering the relationship between oxidizers and reducers, which of the following pairs of microorganisms are NOT likely to form close associations or consortia?

Anoxygenic phototrophs may or may not be autotrophs.

Purple sulfur bacteria are

Iron-reducing bacteria are obligately aerobic organisms that reduce ferric iron and oxidize hydrogen or organic compounds.

In symbiotic associations between sulfur chemolithotrophs and eukaryotes such as tube worms and giant clams, the bacterial symbiont provides ________ while the host provides ________.

Nitrogenase is an oxygen-sensitive enzyme even though many diazotrophs are aerobic microorganisms.

The Bacteria and Archaea are the ONLY domains in which organisms exist that can

Nitrogen fixation is

Bioluminescence is catalyzed by luciferase, which creates light by

Aerobic anoxygenic phototrophs

The ecological diversity of phototrophic bacteria is illustrated by the different ________ that allow them to perform photosynthesis in low light environments such as deep in the ocean, in various sediments, and in thick layered mats.

Akinetes and hormogonia are specialized cells, found in some cyanobacteria, that facilitate nitrogen fixation.

The Microbial World

Microbial Cell Structure and Function

Microbial Metabolism

Molecular Information Flow and Protein Processing

Microbial Growth and Its Control

Microbial Regulatory Systems

Molecular Biology of Microbial Growth

Viruses and Their Replication

Microbial Systems Biology

Viral Genomics, Diversity, and Ecology

Genetics of Bacteria and Archaea

Biotechnology and Synthetic Biology

Microbial Evolution and Systematics

Metabolic Diversity of Microorganisms

Diversity of Bacteria

Diversity of Archaea

Diversity of Microbial Eukarya

Taking the Measure of Microbial Systems

Microbial Ecosystems

Nutrient Cycles

Microbiology of the Built Environment

Microbial Symbioses

Microbial Symbioses with Humans

Microbial Infection and Pathogenesis

Innate Immunity: Broadly Specific Host Defenses

Adaptive Immunity: Highly Specific Host Defenses

Clinical Microbiology and Immunology

Epidemiology

Person-to-Person Bacterial and Viral Diseases

Vectorborne and Soilborne Bacterial and Viral Diseases

Waterborne and Foodborne Bacterial and Viral Diseases

Eukaryotic Pathogens: Fungi, Protozoans, and Helminths

Filters

The Cyanobacteria are united by their , but their is very diverse.

In symbiotic associations between sulfur chemolithotrophs and eukaryotes such as tube worms and giant clams, the bacterial symbiont provides while the host provides .