Microbial Metabolism Many microorganisms have some of the same metabolic pathways as humans Two types of metabolism ALL REACTIONS REQUIRE ENZYMES Anabolism building synthesis reactions ex protein synthesis Catabolism degradation breaking down reactions Microbial Metabolism Energy production metabolism Catabolic End result is ATP energy currency of cell Chemoheterotrophs humans many microbes Cellular respiration aerobic respiration Glucose Krebs Cycle TCA or Citric acid cycle Electron Transport Chain Microbes have other types of metabolism other than cellular respiration ATP Picture contains phosphate sugar nitrogenous base Overview Picture different pathways use ATP to create different types of work Chemical work Transport work transporting chemicals across membranes Mechanical work movement of cell parts Energy Metabolism of Microorganisms Cellular Respiration Anaerobic Respiration Fermentation Chemolithotrophy Photosynthesis ATP Production Metabolic Pathways for ATP Production 1 Chemoheterotrophy Cellular respiration fermentaion anaerobic respiration Oxidant of organic compounds electron donor Example donor glucose 2 Chemolithotrophy chemoautotrophy Oxidation of inorganic compounds electron donor Example donor nitrite 3 Phototrophy photoautotrophy Photosynthesis Photons used to boost electrons to higher energy levels which then are transferred to lower levels to produce ATP Example donor water others Cellular Respiration Aerobic Respiration Picture ALL organisms start with an organic molecule ex carbohydrates Monosaccharides are the preferred source ex glucose Electrons contain energy which is put into ATP molecule Low energy end products water carbon dioxide Cellular Respiration Picture 90 of all microorganisms Glycolysis glucose molecule split into two cell makes 2 ATP 2 pyruvic acids 2 NADH usually 12 14 chemical reactions occur NEEDS NAD Krebs Cycle circular cycle starting molecule is pyruvic acid produces 2 ATP gives off 4 CO2 2 FADH2 8 NADH Electron Transport Chain temporary energy starting molecules are FADH2 and NADH slowly extracting energy in electrons oxidation reduction reactions transports electron 34 ATP 6 H2O oxygen nal electron acceptor is used to created H20 Anaerobic Respiration Picture ONLY some types of prokaryotic cells Same as cellular respiration except NO oxygen used in the last step of ETC Used other inorganic compounds Nitrate NO3 reducing bacteria Sulfate SO4 Others Fermentation Anaerobic no oxygen required Partial catabolism breakdown of carbohydrates Energy yield much smaller than cellular respiration Glycolysis present ATP is being produced NO Krebs Cycle or ETC used Organic end products given off Replenishment of NAD Needed to keep glycolysis running Pyruvate converted to other products Acids alcohols gasses ketones aldehydes Results in more NAD End Products of Fermentation Acids many types Alcohols ethanol and butanol common Gasses CO2 and H2 Fermentation Pathways Alcoholic Acidic Fungi Saccharomyces baking brewing yeast ethanol Some bacteria Clostridium propanol butanol Many bacteria Homo fermenters produced 1 acid mixed acid fermenters produces multiple Leavening Uses of Fermentation Food Products Bread Alcohol Beer wine Fermented milk products Fermented vegetables Fermented meats Industry Production of alcohols Yogurt Chemolithotrophy Chemoautotrophy Found in soils and water Only prokaryotes capable of this metabolism Inorganic molecules oxidized Electrons from oxidation used in ETC ATP produced O2 as nal electron acceptor aerobic process Not as energy ef cient as cellular respiration Most are autotrophic gets carbon from CO2 Nitrogen ammonia nitrite Sulfur sulfur sul des thiosulfate Iron ferrous iron ferric iron Hydrogen Importance of Chemolithotrophy Nitri cation N2 Ammonia Nitrate Vital step in many nutrient cycles Nitrogen processing very important Provides usable forms of nitrogen to higher organisms plants
View Full Document
Unlocking...