microbial metabolism—procuring energy!

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microbial metabolism glycolysis kreb’s cycle (tca or citric acid cycle oxidative phosphorylation fermentation microbial metabolism— procuring energy! metabolic diversity energy flow for energy for energy carbon flow for anabolism key points dissimulative metabolism—reduction of chemicals for energy—much material must be used to achieve sufficient energy for growth assimilative metabolism—reduction of chemicals for biomass—the cell only uses as much starting material as required anaerobic respiration—molecular oxygen does not serve as an electron acceptor but energy (atp) is produced via chemiosmosis no3-    n2 or so4--  h2s or co2   ch4 1. nitrate    nitrogen gas 2. sulfate  hydrogen sulfide gas 3. carbon dioxide    methane 1,2. standard electron transport, 3. membrane bound enzymes both generate proton gradient required for pmf in anaerobic metabolism nitrate or sulfate serve as terminal electron acceptors at the end of the electron transport chain i ii iii …

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rth as acid rain. sewage treatment plants (water purification): denitrifying bacteria are added to the sewage to convert nitrate to atmospheric nitrogen to remove nitrogen that would otherwise promote the growth of algae significance of denitrification 1. agriculture: soil nitrate that could be fixed to ammonia and assimilated by plants are reduced to atmospheric nitrogen and lost from the soil (however—nitrogen fixing bacteria can restore atmospheric nitrogen to the soil as part of the overall nitrogen cycle) no3-  no2-  no  n2o  n2 nr nr ncor nsor gases to atmosphere significance of denitrification acid rain: atmospheric nitrous oxide is converted to nitric oxide via sunlight. this combined with nitric oxide released via denitrification reacts with ozone to form nitrite that returns to the earth as acid rain. acid rain ozone sunlight h2o no2- nr no3-  no2-  no  n2o  n2 nr nr ncor nsor …

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ount of organic starting material available in the aquatic environment which when metabolized by these bacteria provide the electrons/protons that drive the sulfate to sulfide reaction. disposal of sewage and garbage into waters provides the organic material required for this process sulfides are toxic to living organisms as these sulfides combine with iron centers of cytochromes and hemoglobin thus inhibiting their function n.b. fe can serve as a detoxifying agent as they react with sulfides to produce insoluble fes—black sediments found in aquatic environments are good indicators of pollution!!!) carbon dioxide reduction methanogenesis (methanogens: anaerobic archaebacteria) complex set of reactions that take place in the membranes of these bacteria: protons for co2 reduction come from fermentation, methanogenesis (somewhat different from electron transport) provides proton motive force that drives the production of atp     ch4 glycolysis  pyruvate  fermentation formate, acetate lactate, proprionate butyrate, etc co2 and …

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gs etc. and the hindgut of termites. herbivores: cows/horses/rabbits/termites bacteria degrade cellulose to cellobiose to glucoseglycolysis fermentation  organic acids are assimilated and co2 and h2 are reduced to methane by methanogens omnivores: humans/cats/dogs/pigs vast catabolic processes fermentation methanogenesis of co2 methane waste: cows belch, humans expel gas and i don’t know what the termites do!!! stop here chemolithotrophy—obtaining energy from inorganic chemicals 1. inorganic chemicals are oxidized as coenzymes in the electron transport chain are reduced. 2. oxygen serves as the terminal electron acceptor in electron transport 3. reducing power is not derived from the catabolism of organic matter to produce nadh and fadh therefore these cofactors are usually not re-oxidized in chemolithotropy 4. the chemicals that are oxidized have lower energy potential than nadh, therefore more of these chemicals must be oxidized to generate equivalent proton motive force to produce atp chemolithotrophs tend to grow more slowly than …

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recipitated minerals mixed with seawater/ 270-380oc life in hydrothermal vents bacteria live in the gi tract of tube worms/ the gills of mussels and clams. tube worms/mussels/clams provide co2 as a carbon source for the bacteria. the bacteria oxidize hydrogen sulfide and thiosulfate to h2so4 for energy and reducing power and use this for the assimilation of co2. 4. wastes from bacterial metabolism feed the larger animals there is no sunlight at these depths in the ocean yet niches around the vents are robust with life. chemolithotrophs serve as primary producers significance of sulfur and iron oxidation pollution/acid mine drainage (thiobacillus and metallogenium spp.) strip coal mining exposes the pyrite (fes2) in coal to oxygen. 2. bacteria oxidize ferrous iron to ferric iron 3. oxidation of sulfides to sulfuric acid greatly reduces the ph of the water 4. ferric iron reacts with water to form iron iii hydroxide (fe(oh)3) which …

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О "microbial metabolism—procuring energy!"

microbial metabolism glycolysis kreb’s cycle (tca or citric acid cycle oxidative phosphorylation fermentation microbial metabolism— procuring energy! metabolic diversity energy flow for energy for energy carbon flow for anabolism key points dissimulative metabolism—reduction of chemicals for energy—much material must be used to achieve sufficient energy for growth assimilative metabolism—reduction of chemicals for biomass—the cell only uses as much starting material as required anaerobic respiration—molecular oxygen does not serve as an electron acceptor but energy (atp) is produced via chemiosmosis no3-    n2 or so4--  h2s or co2   ch4 1. nitrate    nitrogen gas 2. sulfate  hydrogen sulfide gas 3. carbon dioxide    methane 1,2. standard electron transport, 3. membrane bound …

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