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Microbial Metabolism

Microbial Metabolism. Biochemical diversity. Metabolism Relationships. Metabolism Pathways. Metabolism. Define Requirements Energy Enzymes Rate Limiting step Reaction time Types Anabolic Endergonic Dehydration Biosynthetic Catabolic Exergonic Hydrolytic Degradative

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Microbial Metabolism

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  1. Microbial Metabolism Biochemical diversity

  2. Metabolism Relationships

  3. Metabolism Pathways

  4. Metabolism • Define • Requirements • Energy • Enzymes • Rate • Limiting step • Reaction time • Types • Anabolic • Endergonic • Dehydration • Biosynthetic • Catabolic • Exergonic • Hydrolytic • Degradative • +/- metabolites

  5. Metabolic Diversity • Energy generating metabolism • Fermentation • Alcohol • Acid Formation • Lactic Acid • Mixed Acids • Others • Respiration • Aerobic • Anaerobic • Biosynthesis of secondary metabolites • Heterotrophic • Autotrophic

  6. Energy • Forms • Kinetic • Potential • Use • Chemical • Mechanical • Electrical • Radiation [EM] • Chemical Types • ATP • UTP • GTP • Heat • Byproduct • 45%

  7. Various Types of Prokaryotic Energy Production Processes • Fermentation • Anaerobic Respiration • Aerobic Respiration • Lithotrophy • Photoheterotrophy • Anoxygenic photosynthesis • Methanogenesis

  8. Enzymes • Structure • Protein • Ribozyme [ribosome] • Characteristic functions • Active site • Specific • Modified Forms • Inactive • Active • Coenzyme/Cofactor • -ase Polymerase Others: Lyases, Hydrolases, Isomerases, Transferases

  9. Enzyme Characteristics

  10. Enzyme Structure • Apoenzyme • Protein • Allosteric site • Cofactor • Metal ions • Cu • Zn • Mg • Fe • Ca • Co • Mn • Coenzyme • Vitamins • CoA • NAD • NADP • FAD • FMN Create Holoenzyme with active site Allosteric site

  11. Factors Affecting Enzymes • Temperature • pH • Acids/Bases • UV light • Concentration of substrates (saturation) • Inhibitors

  12. Enzyme Inhibitors • Classified • Competitive • @ active site • Similar shape • Binding • Irreversible • Reversible • Noncompetitive • @ allosteric site • Change shape • Binding • Irreversible • Reversible

  13. Noncompetitive Enzyme Inhibition

  14. Enzyme Inhibition Summary Noncompetitive at Allosteric site Competitive at active site Excitatory Inhibitory Reversible Irreversible

  15. Glycolysis: Embden-Meyerhoff • Glycolytic • Cytoplasm • Anaerobic • End products • 2 Pyruvic acids • 4-2 = 2 net ATP by substrate level phosphorylation • 2 NADH • 2 H20

  16. Lactic Acid Formation

  17. Glycolysis: PPP • Breakdown 5-6 C • Cytoplasm • Anaerobic • End products • 1 ATP • 2 NADPH • CO2 • 4,5,6,7 C • AA • Nucleotides • Glycolytic pathways • Photosynthesis

  18. Glycolysis: Entner-Duodoroff [E-D] • Glycolytic • Cytoplasm • Anaerobic • Different enzymes • Pseudomonas • Enterococcus • End products • 2-1 = 1 net ATP • NADPH • NADH • 2 Pyruvic acids • H20 NADP+ NADPH

  19. Anaerobic Pathways Compared

  20. Glycolytic Pathways used by various Bacteria

  21. Anaerobic Processes • Lactic Acid • Lactobacillus • Mixed Acid • Enterobacteriaceae • Butanediol • Klebsiella • Enterobacter • Butyric Acid • Clostridia • Butanol-Acetone • Clostridia • Propionic Acid • Corynebacteria

  22. Fermentation

  23. Fermentation Pathways

  24. Fermentation Summary • Anaerobic • Cytoplasm • Partial Oxidation • Small amounts of ATP generated via substrate level phosphorylation • Organic intermediaries as final electron acceptors • End products • Acid: Lactic Acid, Acetic Acid, Butyric Acid, Acetone • Alcohol: Ethanol, Isopropyl • Gas : CO2, H2 • Contaminants

  25. Summary

  26. Carbohydrate Fermentation Tests

  27. Phosphorylation • Substrate Level • Direct transfer of phosphate • Glycolysis • Oxidative Phosphorylation • Electron transfer • Chemiosmosis • Photophosphorylation • Light energy to chemical energy

  28. Substrate Level Phosphorylation

  29. Aerobic Respiration

  30. Mitochondria of Eukaryotes

  31. Plasma [cell] membrane

  32. Acetyl CoA Formation

  33. Acetyl CoA Final Structure

  34. Krebs CycleTCA/Citric Acid Eukaryotic Mitochondria Or Prokaryotic Cytoplasm

  35. Oxidation in Krebs Cycle

  36. Krebs Cycle Metabolites • For every AcetylCoA • 2 CO2 • 3 NADH • 1 FADH2 • 1 ATP (substrate level phosphorylation from GTP) • Regenerates • CoA • Oxaloacetic acid

  37. Dehydrogenation • Use of hydrogen in oxidative reactions • Removal of electron from hydrogen • Carried on vitamin B derivatives • Energy released is trapped in chemical bonds

  38. Redox Reactions

  39. Oxidation

  40. Reduction

  41. Catabolism + Anabolism

  42. Eukaryotic ETC

  43. Prokaryotic ETC Vit B2 Riboflavin based Flavoproteins Metal Proteins with ions (Fe, S, Cu) Iron based Cytochromes (b,c1,c,a,a3) Ubiquiones based on Vit K (CoEnzyme Q)

  44. ETC Steps • Electrons from NADH or FADH2 to flavoproteins (FMN) • H+ pumped into periplasm • Electrons transported • To Iron-Sulfur proteins from NADH • To CoQ from FADH2 • Cytochromes transfer electrons • Final Electron Acceptor • O2 if Aerobic • Other inorganic molecule if Anaerobic

  45. Proton Pump

  46. ETC: NAD NADH + H+

  47. ETC: Cytochromes

  48. Cytochrome Oxidase (Cyt a + Cyt a3)

  49. Oxidase Test Oxidase (+) Pseudomonas Oxidase (-) E.coli, Proteus

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