Module 4 - Microbial Ecosystems

Question 1

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

Answer 1

Niche

Question 2

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

Answer 2

• Type
• Quality
• Quantity

Question 3

What is the general rule in ecology?

Answer 3

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

Question 4

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

Answer 4

Methanobrevibacter smithii and E.coli

Question 5

E.coli is the … in the colon

Answer 5

Fermenter

Question 6

M. smithii is a … in the colon

Answer 6

Methanogen

Question 7

Structured communities held together by extracellular polysaccharides are called?

Answer 7

Biofilms

Question 8

How does biofilm growth provide an advantage for microorganisms?

Answer 8

Nutrients bind to solid surfaces; enables higher cell concentrations

Question 9

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

Answer 9

• Appendaged bacteria

- Caulobacter or Hyphomicrobium

Question 10

Species that divide and form microcolonies are called?

Answer 10

Primary colonizers

Question 11

Species that join the growing biofilms are called?

Answer 11

Secondary colonizers

Question 12

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

Answer 12

Exopolyssacharides (EPS)

Question 13

What are the functions of the gel-like matrix?

Answer 13

• Aids in the formation of water-filled channels

- Facilitates the transport of nutrients and waste through the biofilm

Question 14

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

Answer 14

Cultivation-Dependent Techniques

Question 15

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

Answer 15

Azotobacter

Question 16

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

Answer 16

Cultivation-Independent Techniques

Question 17

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

Answer 17

Abiotic factors

Question 18

How do organisms become specialized for their prime niches?

Answer 18

• Evolutionary pressures of selection

- Competition

Question 19

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

Answer 19

One population will always outcompete

Question 20

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

Answer 20

Microenvironments

Question 21

What experiment demonstrated the importance of EPS production?

Answer 21

EPS production by Escherichia coli K12 during biofilm formation

Question 22

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

Answer 22

Pseudomonas aeruginosa

Question 23

What human disease are characterized by biofilm formation?

Answer 23

Cystic Fibrosis

Question 24

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

Answer 24

Colony-forming unit

Question 25

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

Answer 25

Cultivation-Independent Techniques

Question 26

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

Answer 26

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

Question 27

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

Answer 27

Denaturing gradient gel electrophoresis

Question 28

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

Answer 28

Terminal restriction fragment length polymorphism (T-RFLP)

Question 29

Technique in which fluorescence can be used to screen cells

Answer 29

Fluorescence-activated cell sorting (FACS)

Question 30

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

Answer 30

Stable-isotope probing

Question 31

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

Answer 31

SSU rRNA

Question 32

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

Answer 32

Metagenomics

Question 33

What are the three major zones of the ocean?

Answer 33

- Surface Zone - Dark Mid-water Zone - Deep Sea Zone

Question 34

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

Answer 34

Dead Zones

Question 35

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

Answer 35

- Microorganisms that can withstand extremely high atmospheric pressures - Piezophiles or barophiles

Question 36

What zone experiences agricultural activities such as runoff?

Answer 36

Dead Zones

Question 37

What zone does photosynthetic microbes inhabit?

Answer 37

Surface Zone

Question 38

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

Answer 38

Zooplankton

Question 39

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

Answer 39

Dark Mid-water Zone

Question 40

Which zone exhibits extremely high atmospheric pressures?

Answer 40

Deep Sea Zones

Question 41

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

Answer 41

Decreases

Question 42

What role does viruses play in the oceans?

Answer 42

- 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

Question 43

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

Answer 43

Dilution to extinction

Question 44

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

Answer 44

Soil

Question 45

What distinguishes biomes?

Answer 45

Temperature and precipitation

Question 46

What factors are influenced by biomes?

Answer 46

- Latitude - Elevation - Geological features

Question 47

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

Answer 47

Terrestrial biomes

Question 48

Which horizon contains inorganic matter, and closest to bedrock?

Answer 48

C Horizon

Question 49

Which horizon contains subsoil and some organic matter?

Answer 49

B Horizon

Question 50

Which horizon contains topsoil?

Answer 50

A Horizon

Question 51

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

Answer 51

O Horizon

Question 52

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

Answer 52

Humic material

Question 53

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

Answer 53

Rhizosphere

Question 54

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

Answer 54

Rhizosphere

Question 55

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

Answer 55

Xenobiotics