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44 Cards in this Set

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What is environmental microbiology?
-the study of microorganisms as they occur in their natural habitats
What is microbial ecology?
-the study of interrelationships among microorganisms and their environment
What are two aspects to consider in environmental microbiology?
1) levels of microbial associations in the environment
2) role of adaptation in microbial survival
How many bacteria do we know well? Why is this?
-17 phyla
-they're the only ones we could grow in culture
Whatis most interesting about the Archaea group?
-most are extremophiles
What are thre ways biodiversity is held in balance.
1) competition
2) antagonism
3) cooperation
What is competition in biodiversity?
-best adapted microorganisms have adcantageous traits
What is antagonism in biodiversity?
-microbe makes product that actively inhibits the growth of another
What is cooperation in biodiversity?
-microbe's metabolic activities make the environment more favorable for toher microbes which can lead to biofilms
What are biofilms?
-microbial communities
-probably the most predominant form of bacteria
-have a huge impact on infections in humans
List the most common inhabitants of soil from greatest to least.
-bacteria
-fungi
-algae
What are five things that influence the composition of microbes in the soil?
-moisture content
-oxygen
-pH
-temperature
-nutrient availability
What are most soil organisms (because of temperature)?
-mesophiles
What is aquatic microbiology?
-the study of microoganisms living in freshwater and marine environments
What are some types of aquatic environments and what dictates this?
Salt content breaks groups into:
-freshwater systems
-marine systems
-specialized aquatic systems
What salt content is required to make water a marine system?
-3.5%
What are three ways that can cause water pollution?
-physically (oil and organisms)
-chemically
-biologically (E. coli)
What do chemoorganotrophs use for ATP?
Chemolithotrophs (typically live in soil)?
-glycolysis and Krebs cycle
-use inorganics for ATP
What are biogeochemical cycles?
-processes by which organisms cycle nutrients
-elements often converted between oxidized and reduced forms
-organisms convert inorganics into biomass
What are the three processes that biogeochemical cycling entails (also the basis of all cycles)?
1) Production
2) Consumption
3) Decomposition
What happens in biogeochemical cycling during production?
-conversion of inorganic compounds into the organic compounds of biomass
What happens in biogeochemical cycling during consumption?
-organisms eat other organisms, in the process converting organic molecules into other organic molecules
What happens in biogeochemical cycling during decomposition?
-conversion of organic compounds in dead organisms into inorganic compounds
What are some other important biogeochemical cycles?
-carbon
-nitrogen
-sulfur
-phosphorus
-some trace minerals
What is the main point to take away from the simplified carbon cycle?
-too much combustion is occuring; cycle being pulled drastically to the right
Does noncyclic phosphorylation use both PSI and II?
Yes. PS I only is for cyclic since it returns to the beginning
What are prokaryotic phototrophs?
-primary producers of organic molecules
What are the two types of prokaryotic phototrophs?
1) oxygenic
2) anoxygenic
What happens in oxygenic cycles?
-uses H2O as reducing power in electron transport chain and noncyclic photophosphorylation
What happens in anoxygenic cycles?
-uses inorganic molecules as reducing power in electron transport chain and cyclic photophosphorylation (usually found in anoxic environments near source of H2S
What are some bacterial fermentators?
-Clostridium
-Lactobacullus
-Streptococcus
-Ruminococcus
-Peptostreptoccus
-Bacteroides
What is chemolithotrophy?
-obtaining energy from teh oxidation of inorganic molecules; ATP synthesis is the same as cheoorganotrophs but electron donors are different
Why are inorganic electron donors so effective?
-they have very high delta G values and they're abundant in environment (ex; -387 for sulfur)
Who is capable of fixing nitrogen?
-only prokaryotes
What two types of nitrogen fixation can occur?
-free living
-symbiotic
*very expensive! uses nitrogenase
How does the nitrogen cycle work?
-atmospheric nitrogen is fixated into ammonia.
-ammonia and water form ammonium ion
-ammonium ion goes to nitrite (toxic) then nitrate
*main part is immediate converstion to ammonia which is directly usable
Which Gram bacteria have perisplasms?
-only Gram-
*See slide in EM near end for diagram
How does the sulfur cycle work?
-elemental to sulfate (this can go to H2S which isn't useful forming a circle)
-sulfate up to prokaryote proteins, up to animal proteins, up to dead organism proteins
-these proteins go to H2S which gets cycled back across to starting point of environ sulfur
What is the most usable form of sulfur?
How do you get elemental sulfur from sulfide?
-sulfate
-oxidize it
What is important about the phosphorus and trace mineral cycle?
-it doesn't undrego redox reactions
What occurs during the phosphorus cycle?
-phosphorus undergoes little change in oxidation state in environment
-movement from insoluble to soluble forms
-conversion from organic to inorganic forms by pH dependent processes
What is important (or happens) in cycling of trace minerals?
-metal ions are important microbial nutrients
-cycling primarily invovles a transition from an insoluble to a soluble form so they can be used by organisms
What is different (but still acceptable) about Iron in the environment?
-oxidizing Fe will yeild energy, but not much. Organisms will still be able to live there however (just enough)
-need acidic environment
Where is Iron found often (what does it come from)
-pyrite (FeS2) found around coal/metal mines
-when mixed with air, oxidation occurs spontaneously resulting in sulfuric acid (and therefore your acidic environment!).