Microbial Metabolism Metabolism of Energy Production Microbial Metabolism Many microorganisms have some of the same metabolic pathways as humans Two types of metabolism Anabolism building or synthesis reactions Catabolism degradation breaking down reactions Microbial Metabolism Energy production metabolism Catabolic End result is ATP Chemoheterotrophs humans many microbes Cellular respiration aerobic respiration Glycolysis Krebs Cycle TCA or Citric acid cycle Electron transport chain Microbes have other types of metabolism other than cellular respiration ATP Overview Energy Metabolism of Microorganisms Cellular Respiration Anaerobic Respiration Fermentation Chemolithotrophy Photosynthesis ATP Production Cellular Respiration Cellular Respiration Anaerobic Respiration Same as cellular respiration except No oxygen used in last step of ETC Uses other inorganic compounds Nitrate NO3 nitrate reducing bacteria Sulfate SO4 Others Fermentation Anaerobic Partial catabolism of carbohydrates Energy yield much smaller than cellular respiration Glycolysis present Only substrate level phosphorylation No Krebs Cycle or ETC used Organic end products given off Metabolic Pathways for ATP Production Chemoheterotrophy Cellular Respiration Fermentation Anaerobic respiration Oxidation of organic compounds electron donor Example donor glucose Chemolithotrophy chemoautotrophy Oxidation of inorganic compounds electron donor Example donor nitrite Phototrophy photoautotrophy Photons used to boost electrons to higher energy levels which then are transferred to lower levels to produce ATP Acids alcohols gasses ketones aldehydes Replenishment of NAD Needed to keep glycolysis running End Products of Fermentation Acids many types Alcohols Ethanol and butanol common Gasses CO2 and H2 Fermentation Pathways Uses of Fermentation Food Products Bread leavening Alcohol Beer wine Fermented milk products Yogurt Fermented vegetables Fermented meats Production of alcohols Industry Chemolithotrophy Only prokaryotes capable of this metabolism Inorganic molecules oxidized Nitrogen ammonia nitrite Sulfur sulfur sulfides thiosulfate Iron ferrous iron Fe2 ferric iron Fe3 Hydrogen Electrons from oxidation used in ETC ATP produced O2 as final e acceptor Not as energy efficient as cellular respiration Most are autotrophs Importance of Chemolithotrophy Vital step in many nutrient cycles Nitrogen processing very important End Go to Microbial Genetics provides usable forms of nitrogen to higher organisms like plants
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