Microbiology an Introduction Twelfth Edition Chapter 5 PDF

Microbiology an Introduction Twelfth Edition Chapter 5 Microbial Metabolism Copyright © 2016 Pearson Education, Inc. All Rights Reserved Oxidation-Reduction Reactions (1 of 3) Oxidation: removal of electrons Red...

Microbiology an Introduction Twelfth Edition Chapter 5 Microbial Metabolism Copyright © 2016 Pearson Education, Inc. All Rights Reserved Oxidation-Reduction Reactions (1 of 3) Oxidation: removal of electrons Reduction: gain of electrons Redox reaction: an oxidation reaction paired with a reduction reaction Copyright © 2016 Pearson Education, Inc. All Rights Reserved Oxidation-Reduction Reactions (3 of 3) In biological systems, electrons and protons are removed at the same time; equivalent to a hydrogen atom Biological oxidations are often dehydrogenations Copyright © 2016 Pearson Education, Inc. All Rights Reserved Metabolic Pathways of Energy Production Series of enzymatically catalyzed chemical reactions Extracts energy from organic compounds and stores it in chemical form (ATP) Copyright © 2016 Pearson Education, Inc. All Rights Reserved Carbohydrate Catabolism (2 of 2) The breakdown of carbohydrates to release energy – Glycolysis – Krebs cycle – Electron transport chain (system) Copyright © 2016 Pearson Education, Inc. All Rights Reserved Glycolysis (1 of 4) The oxidation of glucose to pyruvic acid produces ATP and NADH Copyright © 2016 Pearson Education, Inc. All Rights Reserved Cellular Respiration Oxidation of molecules liberates electrons to operate an electron transport chain Final electron acceptor comes from outside the cell and is inorganic ATP is generated by oxidative phosphorylation Copyright © 2016 Pearson Education, Inc. All Rights Reserved Aerobic Respiration (1 of 5) Krebs cycle – Pyruvic acid (from glycolysis) is oxidized and decarboxylation (loss of CO2) occurs – The resulting two-carbon compound attaches to coenzyme A, forming acetyl CoA and NADH Copyright © 2016 Pearson Education, Inc. All Rights Reserved Aerobic Respiration (2 of 5) Krebs cycle – Oxidation of acetyl CoA produces NADH, FADH2, and ATP, and liberates CO2 as waste Copyright © 2016 Pearson Education, Inc. All Rights Reserved Carbohydrate Catabolism Each NADH can be oxidized in the electron transport chain to produce 3 molecules of ATP Each FADH2 can produce 2 molecules of ATP Copyright © 2016 Pearson Education, Inc. All Rights Reserved Anaerobic Respiration (1 of 2) The final electron acceptor in the electron transport chain is NOT O2 – Yields less energy than aerobic respiration Copyright © 2016 Pearson Education, Inc. All Rights Reserved Anaerobic Respiration (2 of 2) Copyright © 2016 Pearson Education, Inc. All Rights Reserved Table 5.3 ATP Yield During Prokaryotic Aerobic Respiration of One Glucose Molecule TABLE 5.3 ATP Yield during Prokaryotic Aerobic Respiration of One Glucose Molecule Copyright © 2016 Pearson Education, Inc. All Rights Reserved Fermentation (1 of 3) Releases energy from the oxidation of organic molecules Does not require oxygen Does not use the Krebs cycle or ETC Uses an organic molecule as the final electron acceptor Produces only small amounts of ATP Copyright © 2016 Pearson Education, Inc. All Rights Reserved Figure 5.18a Fermentation Copyright © 2016 Pearson Education, Inc. All Rights Reserved Fermentation (2 of 3) Lactic acid fermentation: produces lactic acid – Homolactic fermentation: produces lactic acid only – Heterolactic fermentation: produces lactic acid and other compounds Glucose is oxidized to pyruvic acid, which is then reduced by NADH Copyright © 2016 Pearson Education, Inc. All Rights Reserved Fermentation (3 of 3) Alcohol fermentation: produces ethanol + CO2 Glucose is oxidized to pyruvic acid; pyruvic acid is converted to acetaldehyde and CO2; NADH reduces acetaldehyde to ethanol Copyright © 2016 Pearson Education, Inc. All Rights Reserved Figure 5.19 Types of Fermentation Copyright © 2016 Pearson Education, Inc. All Rights Reserved Figure 5.18b Fermentation Copyright © 2016 Pearson Education, Inc. All Rights Reserved Table 5.4 Some Industrial Uses for Different Types of Fermentations* (1 of 2) TABLE 5.4 Some Industrial Uses for Different Types of Fermentations* Fermentation End- Industrial or Starting Material Microorganism Product(s) Commercial Use Ethanol Beer, wine Starch, sugar Saccharomyces cerevisiae (yeast, a fungus) Blank Fuel Agricultural wastes Saccharomyces cerevisiae (yeast) Acetic Acid Vinegar Ethanol Acetobacter Lactic Acid Cheese, yogurt Milk Lactobacillus, Streptococcus Blank Rye bread Grain, sugar Lactobacillus delbrueckii Blank Sauerkraut Cabbage Lactobacillus plantarum Blank Summer sausage Meat Pediococcus Copyright © 2016 Pearson Education, Inc. All Rights Reserved Table 5.4 Some Industrial Uses for Different Types of Fermentations* (2 of 2) Fermentation End- Industrial or Starting Material Microorganism Product(s) Commercial Use Propionic Acid and Swiss cheese Lactic acid Propionibacterium Carbon Dioxide freudenreichii Acetone and Butanol Pharmaceutical, Molasses Clostridium industrial uses acetobutylicum Citric Acid Flavoring Molasses Aspergillus (fungus) Methane Fuel Acetic acid Methanosarcina (archaeon) Sorbose Vitamin C (ascorbic Sorbitol Gluconobacter acid) *Unless otherwise noted, the microorganisms listed are bacteria. Copyright © 2016 Pearson Education, Inc. All Rights Reserved Figure 5.11 An Overview of Respiration and Fermentation (2 of 2) Copyright © 2016 Pearson Education, Inc. All Rights Reserved Lipid and Protein Catabolism (2 of 2) Extracellular proteases Protein        Amino acids Deamination, decarboxylation, dehydrogenation, desulfurization           Organic acid Krebs cycle Copyright © 2016 Pearson Education, Inc. All Rights Reserved Figure 5.20 Lipid Catabolism Copyright © 2016 Pearson Education, Inc. All Rights Reserved Figure 5.21 Catabolism of Various Organic Food Molecules Copyright © 2016 Pearson Education, Inc. All Rights Reserved Biochemical Tests and Bacterial Identification (3 of 3) Fermentation test: bacteria that catabolize carbohydrate or protein produce acid, causing the pH indicator to change color Oxidase test: identifies bacteria that have cytochrome oxidase (e.g., Pseudomonas) Copyright © 2016 Pearson Education, Inc. All Rights Reserved Photosynthesis (2 of 3) Light-dependent (light) reactions: conversion of light energy into chemical energy (ATP and NADPH) Light-independent (dark) reactions: ATP and NADPH are used to reduce CO2 to sugar (carbon fixation) via the Calvin-Benson cycle Copyright © 2016 Pearson Education, Inc. All Rights Reserved Photosynthesis (3 of 3) Oxygenic: 6 CO2 + 12 H2 O + Light energy C6 H12 O6 + 6 H2 O + 6 O2 Anoxygenic: 6 CO2 + 12 H2S + Light energy C6H12O 6 + 6 H2O + 12 S Copyright © 2016 Pearson Education, Inc. All Rights Reserved Figure 5.25a Photophosphorylation Copyright © 2016 Pearson Education, Inc. All Rights Reserved Figure 5.25b Photophosphorylation Copyright © 2016 Pearson Education, Inc. All Rights Reserved Metabolic Diversity Among Organisms (2 of 4) Phototrophs use light energy Photoautotrophs use energy in the Calvin-Benson cycle to fix CO2 to sugar – Oxygenic: produces O2 – Anoxygenic: does not produce O2 Copyright © 2016 Pearson Education, Inc. All Rights Reserved Table 5.6 Photosynthesis Compared in Selected Eukaryotes and Prokaryotes TABLE 5.6 Photosynthesis Compared in Selected Eukaryotes and Prokaryotes Prokaryotes Prokaryotes Prokaryotes Characteristic Eukaryotes Cyanobacteria Green Bacteria Purple Bacteria Substance That H atoms of H atoms of H2O Sulfur, sulfur Sulfur, sulfur Reduces CO2 H2O compounds, H2 gas compounds, H2 gas Oxygen Oxygenic Oxygenic (and Anoxygenic Anoxygenic Production anoxygenic) Type of Chlorophyll a Chlorophyll a Bacteriochlorophyll a Bacteriochlorophyll Chlorophyll a or b Site of Chloroplasts Thylakoids Chlorosomes Chromatophores Photosynthesis with thylakoids Environment Aerobic Aerobic (and Anaerobic Anaerobic anaerobic) Copyright © 2016 Pearson Education, Inc. All Rights Reserved Metabolic Diversity Among Organisms (4 of 4) Nutritional Type Energy Source Carbon Source Example Photoautotroph Light CO2 Oxygenic: Cyanobacteria, plants Anoxygenic: Green bacteria, purple bacteria Photoheterotroph Light Organic compounds Green bacteria, purple nonsulfur bacteria Chemoautotroph Inorganic CO2 Iron-oxidizing bacteria Chemical Chemoheterotroph Chemical Organic compounds Fermentative bacteria Animals, protozoa, fungi, bacteria Copyright © 2016 Pearson Education, Inc. All Rights Reserved