CH 23 Bacteria

the sum total of all organisms and abiotic factors in a particular environment
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sets of guilds form ____ that interact with macroorganisms and _____ in the ecosystemsmicrobial communities; abiotic factorsWhat is a nichehabitat shared by a guild; supplies nutrients as well as conditions for growthwhat is the study of biologically mediated chemical transformationsbiogeochemistrywhat defines the transformations of a key element by biological or chemical agents? example?biogeochemical cycle; proceed via oxidation-reduction rxnsMicrobes play critical roles in ____ transformations and ______ processes that result in the recycling of elements to living systemsenergy; biogeochemicalwhat two factors does the growth of microbes depend on?resources and growth conditionswhat defines the niche for each microbe?Difference in the type and quantity of resources and the physiochemical conditions of a habitateach organism there exists at least one niche in which that organism is most successful. what is this called?prime nicheWhat is the immediate environmental surroundings of a microbial cell or group of cells called?microenvironmentPhysiochemical conditions in a microenvironment are subject to rapid change, both ___ and ____spatially; temporallyResources in natural environments are highly variable and many microbes in nature face a ______ existencefeast-or-famine_____ and ____ occur between microbes in natural systemscompetition; cooperationwhy are surfaces important in microbial habitats?nutrients adsorb to surfaces; microbial cells can attach to surfacesIdentify biofilmsAssemblages of bacterial cells adhered to a surface and enclosed in an adhesive matrix excreted by the cells; The matrix is typically a mixture of polysaccharides; Biofilms trap nutrients for microbial growth and help prevent detachment of cells in flowing systemsbiofilm formation is initiated by attachment of a ____ to a _____ followed by expression of biofilm-specific genescell; surfacethese biofilm-specific genes encode proteins that synthesize intercellular signaling molecules and initiate _________matrix formationname one biofilm producer. What is critical in the development and maintenance of a biofilm? Name the major intracellular signaling molecules?Pseudomonas aeruginosa ; Intracellular communication; acylated homoserine lactonesWhy do bacteria form biofilms?self-defense; allows cells to remain in a favorable niche; allows bacterial cells to live in close association with one anotherHow do biofilms act as a self-defense?Biofilms resist physical forces that sweep away unattached cells, phagocytosis by immune system cells, and penetration of toxinsName usages of biofilms in today's world and some examples.Medical and dental conditions (periodontal disease, kidney stones, tuberculosis, Legionnaires' disease, and Staphylococcus infections) Industrial settings (biofilms slow the flow of liquids through pipelines and can accelerate corrosion of inert surfaces)Thick biofilms are called what? what are they built by?microbial mats; phototrophic and/or chemolithotropic bacteriaPhototrophic mats contain filamentous______.. Chemolithotrophic mats contain filamentous ________ bacteriacyanobacteria; sulfur-oxidizingWhat is soil? What are soils' two broad groups?the loose outer material of earth's surface. 1) mineral soils derived from rock weathering and other inorganic materials 2) organic soils derived from sedimentation in bogs and marshesSoil is composed of what four things?Inorganic mineral matter (~40% of soil volume) Organic matter (~5%) Air and water (~50%) Living organismsSince most microbial growth takes place on the surfaces of soil particles. ___________ can contain many different microenvironments supporting the growth of several types of microbes.soil aggregatesWhat is the most important factor influencing microbial activity in surface soils? What is the most important factor in subsurface environments?water; nutrientWhat is phylogenetic sampling?Molecular sampling indicates thousands of different microbial species. Note: phylotype: a species defined by a 16S rRNA sequence that differs from all other sequences by 3%Microbial diversity varies with ____ _______ and _________ ________.soil type; geographical locationWhat two organisms are believed to exist in the deep soil subsurface?archaea and bacteriawhy do microorganisms in the deep subsurface have access to nutrients?because groundwater flows through their habitatsFreshwater environments are highly variable in the ________ and conditions available for _____ ______.resources; microbial growthThe balance between _______ and _______ controls the oxygen and carbon cyclesphotosynthesis; respirationIdentify phytoplankton and give examplesoxygenic phototrophs suspended freely in water; algae and cyanobacteriaThe activity of heterotrophic microbes in aquatic systems is highly dependent upon activity of _____ _______primary producersoxygenic phototrophs produce what?organic material and oxygen________ has limited solubility in water; the deep layers of freshwater lakes can become ________ once the _______ is consumed.oxygen; anoxic; oxygenwhat two things is oxygen concentrations in aquatic systems dependent upon?amount of organic matter present and physical mixing of the systemwhat happens to the water column in temperate lakes during the summer?becomes stratifiedRivers can still suffer from oxygen deficiencies due to high inputs in what two things?organic matter from sewage; agricultural and industrial pollutionwhat is the microbial oxygen-consuming capacity of a body of water called?Biochemical Oxygen Demand (BOD)what three factors make the open ocean environment different from freshwater environments?saline; low in nutrients (N, P, Fe); coolerSize of the oceans, the microbial activities taking place in them are major factors in Earth's ______ balance.carbonwhy do near-shore marine waters typically contain higher microbial numbers than the open ocean?Due to higher nutrient levelswhat organism is accounted for in most of the primary productivity in the open ocean due to photosynthesis?prochlorophytesProchlorococcus accounts for:>40% of the biomass of marine phototrophs ~50% of the net primary productionwhere is the planktonic filamentous cyanobacterium Trichodesmium (phototroph) found?tropical and subtropical oceansSmall phototrophic eukaryotes (ostreococcus) inhabit what types of waters where they are important primary producers?coastal and marine watersIdentify Aerobic anoxygenic phototrophsAnother class of marine microbes that use light energy but do not fix carbon dioxide Light is used for ATP synthesis via photophosphorylationSmall planktonic hetertrophic prokaryotes are abundant in ______ marine waterspelagicprokaryote densities in the open ocean ______ with depthdecreaseSurface waters contain about 10^6 cells/ml; cell numbers drop to _________ below 1000 m in depth10^3-10^5/mlwhere do bacterial and archaeal species tend to dominate respectively?surface waters (bacteria); deeper waters (archaea)Oligotroph is an organism that grows best at very ____ nutrient concentrations. Thus the most abundant marine hetertroph is ____ a type of oligotroph.low; pelagibacterPelagibacter and other marine hetertrophs contain ________ a form of rhodopsin. What does this do?proteorhodopsin--allows cells to use light energy to drive ATP synthesisWhat is the most abundant microorganisms in the oceansviruses--at 10^8 virion particles/mlviruses affect ______ populations and are highly diverseprokaryoticHow much of all ocean water is deep sea, lying primarily between 1000 and 6000 m?greater than 75%Organisms that inhabit the deep sea much deal with what four factors?Low Temp.; High pressure; low nutrient levels; absence of light energyDeep-sea microbes are classified as what two types?Psychrophilic (cold-loving) or psychrotolerant Piezophilic (pressure-loving) or piezotoleranthow many proteins allow for adaptations for growth under high pressure?fewWhat are the two types of hydrothermal vents?warm diffuse or very hotwhat bacteria predominate at these vents?chemolithotrophicChemolithotrophic prokaryotes utilize _____ materials from the ventsinorganicWhat assay has detected Bacteria and Archaea in ventsphylogenetic FISHWhat organism dominates hydrothermal ventsproteobacteria