Deck 20: Microbial Ecosystems

Question 1

In a stratified lake, the warmer and less dense layer is called the

A) epilimnion.
B) hypolimnion.
C) hyperlimnion.
D) thermocline.

Answer 1

A

Question 2

Which is the correct order of increasing size in soil particles?

A) clay > sand > silt
B) clay > silt > sand
C) sand > clay > silt
D) silt > clay > sand

Answer 2

B

Question 3

Some nitrifying prokaryotes carry out metabolic cooperation by a process known as

A) competition.
B) niche partitioning.
C) syntrophy.
D) antagonism.

Answer 3

C

Question 4

The chemical oxygen demand (COD) of a body of water is determined using a(n)

A) microelectrode.
B) oxygenator.
C) spectrophotometer to determine the OD₅₄₀nm.
D) strong oxidizing agent.

Question 5

The abundance of cyanobacterial mats has greatly declined due to the evolution of

A) antimicrobial-producing fungi.
B) bacteriophages.
C) animal grazers.
D) Proteobacteria.

Question 6

A notorious biofilm former implicated in cystic fibrosis is

A) Bacillus subtilis.
B) Escherichia coli.
C) Lactobacillus acidophilus.
D) Pseudomonas aeruginosa.

Question 7

The photosynthetic pigments bacteriorhodopsin and proteorhodopsin are present in ________ and ________, respectively.

A) Archaea / Bacteria
B) Bacteria / Archaea
C) Bacteria / Bacteria
D) Bacteria / Eukarya

Question 8

According to bacterial abundance studies done so far on soils, the ________ represent the most abundant phylum.

A) Proteobacteria
B) Acidobacteria
C) Actinobacteria
D) Firmicutes

Question 9

A soil that lacks a dominate particle size is referred to as a(n)

A) aggregation.
B) bisequum.
C) loam.
D) mottled soil.

Question 10

Biofilm structure is determined by

A) nutritional factors.
B) signaling factors.
C) the local environment.
D) the local environment, nutritional factors, and signaling molecules.

Question 11

Which bacterial genus is responsible for producing ferrous iron (Fe²⁺) in groundwater?

A) Alteromonas
B) Aquifex
C) Geobacter
D) Loktanella

Question 12

An organism living in the bottommost region of a body of water is described as being

A) benthic.
B) litoral.
C) neritic.
D) pelagic.

Question 13

In the soil, oxygen concentrations are highly variable even within a soil particle. The center of the particle may be anoxic even if the outer portions are oxygen rich. In this context, facultative anaerobes could be found

A) at the surface of the particle.
B) in the center of the particle.
C) in the middle regions of the particle.
D) throughout the particle.

Question 14

A population consists of

A) all of the individuals of all species in the same area.
B) all of the individuals of one species in the same area.
C) all of the individuals that interact in different areas.
D) all of the individuals that interact in the same area.

Question 15

During periods of stratification, transfer between surface and bottom waters is controlled by

A) mixing.
B) diffusion.
C) niche partitioning.
D) current.

Question 16

The generation time of Escherichia coli in the human intestine is ________ in laboratory culture.

A) at about the same rate as
B) faster than
C) more optimal than
D) slower than

Question 17

Which of the following represents increasing microbial diversity?

A) guild-community-population
B) population-guild-community
C) cell-community-population
D) community-guild-population

Question 18

Which metabolic strategy is most common in chemolithotrophic mats?

A) ammonia oxidation
B) iron oxidation
C) nitrate reduction
D) sulfur oxidation

Question 19

Assuming exposure to the same climate, which of the following aquatic systems would be most stratified?

A) 20 m deep freshwater river
B) 50 m deep marine water fjord
C) 200 m deep saltwater lake
D) 300 m deep freshwater lake

Question 20

Which metric describes the proportion of EACH species present in a community?

A) species abundance
B) species diversity
C) species evenness
D) species richness

Question 21

From the aquatic systems below, where are heterotrophic Bacteria the most abundant?

A) marine coastal waters
B) deep sea
C) Sargasso Sea
D) open ocean

Question 22

Ecological theory states that for every organism there is at LEAST one ________, and the microenvironment where the organism is most successful is called the ________.

A) population / community
B) niche / prime niche
C) prime niche / niche
D) community / population

Question 23

The number of Roseobacter in the ocean describes

A) species diversity.
B) species richness.
C) species abundance.
D) species prevalence.

Question 24

Sudden nutrient perturbations in an environment generally ________ the overall prokaryotic diversity.

A) increase
B) decrease
C) maintain
D) replicate

Question 25

The primary metal sulfides emitted from the black smokers are ________ sulfides.

A) copper
B) iron
C) magnesium
D) zinc

Question 26

Epsilonproteobacteria are most dominant in hydrothermal vents because they

A) reduce nitrogen.
B) oxidize sulfide and sulfur as electron donors.
C) use oxygen as electron acceptors.
D) bind divalent cations.

Question 27

Which of the following is NOT an oxygenic phototrophic microorganism present in marine waters?

A) Ostreococcus
B) Prochlorococcus
C) Roseobacter
D) Trichodesmium

Question 28

In deep pelagic waters, the archaeal species present are almost all members of the

A) Crenarchaeota.
B) Euryarchaeota.
C) Nanoarchaeota.
D) Thaumarchaeota.

Question 29

Which are the most dominant chemolithotrophs in pelagic waters?

A) ammonia-oxidizing Archaea
B) ammonia-oxidizing Bacteria
C) sulfate-reducing Bacteria
D) Prochlorococcus

Question 30

All Prochlorococcus strains contain the pigments

A) chlorophylls a and b, but not phycobilins.
B) chlorophyll a and phycobilins, but not chlorophyll b.
C) chlorophyll b and phycobilins, but not chlorophyll a.
D) chlorophylls a and b and phycobilins.

Question 31

Phylogenetic analyses of marine prokaryotic diversity in both shallow and deep-sea marine sediments have found that both types of sediments are dominated by

A) Firmicutes.
B) Planctomycetes.
C) Proteobacteria.
D) Chloroflexi.

Question 32

Sedimentation in bogs and marshes develop ________ soils.

A) inorganic
B) mineral
C) organic
D) loamy

Question 33

What adaptation allows organisms to tolerate high pressures?

A) decreased cell size
B) decreased lipid content
C) increased ribosome size
D) increased unsaturated fatty acids

Question 34

Which statement is TRUE about the fluid from the hydrothermal vents?

A) The fluid contains large amounts of oxidized inorganic materials.
B) The fluid contains large amounts of reduced inorganic materials.
C) The fluid contains large amounts of organic material.
D) The fluid usually contains about equal amounts of organic and inorganic material.

Question 35

________ are the main primary producers in freshwater environments.

A) Phototrophic microorganisms
B) Heterotrophic microorganisms
C) Chemolithotrophic microorganisms
D) Viral microorganisms

Question 36

A chemical that comes from outside the ecosystem is referred to as a(n) ________ chemical.

A) synthropic
B) lithotrophic
C) allochthonous
D) pleomorphic

Question 37

A population of metabolically related microorganisms is called a(n)

A) guild.
B) niche.
C) ecosystem.
D) haplotype.

Question 38

How does the concentration of prokaryotic cells at the surface of pelagic water compare with the concentrations at depths below 1000 m?

A) There is a decrease in concentration from 1 m to 1000 m in depth, then a dramatic increase below 1000 m.
B) There is a decrease in concentration with increasing depth.
C) There is a steady increase in concentration with increasing depth.
D) There is an increase in concentration at depths below 1000 m.

Question 39

Which of the following is an example of a biofilm?

A) transient skin microbes
B) dental plaque
C) marine diatoms
D) a planktonic microcolony

Question 40

Which aquatic habitat contains a pelagic zone?

A) estuary
B) lake
C) salt marsh
D) open ocean

Question 41

Due to a vast array of nutrients, microorganisms are often capable of sustaining exponential growth in the environment.

Question 42

Chemoheterotrophic bacteria are primary producers.

Question 43

In the oceans, prokaryotes are greatly outnumbered by

A) zooplankton.
B) diatoms.
C) viruses.
D) phytoplankton.

Question 44

Cyclic dimeric guanosine monophosphate (c-di-GMP) serves as a messenger molecule in bacterial cells to coordinate a shift from ________ to ________ growth.

A) sessile / planktonic
B) planktonic / sessile
C) monomorphic / polymorphic
D) stationary / exponential

Question 45

The physiochemical conditions of a microenvironment, by definition, remain static.

Question 46

Two major environmental extremes of the deep sea are high ________ and low ________.

A) pressure / nutrient levels
B) nutrient levels / pressure
C) temperature / pressure
D) oxygen / pressure

Question 47

The microbial oxygen-consuming capacity of a water sample is called its

A) chemical oxygen demand.
B) biochemical capacity.
C) biochemical oxygen demand.
D) chemical capacity.

Question 48

Water in the rocks and soils of Earthʹs subsurface is called

A) groundwater.
B) surface water.
C) subsurface water.
D) deep water.

Question 49

Many microbial habitats are unsuitable for plants and animals.

Question 50

An ecosystem includes both the living organisms and abiotic materials that function together.

Question 51

Arid soils are among the most extreme environments on earth.

Question 52

Mineral soils largely come from weathered limestone and sand.

Question 53

The formation of soil involves a combination of biological, chemical, and physical processes.

Question 54

________ use inorganic electron donors released from deep-sea hydrothermal vents.

A) Chemolithotrophs
B) Photoheterotrophs
C) Chemoheterotrophs
D) Photolithotrophs

Question 55

Cyclic di-guanosine monophosphate is upregulated as Pseudomonas aeruginosa cells are declining.

Question 56

Biomass generation due to heterotrophic organisms is called ________ production.

A) primary
B) secondary
C) auxotrophic
D) regulatory

Question 57

The cells within a biofilm can undergo intra-species signaling; however, inter-species signaling does not occur.

Question 58

Cells within a biofilm excrete an adhesive matrix primarily composed of ________ but can also contain nucleic acids as well as proteins.

A) lipids
B) fatty acids
C) monomers
D) polysaccharides

Question 59

The most abundant prokaryotic organism in the ocean is of the ________ genus.

A) Pelagibacter
B) Puniceispirillum
C) Roseobacter
D) Prochlorococcus

Question 60

A microbial population can contain several microbial communities.

Question 61

Purple phototrophic bacteria that use bacteriochlorophyll a are oxygenic.

Question 62

Chemoorganotrophic bacteria can facilitate the formation of soil through the secretion of organic acids.

Question 63

Explain how both biochemical oxygen demand and chemical oxygen demand are measured.

Question 64

What is the difference between an organism being piezophilic and piezotolerant?

Question 65

Distinguish an ecotype from a species, and provide an example of an ecotype.

Question 66

Provide a reason for the ecological importance of pelagic Bacteria and Archaea.

Question 67

Explain three reasons why bacteria form biofilms.

Question 68

Soil particles are classified based on their size.

Question 69

Describe three molecular effects high pressure has on the physiology of organisms.

Question 70

All stratified lakes contain a thermocline.

Question 71

Functional differences can be observed by using 16S rRNA gene phylogenetics of a microbial community.

Question 72

In the context of nutrients, a sink is one that slowly releases a particular nutrient over time.

Question 73

In many marine systems, the carbon and oxygen cycles are directly proportional to each other.

Question 74

Gammaproteobacteria can be used for biodegradation of hydrocarbons.

Question 75

Limiting nutrients in soils are generally organic compounds.

Question 76

Microbial life has been identified at depths of 3 km despite being anoxic.

Question 77

Oligotrophic organisms do NOT grow well under nutrient-replete conditions.

Question 78

Low return of nutrients in the pelagic zone results in relatively low primary production in the open ocean when compared to freshwater lake systems.

Question 79

Unlike other cyanobacteria, Prochlorococcus lacks phycobilins.

Question 80

Archaea and Bacteria dominate the upper 100 m of the open ocean while viruses dominate depths greater than 100 m.