Question 1

Which of the following substrates is an electron donor in organotrophy?

Accepted Answer

A)  Fe2+ 
B)  succinate 
C)  NO2 
D)  H2 
E)  H2O 
A)  Fe2+ 
B)  succinate 
C)  NO2 
D)  H2 
E)  H2O B

Question 2

What are methanotrophs? What is their role in the global carbon cycle?

Accepted Answer

Methanotrophs are organisms that oxidize methane using oxygen or another inorganic compound as a terminal electron acceptor. Methanogens provide an abundance of methane, which can be harvested by methanotrophs. On the ocean floor, methane becomes trapped, and anaerobic methane oxidation plays a critical role in the global carbon cycle, removing submarine methane. Previously, it was thought that methanotrophy was only associated with aerobic oxidation.

Question 3

Explain what kind of reaction bacteriorhodopsin performs and what it accomplishes for the cell. What is the name of the bacteriorhodopsin homologs, in what type of organisms were they identified, and what led to their discovery?

Accepted Answer

Bacteriorhodopsin absorbs light and goes through a photocycle involving excitation and relaxation and ultimately resulting in the pumping of one H⁺. This generates a proton motive force that can be used for ATP synthesis. Bacteriorhodopsin was thought to be limited to extreme halophilic archaea. In 2005, several researchers collected samples of seawater from the Mediterranean and Red seas. A community genome analysis was performed, including analysis of unculturable bacteria. The genomes from 13% of the marine bacteria were found to contain bacteriorhodopsin homologs, which were termed proteorhodopsins. Thus, a sizable proportion of marine phototrophy can be attributed to proteorhodopsin-producing organisms.

Question 4

Extreme halophilic archaea exclusively utilize which kind of ion gradient?

Accepted Answer

A)  H+ 
B)  Na+ 
C)  Ca2+ 
D)  K+ 
E)  Mg2+ 
A)  H+ 
B)  Na+ 
C)  Ca2+ 
D)  K+ 
E)  Mg2+

Question 5

In anaerobic soils, some yeasts and filamentous fungi can reduce nitrate to nitrite and nitrite to

Accepted Answer

A)  ammonia (NH3). 
B)  nitric oxide (NO). 
C)  urea. 
D)  nitrogen gas (N2). 
E)  ammonium hydroxide (NH4OH). 
A)  ammonia (NH3). 
B)  nitric oxide (NO). 
C)  urea. 
D)  nitrogen gas (N2). 
E)  ammonium hydroxide (NH4OH).

Question 6

Sulfolobus species produce __________; as a result, their immediate environment has a pH __________.

Accepted Answer

A)  H2SO4; as low as 2 
B)  H3PO4; as low as 3 
C)  HCl; of 1 
D)  CH3COOH; of 4 
E)  HCOOH; of 3 
A)  H2SO4; as low as 2 
B)  H3PO4; as low as 3 
C)  HCl; of 1 
D)  CH3COOH; of 4 
E)  HCOOH; of 3

Question 7

The organism __________ is also known as "the bacterium that eats everything." It conducts photoheterotrophy and fixes nitrogen as ammonium while generating H₂. It also produces ATP via cyclic photophosphorylation in photosystem II.

Accepted Answer

A)  Pseudochrobactrum saccharolyticum 
B)  Nitrobacter winogradskyi 
C)  Bradyrhizobium japonicum 
D)  Rhodopseudomonas palustris 
E)  Brucella pinnipedialis 
A)  Pseudochrobactrum saccharolyticum 
B)  Nitrobacter winogradskyi 
C)  Bradyrhizobium japonicum 
D)  Rhodopseudomonas palustris 
E)  Brucella pinnipedialis

Question 8

Describe the role of the thylakoids in purple bacteria and cyanobacteria. Why is it that pumping protons into the lumen is essentially equivalent to pumping protons out of the cell?

Accepted Answer

In bacteria, thylakoids are invagination

Question 9

What factors may affect ∆p in metabolically active bacterial cells?

Accepted Answer

@#LAT-DLM&p depends on the membrane potential (@#LAT-DLM& an

Question 10

Which species can be utilized in biomining because it oxidizes copper and iron sulfides?

Accepted Answer

A)  Geobacter metallireducens 
B)  Sulfurospirillum barnesii 
C)  Haloferax volcanii 
D)  Acidithiobacillus ferrooxidans 
E)  Bacillus subtilis 
A)  Geobacter metallireducens 
B)  Sulfurospirillum barnesii 
C)  Haloferax volcanii 
D)  Acidithiobacillus ferrooxidans 
E)  Bacillus subtilis

Question 11

Use the figure below to describe Salmonella enterica respiration on tetrathionate. What is the advantage of using this anaerobic respiratory mechanism?

Accepted Answer

[i] Salmonella enterica invades epitheli

Question 12

How does bacteriorhodopsin couple photoexcitation with proton pumping? How is ATP synthesized in bacteriorhodopsin-containing organisms?

Accepted Answer

Bacteriorhodopsin is an integral membran

Question 13

11
-Which of the reactions below is written in the direction "electron acceptor $ \rightarrow $ electron donor"?
a. ubiquinone $ +2 \mathrm{H}^{+}+2 \mathrm{e}^{-} \rightarrow $ ubiquinone
b. $ \mathrm{Fe}^{2+} \rightarrow \mathrm{Fe}^{3+}+\mathrm{e}^{-} $
c. $ \mathrm{FADH}_{2} \rightarrow \mathrm{FAD}+2 \mathrm{H}^{+}+2 \mathrm{e}^{-} $
d. Glucose $ +\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{CO}_{2}+4 \mathrm{H}^{+}+4 \mathrm{e}^{-} $
e. $ \mathrm{HS}^{-} \rightarrow \mathrm{S}^{0}+\mathrm{H}^{+}+2 \mathrm{e} $

Accepted Answer

The answer of 11
-Which of the reactions below is written...

Question 14

Use the figure below to describe how Acidithiobacillus ferrooxidans can utilize iron as an electron donor for ATP production. Discuss how other microbes benefit from or contribute to the process.

Accepted Answer

Acidithiobacillus ferrooxidans bacteria

Question 15

Ferroplasma acidarmanus produces large amounts of sulfuric acid through

Accepted Answer

A)  oxidation of Cu+ with Cu(NO3)2. 
B)  oxidation of FeS2 with Fe3+ and H2O. 
C)  oxidation of Fe3O2 with Fe2+. 
D)  oxidation of H2S with H2O. 
E)  reduction of SO with H2. 
A)  oxidation of Cu+ with Cu(NO3)2. 
B)  oxidation of FeS2 with Fe3+ and H2O. 
C)  oxidation of Fe3O2 with Fe2+. 
D)  oxidation of H2S with H2O. 
E)  reduction of SO with H2.

Question 16

The chlorophyll chromophore consists of a heteroaromatic ring complexed to a __________ ion.

Accepted Answer

A)  calcium 
B)  chloride 
C)  magnesium 
D)  manganese 
E)  potassium 
A)  calcium 
B)  chloride 
C)  magnesium 
D)  manganese 
E)  potassium

Question 17

Which of the following reactions is possible by reverse electron flow?

Accepted Answer

A)  reduction of Fe3+ to Fe2+ 
B)  NADP+ reduction to NADPH 
C)  protein biosynthesis 
D)  reduction of oxygen by Fe2+ to form H2O and Fe3+ 
E)  anammox 
A)  reduction of Fe3+ to Fe2+ 
B)  NADP+ reduction to NADPH 
C)  protein biosynthesis 
D)  reduction of oxygen by Fe2+ to form H2O and Fe3+ 
E)  anammox

Question 18

Is the synthesis of ATP by the F₁Fₒ ATPase reversible? If so, are there any examples?

Accepted Answer

Generation of ATP by the F₁Fₒ ATPase is

Question 19

Which of the following definitions is FALSE?

Accepted Answer

A)  Photosynthesis is hotolysis followed by CO2 fixation and biosynthesis. 
B)  Photolysis is light absorption coupled to splitting of a molecule. 
C)  Photophosphorylation is the reaction ADP + Pi $$\rightarrow$$ ATP catalyzed by photons. 
D)  Photoexcitation is light absorption causing an electron to transfer to a higher energy state. 
E)  Photoionization is light absorption that causes electron separation. 
A)  Photosynthesis is hotolysis followed by CO2 fixation and biosynthesis. 
B)  Photolysis is light absorption coupled to splitting of a molecule. 
C)  Photophosphorylation is the reaction ADP + Pi $$\rightarrow$$ ATP catalyzed by photons. 
D)  Photoexcitation is light absorption causing an electron to transfer to a higher energy state. 
E)  Photoionization is light absorption that causes electron separation.

Question 20

In marine sediments, CO₂ is reduced to CH₄ by

Accepted Answer

A)  bacteria containing proteorhodopsin. 
B)  oxygenic cyanobacteria. 
C)  methanotrophic archaea. 
D)  methanogenic archaea. 
E)  nonpurple sulfur bacteria. 
A)  bacteria containing proteorhodopsin. 
B)  oxygenic cyanobacteria. 
C)  methanotrophic archaea. 
D)  methanogenic archaea. 
E)  nonpurple sulfur bacteria.

Exam 14: Electron Flow in Organotrophy, Lithotrophy, and Phototrophy

Which of the following substrates is an electron donor in organotrophy?

What are methanotrophs? What is their role in the global carbon cycle?

Explain what kind of reaction bacteriorhodopsin performs and what it accomplishes for the cell. What is the name of the bacteriorhodopsin homologs, in what type of organisms were they identified, and what led to their discovery?

Extreme halophilic archaea exclusively utilize which kind of ion gradient?

In anaerobic soils, some yeasts and filamentous fungi can reduce nitrate to nitrite and nitrite to

Sulfolobus species produce __________; as a result, their immediate environment has a pH __________.

The organism __________ is also known as "the bacterium that eats everything." It conducts photoheterotrophy and fixes nitrogen as ammonium while generating H₂. It also produces ATP via cyclic photophosphorylation in photosystem II.

Describe the role of the thylakoids in purple bacteria and cyanobacteria. Why is it that pumping protons into the lumen is essentially equivalent to pumping protons out of the cell?

What factors may affect ∆p in metabolically active bacterial cells?

Which species can be utilized in biomining because it oxidizes copper and iron sulfides?

Use the figure below to describe Salmonella enterica respiration on tetrathionate. What is the advantage of using this anaerobic respiratory mechanism?

How does bacteriorhodopsin couple photoexcitation with proton pumping? How is ATP synthesized in bacteriorhodopsin-containing organisms?

Use the figure below to describe how Acidithiobacillus ferrooxidans can utilize iron as an electron donor for ATP production. Discuss how other microbes benefit from or contribute to the process.

Ferroplasma acidarmanus produces large amounts of sulfuric acid through

The chlorophyll chromophore consists of a heteroaromatic ring complexed to a __________ ion.

Which of the following reactions is possible by reverse electron flow?

Is the synthesis of ATP by the F₁Fₒ ATPase reversible? If so, are there any examples?

Which of the following definitions is FALSE?

In marine sediments, CO₂ is reduced to CH₄ by

Microbial Life: Origin and Discovery

Observing the Microbial Cell

Cell Structure and Function

Bacterial Culture, Growth, and Development

Environmental Influences and Control of Microbial Growth

Viruses

Genomes and Chromosomes

Transcription, Translation, and Bioinformatics

Gene Transfer, Mutations, and Genome Evolution

Molecular Regulation

Viral Molecular Biology

Biotechniques and Synthetic Biology

Energetics and Catabolism

Biosynthesis

Food and Industrial Microbiology

Origins and Evolution

Bacterial Diversity

Archaeal Diversity

Eukaryotic Diversity

Microbial Ecology

Microbes in Global Elemental Cycles

Human Microbiota and Innate Immunity

The Adaptive Immune Response

Microbial Pathogenesis

Microbial Diseases

Antimicrobial Therapy

Clinical Microbiology and Epidemiology

Filters

Sulfolobus species produce ; as a result, their immediate environment has a pH .