Question 1

Intracytoplasmic membrane systems housing vesicles known as chromatophores,which function in photosynthesis,are commonly found in

Accepted Answer

A)  algae. 
B)  green sulfur bacteria. 
C)  most autotrophic organisms. 
D)  purple phototrophic bacteria. 
A)  algae. 
B)  green sulfur bacteria. 
C)  most autotrophic organisms. 
D)  purple phototrophic bacteria.

Question 2

Obligate anaerobes can often use ________ electropositive redox couples than facultative anaerobes,and ________ metabolism is most common in this group as well.

Accepted Answer

A)  lower / assimilative 
B)  lower / dissimilative 
C)  higher / assimilative 
D)  higher / dissimilative 
A)  lower / assimilative 
B)  lower / dissimilative 
C)  higher / assimilative 
D)  higher / dissimilative

Question 3

Fermentation of organic compounds,such as acetate,produces NADH and ATP.

Accepted Answer

A) True 
 B)False

Question 4

The conversion of light into chemical energy is called photoautotrophy.

Accepted Answer

A) True 
 B)False

Question 5

In most cases,the final product of sulfur oxidation is

Accepted Answer

A)  hydrogen sulfide. 
B)  elemental sulfur. 
C)  sulfate. 
D)  thiosulfate. 
A)  hydrogen sulfide. 
B)  elemental sulfur. 
C)  sulfate. 
D)  thiosulfate.

Question 6

The acetyl-CoA pathway is a primary route for carbon source utilization.

Accepted Answer

A) True 
 B)False

Question 7

Which of the following reactions is classified as a heterofermentation?

Accepted Answer

A)  hexose 2 lactate + 2 H⁺ 
B)  HCOOH H₂ + CO₂ 
C)  glucose lactate + ethanol + CO₂ + H⁺ 
D)  fructose 3 acetate + 3 H⁺ 
A)  hexose 2 lactate + 2 H⁺ 
B)  HCOOH H₂ + CO₂ 
C)  glucose lactate + ethanol + CO₂ + H⁺ 
D)  fructose 3 acetate + 3 H⁺

Question 8

The Calvin cycle

Accepted Answer

A)  is responsible for the fixation of CO₂ into cell material. 
B)  utilizes both NAD(P)H and ATP. 
C)  requires both ribulose bisphosphate carboxylase and phosphoribulokinase. 
D)  uses CO₂, NAD(P)H, and ATP to make biomass with ribulose bisphosphate carboxylase and phosphoribulokinase. 
A)  is responsible for the fixation of CO₂ into cell material. 
B)  utilizes both NAD(P)H and ATP. 
C)  requires both ribulose bisphosphate carboxylase and phosphoribulokinase. 
D)  uses CO₂, NAD(P)H, and ATP to make biomass with ribulose bisphosphate carboxylase and phosphoribulokinase.

Question 9

What metabolism would be favored when there is a lack of electron acceptors?

Accepted Answer

A)  anaerobic fermentation 
B)  anoxygenic photosynthesis 
C)  anoxic ammonia oxidation 
D)  acetogenesis 
A)  anaerobic fermentation 
B)  anoxygenic photosynthesis 
C)  anoxic ammonia oxidation 
D)  acetogenesis

Question 10

The path of electron flow in oxygenic phototrophs is referred to as the ________ scheme.

Accepted Answer

A)  E 
B)  S 
C)  Q 
D)  Z 
A)  E 
B)  S 
C)  Q 
D)  Z

Question 11

Organisms that aerobically catabolize methane use the intermediate ________ for biosynthesis and produce ________ when oxidizing the substrate for energy.

Accepted Answer

A)  CH₂O (formaldehyde) / CO 
B)  CH₂O (formaldehyde) / CO₂ 
C)  HCOO− (formate) / CO 
D)  HCOO− (formate) / CO₂ 
A)  CH₂O (formaldehyde) / CO 
B)  CH₂O (formaldehyde) / CO₂ 
C)  HCOO− (formate) / CO 
D)  HCOO− (formate) / CO₂

Question 12

Photooxidation reactions can lead to the production of toxic forms of oxygen and the destruction of the photosynthetic apparatus.

Accepted Answer

A) True 
 B)False

Question 13

Photosystem I is responsible for splitting a water molecule in the first step of oxygenic electron flow.

Accepted Answer

A) True 
 B)False

Question 14

The aerated upper layer of soil is likely to have ________ concentrations of H₂ for aerobic H₂-oxidizing Bacteria,so these bacteria likely ________.

Accepted Answer

A)  high / thrive in such conditions by not competing with chemoorganotrophs 
B)  high / generate important reducing equivalents as byproducts for other microorganisms in the soil 
C)  low / do not occur in such habitats 
D)  low / will need a chemoorganotrophic way to grow as well 
A)  high / thrive in such conditions by not competing with chemoorganotrophs 
B)  high / generate important reducing equivalents as byproducts for other microorganisms in the soil 
C)  low / do not occur in such habitats 
D)  low / will need a chemoorganotrophic way to grow as well

Question 15

Reaction centers ONLY indirectly receive photon energy via light-harvesting molecules.

Accepted Answer

A) True 
 B)False

Question 16

Despite being called the reverse citric acid cycle,it is currently identified as the most ancient autotrophic pathway.

Accepted Answer

A) True 
 B)False

Question 17

Regarding CO₂ fixation mechanisms in the autotrophic green sulfur bacteria,

Accepted Answer

A)  Chlorobium uses the reverse citric acid cycle, and Chloroflexus uses the hydroxypropionate pathway. 
B)  Chlorobium uses the hydroxypropionate pathway, and Chloroflexus uses the reverse citric acid cycle. 
C)  both Chlorobium and Chloroflexus use the reverse citric acid cycle. 
D)  both Chlorobium and Chloroflexus use the hydroxypropionate pathway. 
A)  Chlorobium uses the reverse citric acid cycle, and Chloroflexus uses the hydroxypropionate pathway. 
B)  Chlorobium uses the hydroxypropionate pathway, and Chloroflexus uses the reverse citric acid cycle. 
C)  both Chlorobium and Chloroflexus use the reverse citric acid cycle. 
D)  both Chlorobium and Chloroflexus use the hydroxypropionate pathway.

Question 18

A researcher lacked the necessary equipment to measure methane production so instead monitored CO₂ concentration as the unknown archaeon grew and produced methane.Why might CO₂ NOT decrease but methane still increase?

Accepted Answer

A)  An alternative carbon source such as methanol was used. 
B)  CO₂ is not a carbon source used by methanogens. 
C)  CO₂ was used an electron donor but not as a carbon substrate. 
D)  Methanogenic Archaea containing carboxysomes likely made measuring small losses of CO₂ difficult to conclude. 
A)  An alternative carbon source such as methanol was used. 
B)  CO₂ is not a carbon source used by methanogens. 
C)  CO₂ was used an electron donor but not as a carbon substrate. 
D)  Methanogenic Archaea containing carboxysomes likely made measuring small losses of CO₂ difficult to conclude.

Question 19

What metabolic advantage do cells have in storing the elemental sulfur byproduct from sulfide oxidation?

Accepted Answer

A)  The cells avoid producing transport energy waste to secrete the sulfur. 
B)  The byproduct serves as an electron reserve for subsequent oxidation. 
C)  Sulfur decreases the intracellular acidification for non-acid-tolerant sulfide oxidizers. 
D)  The byproduct can be used for other biosynthetic pathways that use sulfur, such as Rieske Fe-S proteins. 
A)  The cells avoid producing transport energy waste to secrete the sulfur. 
B)  The byproduct serves as an electron reserve for subsequent oxidation. 
C)  Sulfur decreases the intracellular acidification for non-acid-tolerant sulfide oxidizers. 
D)  The byproduct can be used for other biosynthetic pathways that use sulfur, such as Rieske Fe-S proteins.

Question 20

Why does an organism that is able to respire both aerobically and anaerobically preferentially undergo aerobic respiration?

Accepted Answer

Oxygen as the terminal electron acceptor

Exam 13: Metabolic Diversity of Microorganisms

Intracytoplasmic membrane systems housing vesicles known as chromatophores,which function in photosynthesis,are commonly found in

Obligate anaerobes can often use ________ electropositive redox couples than facultative anaerobes,and ________ metabolism is most common in this group as well.

Fermentation of organic compounds,such as acetate,produces NADH and ATP.

The conversion of light into chemical energy is called photoautotrophy.

In most cases,the final product of sulfur oxidation is

The acetyl-CoA pathway is a primary route for carbon source utilization.

Which of the following reactions is classified as a heterofermentation?

The Calvin cycle

What metabolism would be favored when there is a lack of electron acceptors?

The path of electron flow in oxygenic phototrophs is referred to as the ________ scheme.

Organisms that aerobically catabolize methane use the intermediate ________ for biosynthesis and produce ________ when oxidizing the substrate for energy.

Photooxidation reactions can lead to the production of toxic forms of oxygen and the destruction of the photosynthetic apparatus.

Photosystem I is responsible for splitting a water molecule in the first step of oxygenic electron flow.

The aerated upper layer of soil is likely to have ________ concentrations of H₂ for aerobic H₂-oxidizing Bacteria,so these bacteria likely ________.

Reaction centers ONLY indirectly receive photon energy via light-harvesting molecules.

Despite being called the reverse citric acid cycle,it is currently identified as the most ancient autotrophic pathway.

Regarding CO₂ fixation mechanisms in the autotrophic green sulfur bacteria,

A researcher lacked the necessary equipment to measure methane production so instead monitored CO₂ concentration as the unknown archaeon grew and produced methane.Why might CO₂ NOT decrease but methane still increase?

What metabolic advantage do cells have in storing the elemental sulfur byproduct from sulfide oxidation?

Why does an organism that is able to respire both aerobically and anaerobically preferentially undergo aerobic respiration?

Microorganisms and Microbiology

Microbial Cell Structure and Function

Microbial Metabolism

Molecular Biology

Microbial Growth and Control

Microbial Genomics

Metabolic Regulation

Viruses and Virology

Viral Genomes and Diversity

Genetics of Bacteria and Archaea

Genetic Engineering and Biotechnology

Microbial Evolution and Systematics

Functional Diversity of Bacteria

Diversity of Bacteria

Diversity of Archaea

Diversity of Eukaryotic Microorganisms

Methods in Microbial Ecology

Microbial Ecosystems

Nutrient Cycles

Microbiology of the Built Environment

Microbial Symbioses

Microbial Interactions With Humans

Immunity and Host Defense

Immune Mechanisms

Molecular Immunology

Diagnostic Microbiology

Epidemiology

Person-To-Person Bacterial and Viral Diseases

Vectorborne and Soilborne Bacterial and Viral Diseases

Water and Food As Vehicles of Bacterial Diseases

Eukaryotic Pathogens: Fungal and Parasitic Diseases

Filters

Obligate anaerobes can often use electropositive redox couples than facultative anaerobes,and metabolism is most common in this group as well.

Organisms that aerobically catabolize methane use the intermediate for biosynthesis and produce when oxidizing the substrate for energy.

The aerated upper layer of soil is likely to have concentrations of H₂ for aerobic H₂-oxidizing Bacteria,so these bacteria likely .