Module 4 - Microbial Ecosystems Flashcards

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1
Q

The specific functional role of an organism within an ecosystem is called?

A

Niche

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2
Q

What are the 3 factors pertaining to resources that help define a niche?

A
  • Type
  • Quality
  • Quantity
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3
Q

What is the general rule in ecology?

A

No two populations of organisms can occupy the same niche and co-exist sustainably

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4
Q

Which archaeal and bacterial pair can coexist stably within the same gut habitats?

A

Methanobrevibacter smithii and E.coli

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5
Q

E.coli is the … in the colon

A

Fermenter

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6
Q

M. smithii is a … in the colon

A

Methanogen

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7
Q

Structured communities held together by extracellular polysaccharides are called?

A

Biofilms

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8
Q

How does biofilm growth provide an advantage for microorganisms?

A

Nutrients bind to solid surfaces; enables higher cell concentrations

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9
Q

What are the first microorganisms adhering to a surface? Give an example

A
  • Appendaged bacteria

- Caulobacter or Hyphomicrobium

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10
Q

Species that divide and form microcolonies are called?

A

Primary colonizers

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11
Q

Species that join the growing biofilms are called?

A

Secondary colonizers

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12
Q

What forms a gel-like matrix that is important for biofilm formation?

A

Exopolyssacharides (EPS)

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13
Q

What are the functions of the gel-like matrix?

A
  • Aids in the formation of water-filled channels

- Facilitates the transport of nutrients and waste through the biofilm

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14
Q

Using a culture medium and conditions designed to favor the growth of a particular microorganisms is called?

A

Cultivation-Dependent Techniques

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15
Q

What is the name of the aerobic N2-fixing bacteria?

A

Azotobacter

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16
Q

Characterizing inhabitants of microbial ecosystems, including microorganisms that we cannot grow readily are called?

A

Cultivation-Independent Techniques

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17
Q

Minerals, gases, and water are known as what kind of factors?

A

Abiotic factors

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18
Q

How do organisms become specialized for their prime niches?

A
  • Evolutionary pressures of selection

- Competition

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19
Q

Why can’t two populations of organisms occupy the same niche?

A

One population will always outcompete

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20
Q

What do we call environments in which conditions change over short distances?

A

Microenvironments

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21
Q

What experiment demonstrated the importance of EPS production?

A

EPS production by Escherichia coli K12 during biofilm formation

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22
Q

Which bacterium is use to understand the practical concerns associated with biofilms?

A

Pseudomonas aeruginosa

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23
Q

What human disease are characterized by biofilm formation?

A

Cystic Fibrosis

24
Q

What is the unit that estimates the number of bacterial or fungal cells in a sample which are viable, able to multiply?

A

Colony-forming unit

25
Q

Using molecular techniques such as sequencing and analysis of nucleic acids extracted from environmental samples is known as what?

A

Cultivation-Independent Techniques

26
Q

What are some examples of Indirect method for characterizing microbial ecosystems?

A
  • Denaturing gradient gel electrophoresis
  • Terminal restriction fragment length polymorphism (T-RFLP)
  • Stable Isotope Probing
  • Fluorescence-activated cell sorting (FACS)
27
Q

Method used to separate small PCR-amplified DNA fragments of 200-700 base pairs that have been obtained from an environmental sample

A

Denaturing gradient gel electrophoresis

28
Q

Technique in which microbial communities are examined by the position of a restriction site closest to a labeled end of an amplified gene

A

Terminal restriction fragment length polymorphism (T-RFLP)

29
Q

Technique in which fluorescence can be used to screen cells

A

Fluorescence-activated cell sorting (FACS)

30
Q

Technique in which microorganisms are examined to see if they are capable of metabolizing a given compound by using stable isotopes

A

Stable-isotope probing

31
Q

What made it possible to learn an enormous amount about the types of microorganisms present in the environment and their relationship to one another

A

SSU rRNA

32
Q

What is a tool that involves the construction of gene libraries from DNA extracted directly from the environment?

A

Metagenomics

33
Q

What are the three major zones of the ocean?

A
  • Surface Zone
  • Dark Mid-water Zone
  • Deep Sea Zone
34
Q

What zone is caused by the scarcity of key nutrients like nitrogen and phosphorus that limits photosynthesis?

A

Dead Zones

35
Q

What kind of organisms can reside at the depths of the Deep Sea Zone?

A
  • Microorganisms that can withstand extremely high atmospheric pressures
  • Piezophiles or barophiles
36
Q

What zone experiences agricultural activities such as runoff?

A

Dead Zones

37
Q

What zone does photosynthetic microbes inhabit?

A

Surface Zone

38
Q

Which non-photosynthetic microbe graze on primary producers and other microbes in the surface zone?

A

Zooplankton

39
Q

Which zone does photosynthesis not occur and microbial life is fed by the organic matter produced in the upper surface waters?

A

Dark Mid-water Zone

40
Q

Which zone exhibits extremely high atmospheric pressures?

A

Deep Sea Zones

41
Q

What happens to the plasma fluidity and enzyme function in the Deep Sea Zone?

A

Decreases

42
Q

What role does viruses play in the oceans?

A
  • Control the microbial communities that exist within the marine water column
  • Cyanobacteria lyse and fragments of plasma membrane, DNA, proteins, and nutrients are released into the environment
43
Q

What is the term called when seawater samples are diluted so that very few cells remain in each aliquot?

A

Dilution to extinction

44
Q

What is the thin band over the terrestrial surface of Earth that contains more microbial diversity and activity than any other microbial system called?

A

Soil

45
Q

What distinguishes biomes?

A

Temperature and precipitation

46
Q

What factors are influenced by biomes?

A
  • Latitude
  • Elevation
  • Geological features
47
Q

What biome plays a central role in the dominant primary producers, providing nutrients to the soil via microbial decomposition and photosynthesis- derived root exudates?

A

Terrestrial biomes

48
Q

Which horizon contains inorganic matter, and closest to bedrock?

A

C Horizon

49
Q

Which horizon contains subsoil and some organic matter?

A

B Horizon

50
Q

Which horizon contains topsoil?

A

A Horizon

51
Q

Which horizon composes the organic matter on the surface of the soil?

A

O Horizon

52
Q

What is the result from incomplete breakdown of plant biomass called?

A

Humic material

53
Q

Which part of the soil immediately surrounds the plant roots, and represent a distinct and important ecosystem?

A

Rhizosphere

54
Q

Which contains higher numbers of microbes, bulk soil or rhizosphere?

A

Rhizosphere

55
Q

What are chemicals that are not naturally found or produced by organisms and are detrimental to human and animal health called?

A

Xenobiotics