Question 1

Which statement describes the relationship between ammonia oxidizers and nitrite oxidizers?

Accepted Answer

A)  Ammonium oxidizers use ammonium as an energy source, oxidizing it to nitrite. The nitrite produced then serves as the energy source for nitrite oxidizers. 
B)  Ammonium oxidizers use ammonium as an energy source, oxidizing it to nitrate. The nitrate produced then serves as the energy source for nitrite oxidizers. 
C)  Ammonium oxidizers use urea as an energy source, oxidizing it to nitrite. The nitrite produced then serves as the carbon source for nitrite oxidizers. 
D)  Ammonium oxidizers use ammonium as an energy source, reducing it to nitrate. The nitrate produced then serves as the energy source for nitrite oxidizers. 
E)  None of these explains the relationship-ammonia and nitrite are produced by different nutrient cycles which also involve sulfur reduction. 
A)  Ammonium oxidizers use ammonium as an energy source, oxidizing it to nitrite. The nitrite produced then serves as the energy source for nitrite oxidizers. 
B)  Ammonium oxidizers use ammonium as an energy source, oxidizing it to nitrate. The nitrate produced then serves as the energy source for nitrite oxidizers. 
C)  Ammonium oxidizers use urea as an energy source, oxidizing it to nitrite. The nitrite produced then serves as the carbon source for nitrite oxidizers. 
D)  Ammonium oxidizers use ammonium as an energy source, reducing it to nitrate. The nitrate produced then serves as the energy source for nitrite oxidizers. 
E)  None of these explains the relationship-ammonia and nitrite are produced by different nutrient cycles which also involve sulfur reduction.

Question 2

Which of the following soil organisms play a major role in decomposing plant matter?

Accepted Answer

A)  bacteria AND fungi 
B)  bacteria AND viruses 
C)  fungi AND protozoa 
D)  protozoa AND viruses 
E)  viruses AND fungi 
A)  bacteria AND fungi 
B)  bacteria AND viruses 
C)  fungi AND protozoa 
D)  protozoa AND viruses 
E)  viruses AND fungi

Question 3

The term used to describe the interrelationship between the living and non-living environments in an area is called a(n)

Accepted Answer

A)  group. 
B)  community. 
C)  ecosystem. 
D)  ecological niche. 
E)  habitat. 
A)  group. 
B)  community. 
C)  ecosystem. 
D)  ecological niche. 
E)  habitat.

Question 4

What is the likely fate of a fish living in a eutrophic stream?

Accepted Answer

A)  Fish will first thrive as they have more oxygen from the increase in photosynthetic organisms; eutrophic streams are low in nutrients however, so they will quickly die. 
B)  Eutrophic streams have high levels of carbon dioxide. Fish will be able to use this for aerobic respiration, so will thrive in this environment. 
C)  Eutrophic streams are always anoxic. This means that only anaerobic fish will be able to survive in a eutrophic environment. 
D)  Fish will first thrive as they have more food from the increase in photosynthetic organisms; as they deplete the dissolved oxygen, however, they will die. 
E)  Eutrophic streams have low levels of nutrients in them. Only fish that feed off other fish will be able to survive in these streams. 
A)  Fish will first thrive as they have more oxygen from the increase in photosynthetic organisms; eutrophic streams are low in nutrients however, so they will quickly die. 
B)  Eutrophic streams have high levels of carbon dioxide. Fish will be able to use this for aerobic respiration, so will thrive in this environment. 
C)  Eutrophic streams are always anoxic. This means that only anaerobic fish will be able to survive in a eutrophic environment. 
D)  Fish will first thrive as they have more food from the increase in photosynthetic organisms; as they deplete the dissolved oxygen, however, they will die. 
E)  Eutrophic streams have low levels of nutrients in them. Only fish that feed off other fish will be able to survive in these streams.

Question 5

Streptomyces produces geosmins which give soil a characteristic musty odor.

Accepted Answer

A) True 
 B)False

Question 6

Eutrophic waters

Accepted Answer

A)  are nutrient rich AND contain 3.5% salt. 
B)  may become hypoxic AND lack phosphate, nitrate, and iron. 
C)  lack phosphate, nitrate, and iron AND contain 3.5% salt. 
D)  contain 3.5% salt AND are alkaline. 
E)  are nutrient rich AND may become hypoxic. 
A)  are nutrient rich AND contain 3.5% salt. 
B)  may become hypoxic AND lack phosphate, nitrate, and iron. 
C)  lack phosphate, nitrate, and iron AND contain 3.5% salt. 
D)  contain 3.5% salt AND are alkaline. 
E)  are nutrient rich AND may become hypoxic.

Question 7

The role that an organism plays in its environment is called its

Accepted Answer

A)  role. 
B)  niche. 
C)  position. 
D)  ecosystem. 
E)  habit. 
A)  role. 
B)  niche. 
C)  position. 
D)  ecosystem. 
E)  habit.

Question 8

Gardeners sometimes plant clover between productive growing seasons. Why would this practice be beneficial?

Accepted Answer

A)  Several types of nitrogen-fixing bacteria form a symbiotic relationship with the roots of clover. This would increase the amount of nitrogen in the soil available for subsequent seasons of other plants' growth. 
B)  Clover is consumed by a number of animals. This would encourage the animals to feed/graze on the areas, leaving behind nitrogen-rich manure (feces) that would act as a natural fertilizer for subsequent seasons of other plants' growth. 
C)  Clover is a unique plant that is capable of atmospheric nitrogen-fixation (pulling nitrogen directly out of the air and turning it into ammonia or amino acids). This directly provides nitrogen compounds for the soil for subsequent seasons of other plants' growth. 
D)  The beneficial effect is more for water retention and elimination of soil erosion in between growing seasons than for any nutrient value. It has nothing to do with nitrogen compounds in the soil. 
E)  Several types of oxygen-fixing bacteria form a symbiotic relationship with the roots of clover. This would increase the amount of oxygen in the soil available for subsequent seasons of other plants' growth. 
A)  Several types of nitrogen-fixing bacteria form a symbiotic relationship with the roots of clover. This would increase the amount of nitrogen in the soil available for subsequent seasons of other plants' growth. 
B)  Clover is consumed by a number of animals. This would encourage the animals to feed/graze on the areas, leaving behind nitrogen-rich manure (feces) that would act as a natural fertilizer for subsequent seasons of other plants' growth. 
C)  Clover is a unique plant that is capable of atmospheric nitrogen-fixation (pulling nitrogen directly out of the air and turning it into ammonia or amino acids). This directly provides nitrogen compounds for the soil for subsequent seasons of other plants' growth. 
D)  The beneficial effect is more for water retention and elimination of soil erosion in between growing seasons than for any nutrient value. It has nothing to do with nitrogen compounds in the soil. 
E)  Several types of oxygen-fixing bacteria form a symbiotic relationship with the roots of clover. This would increase the amount of oxygen in the soil available for subsequent seasons of other plants' growth.

Question 9

The organisms that obtain energy by oxidation of hydrogen sulfide and use carbon dioxide as a carbon source are called

Accepted Answer

A)  heterotrophs. 
B)  chemolithoautotrophs. 
C)  chemoheterotrophs. 
D)  autotrophs. 
E)  chemoliths. 
A)  heterotrophs. 
B)  chemolithoautotrophs. 
C)  chemoheterotrophs. 
D)  autotrophs. 
E)  chemoliths.

Question 10

The organisms that convert carbon dioxide into organic matter are the

Accepted Answer

A)  secondary consumers. 
B)  primary consumers. 
C)  producers. 
D)  decomposers. 
E)  secondary decomposers. 
A)  secondary consumers. 
B)  primary consumers. 
C)  producers. 
D)  decomposers. 
E)  secondary decomposers.

Question 11

What gene sequences are used to identify the prokaryote organisms present in an environmental sample?

Accepted Answer

A)  18S rRNA genes 
B)  16S rRNA genes 
C)  70S rRNA genes 
D)  80S rRNA genes 
E)  All of these 
A)  18S rRNA genes 
B)  16S rRNA genes 
C)  70S rRNA genes 
D)  80S rRNA genes 
E)  All of these

Question 12

Please select the correct sequence of steps involved in the creation of a dead zone in a water body.
1) Heterotrophic microbes metabolize the organic compounds synthesized by primary producers.
2) Water becomes hypoxic and toxic algal blooms may occur; animals in the area either flee or die.
3) Water accumulates nutrients as it runs through agricultural, industrial, and urbanized regions.
4) Dissolved O₂ is consumed by metabolic activity of heterotrophs.
5) Excess nitrate and phosphate in nutrient-rich water causes algae and cyanobacteria to flourish.

Accepted Answer

A)  3; 5; 1; 4; 2 
B)  3; 1; 4; 2; 5 
C)  1; 3; 4; 2; 5 
D)  5; 3; 4; 2; 1 
E)  2; 1; 4; 3; 5 
A)  3; 5; 1; 4; 2 
B)  3; 1; 4; 2; 5 
C)  1; 3; 4; 2; 5 
D)  5; 3; 4; 2; 1 
E)  2; 1; 4; 3; 5

Question 13

Streptomyces

Accepted Answer

A)  may produce antibiotics. 
B)  may produce antivirals. 
C)  are typically found in the air. 
D)  are frequently transmitted by vectors. 
E)  will swarm together to form fruiting bodies. 
A)  may produce antibiotics. 
B)  may produce antivirals. 
C)  are typically found in the air. 
D)  are frequently transmitted by vectors. 
E)  will swarm together to form fruiting bodies.

Question 14

The organisms found near warm vents on the bottom of the ocean are typically chemoautotrophic.

Accepted Answer

A) True 
 B)False

Question 15

Explain how nutrient-rich runoff can cause waters to become hypoxic.

Accepted Answer

A)  Algae and cyanobacteria flourish on the nutrients in the runoff. Heterotrophic microbes then flourish on the organic molecules produced by these organisms, using oxygen in the process and leading to a hypoxic state in the area. Larger animals cannot survive in the hypoxic area. 
B)  Algae and cyanobacteria flourish on the nutrients in the runoff, using oxygen in the process. This consumption of oxygen leads to a hypoxic state in the area. Larger animals cannot survive in the hypoxic area. 
C)  The nutrients in the runoff often include chemicals that spontaneously oxidize in the presence of oxygen. They tend to deplete the amount of oxygen present in an area simply by being present themselves. This consumption of oxygen leads to a hypoxic state in the area. Larger animals cannot survive in the hypoxic area. 
D)  The nutrients in the runoff often include toxic chemicals that kill anaerobes such as cyanobacteria. Aerobes flourish, depleting the amount of oxygen present. This consumption of oxygen leads to a hypoxic state in the area. Larger animals cannot survive in the hypoxic area. 
E)  It doesn't. This claim is a scare tactic used by environmental extremists to prevent farmers and individuals from fertilizing their crops and lawns. There is no induction of a hypoxic state in bodies of water where runoff occurs. 
A)  Algae and cyanobacteria flourish on the nutrients in the runoff. Heterotrophic microbes then flourish on the organic molecules produced by these organisms, using oxygen in the process and leading to a hypoxic state in the area. Larger animals cannot survive in the hypoxic area. 
B)  Algae and cyanobacteria flourish on the nutrients in the runoff, using oxygen in the process. This consumption of oxygen leads to a hypoxic state in the area. Larger animals cannot survive in the hypoxic area. 
C)  The nutrients in the runoff often include chemicals that spontaneously oxidize in the presence of oxygen. They tend to deplete the amount of oxygen present in an area simply by being present themselves. This consumption of oxygen leads to a hypoxic state in the area. Larger animals cannot survive in the hypoxic area. 
D)  The nutrients in the runoff often include toxic chemicals that kill anaerobes such as cyanobacteria. Aerobes flourish, depleting the amount of oxygen present. This consumption of oxygen leads to a hypoxic state in the area. Larger animals cannot survive in the hypoxic area. 
E)  It doesn't. This claim is a scare tactic used by environmental extremists to prevent farmers and individuals from fertilizing their crops and lawns. There is no induction of a hypoxic state in bodies of water where runoff occurs.

Question 16

Which of the following refers to a symbiotic association between plant roots and fungi?

Accepted Answer

A)  Lichens 
B)  Geosmins 
C)  Extremophiles 
D)  Ant gardens 
E)  Mycorrhizae 
A)  Lichens 
B)  Geosmins 
C)  Extremophiles 
D)  Ant gardens 
E)  Mycorrhizae

Question 17

A microbial mat

Accepted Answer

A)  is a form of biofilm. 
B)  is poorly organized. 
C)  contains only obligate anaerobes. 
D)  is constructed to prevent interactions between the various layers of microorganisms. 
E)  is a form of biofilm AND is poorly organized. 
A)  is a form of biofilm. 
B)  is poorly organized. 
C)  contains only obligate anaerobes. 
D)  is constructed to prevent interactions between the various layers of microorganisms. 
E)  is a form of biofilm AND is poorly organized.

Question 18

In many aquatic habitats, the growth of algae and cyanobacteria is limited by the amount of

Accepted Answer

A)  nitrogen. 
B)  phosphorus. 
C)  calcium. 
D)  sulfur. 
E)  nitrites. 
A)  nitrogen. 
B)  phosphorus. 
C)  calcium. 
D)  sulfur. 
E)  nitrites.

Question 19

Atmospheric nitrogen is

Accepted Answer

A)  used directly by plants. 
B)  used directly by animals. 
C)  turned into ammonia by microorganisms. 
D)  directly used to make carbohydrates. 
E)  converted into urea by bacteria. 
A)  used directly by plants. 
B)  used directly by animals. 
C)  turned into ammonia by microorganisms. 
D)  directly used to make carbohydrates. 
E)  converted into urea by bacteria.

Question 20

The problem of not being able to cultivate most microorganisms has led to the use of

Accepted Answer

A)  FISH. 
B)  microscopy with fluorescent dyes. 
C)  16s rRNA analysis. 
D)  FISH and 16s rRNA analysis. 
E)  All of these methods help identify microorganisms in the environment. 
A)  FISH. 
B)  microscopy with fluorescent dyes. 
C)  16s rRNA analysis. 
D)  FISH and 16s rRNA analysis. 
E)  All of these methods help identify microorganisms in the environment.

Exam 28: Microbial Ecology

Which statement describes the relationship between ammonia oxidizers and nitrite oxidizers?

Which of the following soil organisms play a major role in decomposing plant matter?

The term used to describe the interrelationship between the living and non-living environments in an area is called a(n)

What is the likely fate of a fish living in a eutrophic stream?

Streptomyces produces geosmins which give soil a characteristic musty odor.

Eutrophic waters

The role that an organism plays in its environment is called its

Gardeners sometimes plant clover between productive growing seasons. Why would this practice be beneficial?

The organisms that obtain energy by oxidation of hydrogen sulfide and use carbon dioxide as a carbon source are called

The organisms that convert carbon dioxide into organic matter are the

What gene sequences are used to identify the prokaryote organisms present in an environmental sample?

Streptomyces

The organisms found near warm vents on the bottom of the ocean are typically chemoautotrophic.

Explain how nutrient-rich runoff can cause waters to become hypoxic.

Which of the following refers to a symbiotic association between plant roots and fungi?

A microbial mat

In many aquatic habitats, the growth of algae and cyanobacteria is limited by the amount of

Atmospheric nitrogen is

The problem of not being able to cultivate most microorganisms has led to the use of

Humans and the Microbial World

The Molecules of Life

Microscopy and Cell Structure

Dynamics of Microbial Growth

Control of Microbial Growth

Microbial Metabolism: Fueling Cell Growth

The Blueprint of Life, from DNA to Protein

Bacterial Genetics

Biotechnology

Identifying and Classifying Microorganisms

The Diversity of Bacteria and Archaea

The Eukaryotic Members of the Microbial World

Viruses, Viroids, and Prions

The Innate Immune Response

The Adaptive Immune Response

Host-Microbe Interactions

Immunological Disorders

Applications of Immune Responses

Epidemiology

Antimicrobial Medications

Respiratory System Infections

Skin Infections

Wound Infections

Digestive System Infections

Blood and Lymphatic Infections

Nervous System Infections

Genitourinary Tract Infections

Environmental Microbiology: Treatment of Water, Wastes, and Polluted Habitats

Food Microbiology

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