Microbiology An Introduction Chapter 5 PDF

Microbiology an Introduction Thirteenth Edition Chapter 5 Microbial Metabolism Copyright © 2019 Pearson Education, Inc. All Rights Reserved Dental Plaque Consists of Bacteria Copyright © 2019 Pearson Education, Inc. All Rights Reserved Big Picture: Metabolism (1 of 4) Metabolism is the buildup and b...

Microbiology an Introduction Thirteenth Edition Chapter 5 Microbial Metabolism Copyright © 2019 Pearson Education, Inc. All Rights Reserved Dental Plaque Consists of Bacteria Copyright © 2019 Pearson Education, Inc. All Rights Reserved Big Picture: Metabolism (1 of 4) Metabolism is the buildup and breakdown of nutrients within a cell These chemical reactions provide energy and create substances that sustain life Copyright © 2019 Pearson Education, Inc. All Rights Reserved Big Picture: Metabolism (2 of 4) For Long description, see slide 150: Appendix 1 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Big Picture: Metabolism (3 of 4) Although microbial metabolism can cause disease and food spoilage, many pathways are beneficial rather than pathogenic Copyright © 2019 Pearson Education, Inc. All Rights Reserved Big Picture: Metabolism (4 of 4) Copyright © 2019 Pearson Education, Inc. All Rights Reserved Catabolic and Anabolic Reactions (1 of 3) Learning Objectives 5-1 Define metabolism, and describe the fundamental differences between anabolism and catabolism. 5-2 Identify the role of ATP as an intermediate between catabolism and anabolism Copyright © 2019 Pearson Education, Inc. All Rights Reserved Catabolic and Anabolic Reactions (2 of 3) Catabolism: breaks down complex molecules; provides energy and building blocks for anabolism; exergonic Anabolism: uses energy and building blocks to build complex molecules; endergonic Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-1 The Role of ATP in Coupling Anabolic and Catabolic Reactions For Long description, see slide 151: Appendix 2 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Catabolic and Anabolic Reactions (3 of 3) Metabolic pathways are sequences of enzymatically catalyzed chemical reactions in a cell Metabolic pathways are determined by enzymes Enzymes are encoded by genes Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-1 Check Your Understanding 5-1 Distinguish catabolism from anabolism. 5-2 How is ATP an intermediate between catabolism and anabolism? Copyright © 2019 Pearson Education, Inc. All Rights Reserved Enzymes Learning Objectives 5-3 Identify the components of an enzyme. 5-4 Describe the mechanism of enzymatic action. 5-5 List the factors that influence enzymatic activity. 5-6 Distinguish competitive and noncompetitive inhibition. 5-7 Define ribozyme Copyright © 2019 Pearson Education, Inc. All Rights Reserved Collision Theory The collision theory states that chemical reactions occur when atoms, ions, and molecules collide Activation energy is the collision energy required for a chemical reaction to occur Reaction rate is the frequency of collisions containing enough energy to bring about a reaction – Reaction rate can be increased by enzymes or by increasing temperature, pressure, or concentration Copyright © 2019 Pearson Education, Inc. All Rights Reserved Enzymes and Chemical Reactions (1 of 2) Catalysts speed up chemical reactions without being altered Enzymes are biological catalysts Enzymes act on a specific substrate and lower the activation energy Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-2 Energy Requirements of a Chemical Reaction For Long description, see slide 152: Appendix 3 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Enzymes and Chemical Reactions (2 of 2) Substrate contacts the enzyme’s active site to form an enzyme-substrate complex Substrate is transformed and rearranged into products, which are released from the enzyme Enzyme is unchanged and can react with other substrates Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-3a The Mechanism of Enzymatic Action For Long description, see slide 153: Appendix 4 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Animation: Enzymes: Steps in a Reaction Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-3b The Mechanism of Enzymatic Action For Long description, see slide 154: Appendix 5 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Enzyme Specificity and Efficiency Enzymes have specificity for particular substrates Turnover number is the number of substrate molecules an enzyme converts to a product per second – Generally 1 to 10,000 – Can be as high as 500,000 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Naming Enzymes Names of enzymes usually end in ase; grouped based on the reaction they catalyze Oxidoreductase: oxidation-reduction reactions Transferase: transfer functional groups Hydrolase: hydrolysis Lyase: removal of atoms without hydrolysis Isomerase: rearrangement of atoms Ligase: joining of molecules; uses ATP Copyright © 2019 Pearson Education, Inc. All Rights Reserved Enzyme Components (1 of 2) Apoenzyme: protein portion (inactive when alone) Cofactor: nonprotein component – Coenzyme: organic cofactor Holoenzyme: apoenzyme plus cofactor (whole, active enzyme form) Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-4 Components of a Holoenzyme For Long description, see slide 155: Appendix 6 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Enzyme Components (2 of 2) Assist enzymes; electron carriers – Nicotinamide adenine dinucleotide (NAD+ ) – Nicotinamide adenine dinucleotide phosphate (NADP+ ) – Flavin adenine dinucleotide (FAD) – Coenzyme A Copyright © 2019 Pearson Education, Inc. All Rights Reserved Factors Influencing Enzyme Activity (1 of 2) Temperature pH Substrate concentration Inhibitors Copyright © 2019 Pearson Education, Inc. All Rights Reserved Factors Influencing Enzyme Activity (2 of 2) High temperature and extreme pH denature proteins If the concentration of substrate is high (saturation), the enzyme catalyzes at its maximum rate Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-6 Denaturation of a Protein For Long description, see slide 156: Appendix 7 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-5a Factors That Influence Enzymatic Activity, Plotted for a Hypothetical Enzyme For Long description, see slide 157: Appendix 8 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-5b Factors That Influence Enzymatic Activity, Plotted for a Hypothetical Enzyme For Long description, see slide 158: Appendix 9 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-5c Factors That Influence Enzymatic Activity, Plotted for a Hypothetical Enzyme For Long description, see slide 159: Appendix 10 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Inhibitors (1 of 2) Competitive inhibitors fill the active site of an enzyme and compete with the substrate Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-7a-b Enzyme Inhibitors For Long description, see slide 160: Appendix 11 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Sulfanilamide V s PABA Figure, Pg. 116 ersu a e For Long description, see slide 161: Appendix 12 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Inhibitors (2 of 2) Noncompetitive inhibitors interact with another part of the enzyme (allosteric site) rather than the active site in a process called allosteric inhibition – This indirectly changes the shape of the active site, rendering the enzyme nonfunctional – Can be reversible or irreversible Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-7a-c Enzyme Inhibitors For Long description, see slide 162: Appendix 13 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Feedback Inhibition End-product of a reaction allosterically inhibits enzymes from earlier in the pathway Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-8 Feedback Inhibition For Long description, see slide 163: Appendix 14 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Ribozymes RNA that function as catalysts by binding to substrates and acting upon them – Not used up in the reaction – Frequently used in cells to cut and splice RNA – Also involved in protein synthesis in ribosomes Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-2 Check Your Understanding 5-3 What is a coenzyme? 5-4 Why is enzyme specificity important? 5-5 What happens to an enzyme below its optimal temperature? Above its optimal temperature? 5-6 Why is feedback inhibition noncompetitive inhibition? 5-7 What is a ribozyme? Copyright © 2019 Pearson Education, Inc. All Rights Reserved Energy Production Learning Objectives 5-8 Explain the term oxidation-reduction. 5-9 List and provide examples of three types of phosphorylation reactions that generate ATP. 5-10 Explain the overall function of metabolic pathways Copyright © 2019 Pearson Education, Inc. All Rights Reserved Oxidation-Reduction Reactions (1 of 2) Oxidation: removal of electrons Reduction: gain of electrons Redox reaction: an oxidation reaction paired with a reduction reaction Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-9 Oxidation-Reduction For Long description, see slide 164: Appendix 15 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Animation: Oxidation-Reduction Reactions Copyright © 2019 Pearson Education, Inc. All Rights Reserved Oxidation-Reduction Reactions (2 of 2) In biological systems, electrons and protons are removed at the same time; equivalent to a hydrogen atom Biological oxidations are often dehydrogenations Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-10 Representative Biological Oxidation For Long description, see slide 165: Appendix 16 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-3 Check Your Understanding 5-8 Why is glucose such an important molecule for organisms? Copyright © 2019 Pearson Education, Inc. All Rights Reserved The Generation of ATP ATP is generated by the phosphorylation of ADP with the input of energy Copyright © 2019 Pearson Education, Inc. All Rights Reserved Conversion of ADP to ATP Figure, Pg. 118 a e Copyright © 2019 Pearson Education, Inc. All Rights Reserved Substrate-Level Phosphorylation ATP is generated when high-energy PO4 is added to ADP Copyright © 2019 Pearson Education, Inc. All Rights Reserved Addition of Phosphate to ADP to Form ATP Figure, Pg. 118 a e Copyright © 2019 Pearson Education, Inc. All Rights Reserved Oxidative Phosphorylation Electrons are transferred from one electron carrier to another along an electron transport chain (system) on a membrane that releases energy to generate ATP – Chemiosmosis is the term for the process wherein ATP is generated from ADP using the energy derived from the electron transport chain Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-14 An Electron Transport Chain (System) (1 of 2) For Long description, see slide 166: Appendix 17 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Photophosphorylation Occurs only in photosynthetic cells with light-trapping pigments such as chlorophylls Light energy is converted to chemical energy in the form of ATP during the transfer of electrons (oxidation) from chlorophyll as they pass through a system of carrier molecules Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-25 Photophosphorylation For Long description, see slide 167: Appendix 18 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-4 Check Your Understanding 5-9 Outline the three ways that ATP is generated. Copyright © 2019 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 © 2019 Pearson Education, Inc. All Rights Reserved Hypothetical Metabolic Pathway Figure, Pg. 119 a e For Long description, see slide 168: Appendix 19 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-5 Check Your Understanding 5-10 What is the purpose of metabolic pathways? Copyright © 2019 Pearson Education, Inc. All Rights Reserved Carbohydrate Catabolism (1 of 3) Learning Objectives 5-11 Describe the chemical reactions of glycolysis. 5-12 Identify the functions of the pentose phosphate and EntnerDoudoroff pathways. 5-13 Explain the products of the Krebs cycle. 5-14 Describe the chemiosmotic model for ATP generation. 5-15 Compare and contrast aerobic and anaerobic respiration. 5-16 Describe the chemical reactions of, and list some products of, fermentation Copyright © 2019 Pearson Education, Inc. All Rights Reserved Carbohydrate Catabolism (2 of 3) The breakdown of carbohydrates to release energy typically occurs in three principle stages – Glycolysis – Krebs cycle – Electron transport chain (system) Copyright © 2019 Pearson Education, Inc. All Rights Reserved Foundation Figure 5-11 an Overview of Respiration and Fermentation (1 of 2) For Long description, see slide 169: Appendix 20 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Glycolysis (1 of 4) The oxidation of glucose to pyruvic acid produces ATP and NADH Copyright © 2019 Pearson Education, Inc. All Rights Reserved Glycolysis (2 of 4) Preparatory stage – 2 ATP are used – Glucose is split to form two molecules: one glyceraldehyde 3-phosphate (g P), and one dihydroxyacetone phosphate (DHAP) – DHAP is readily converted to g P ram ram Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-12 An Outline of the Reactions of Glycolysis (Embden-Meyerhof Pathway) For Long description, see slide 170: Appendix 21 (1 of 2) Copyright © 2019 Pearson Education, Inc. All Rights Reserved Glycolysis (3 of 4) Energy-conserving stage – The two glyceraldehyde 3-phosphate molecules are oxidized to 2 pyruvic acid molecules – 4 ATP are produced – 2 NADH are produced Copyright © 2019 Pearson Education, Inc. All Rights Reserved Glycolysis (4 of 4) Glucose + 2 ATP + 2 ADP 2 PO 4 - + 2NAD + ® 2 Pyruvic acid + 4ATP + 2NADH + 2H + Overall net gain of two molecules of ATP for each molecule of glucose oxidized Copyright © 2019 Pearson Education, Inc. All Rights Reserved Additional Pathways to Glycolysis Pentose phosphate pathway – Breaks down five-carbon pentose sugars and/or glucose and produces NADPH – Operates simultaneously with glycolysis – Can provide intermediates for synthesis reactions Entner-Doudoroff pathway – Produces NADPH and ATP – Does not involve glycolysis; operates independently – Occurs in Pseudomonas, Rhizobium, and Agrobacterium Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-6 Check Your Understanding 5-11 What happens during the preparatory and energyconserving stages of glycolysis? 5-12 What is the value of the pentose phosphate and Entner-Doudoroff pathways if they produce only one ATP molecule? Copyright © 2019 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 – Aerobic respiration uses oxygen as the final electron acceptor – Anaerobic respiration uses a molecule other than oxygen as the final electron acceptor ATP is generated by oxidative phosphorylation Copyright © 2019 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 © 2019 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 © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-13 The Krebs Cycle For Long description, see slide 172: Appendix 22 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Aerobic Respiration (3 of 5) Electron transport chain (system) – Occurs in the plasma membrane of prokaryotes; inner mitochondrial membrane of eukaryotes – Series of carrier molecules (flavoproteins, cytochromes, and ubiquinones) are oxidized and reduced as electrons are passed down the chain – Energy released is used to produce ATP by chemiosmosis Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-14 An Electron Transport Chain (System) (2 of 2) For Long description, see slide 173: Appendix 23 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Aerobic Respiration (4 of 5) Chemiosmosis – Electrons (from NADH) pass down the electron transport chain while protons are pumped across the membrane ▪ Establishes proton gradient (proton motive force) – Protons in higher concentration on one side of the membrane diffuse through ATP synthase ▪ Releases energy to synthesize ATP Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-15 Chemiosmosis For Long description, see slide 174: Appendix 24 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-16 Electron Transport and the Chemiosmotic Generation of ATP For Long description, see slide 175: Appendix 25 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Aerobic Respiration (5 of 5) The final electron acceptor in the electron transport chain is molecular oxygen (O2 ) Copyright © 2019 Pearson Education, Inc. All Rights Reserved Summary of Aerobic Respiration Overall Reaction Figure, Pg. 128 a e Copyright © 2019 Pearson Education, Inc. All Rights Reserved Carbohydrate Catabolism (3 of 3) 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 © 2019 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 © 2019 Pearson Education, Inc. All Rights Reserved Anaerobic Respiration (2 of 2) Electron Acceptor Products NO3- NO2- ,N2 + H2O SO24- H2S + H2O CO32- CH4 + H2O N O sub 3 super minus S O sub 4 super 2 minus C O sub 3 super 2 minus N O sub 2 super minus, N sub 2 plus H sub 2 O H sub 2 S + H sub 2 O C H sub 4 + H sub 2 O Copyright © 2019 Pearson Education, Inc. All Rights Reserved Table 5-3 ATP Yield during Prokaryotic Aerobic Respiration of One Glucose Molecule For Long description, see slide 176: Appendix 26 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-7 Check Your Understanding 5-13 What are the principal products of the Krebs cycle? 5-14 How do carrier molecules function in the electron transport chain? 5-15 Compare the energy yield (ATP) of aerobic and anaerobic respiration. Copyright © 2019 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 © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-18a Fermentation For Long description, see slide 177: Appendix 27 Copyright © 2019 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 © 2019 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 © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-19 Types of Fermentation For Long description, see slide 178: Appendix 28 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-18b Fermentation For Long description, see slide 179: Appendix 29 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Table 5-4 Some Industrial Uses for Different Types of Fermentations* Fermentation Endproduct(s) Industrial or Commercial Use Starting Material Ethanol Beer, Wine Starch, sugar Blank Fuel Agricultural wastes Saccharomyces cerevisiae (yeast) Blank Vinegar Ethanol Acetobacter Acetic Acid Cheese, yogurt Milk Lactobacillus, Streptococcus Lactic Acid Rye bread Grain, sugar Lactobacillus delbrueckii Blank Sauerkraut Cabbage Lactobacillus plantarum Blank Summer sausage Meat Pediococcus Propionic Acid and Carbon Swiss cheese Dioxide Lactic acid Propionibacterium freudenreichii Acetone and Butanol Pharmaceutical, industrial uses Molasses Clostridium acetobutylicum Citric Acid Flavoring Molasses Aspergillus (fungus) Methane Fuel Acetic acid Methanosarcina (archaeon) Sorbose Vitamin C (ascorbic acid) Sorbitol Gluconobacter Microorganism Saccharomyces cerevisiae (yeast, a fungus) *Unless otherwise noted, the microorganisms listed are bacteria. Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-8 Check Your Understanding 5-16 List four compounds that can be made from pyruvic acid by an organism that uses fermentation. Copyright © 2019 Pearson Education, Inc. All Rights Reserved Foundation Figure 5-11 an Overview of Respiration and Fermentation (2 of 2) For Long description, see slide 180: Appendix 30 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Lipid and Protein Catabolism (1 of 2) Learning Objective 5-17 Describe how lipids and proteins undergo catabolism Copyright © 2019 Pearson Education, Inc. All Rights Reserved Lipid and Protein Catabolism (2 of 2) Proteins are degraded by extracellular proteases and peptidases into amino acids Amino acids cross plasma membranes – Deaminated, decarboxylated, desulfurized to obtain molecules that can enter the Krebs cycle for further processing Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-20 Lipid Catabolism For Long description, see slide 181: Appendix 31 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-21 Catabolism of Various Organic Molecules For Long description, see slide 182: Appendix 32 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-9 Check Your Understanding 5-17 What are the end-products of lipid and protein catabolism? Copyright © 2019 Pearson Education, Inc. All Rights Reserved Biochemical Tests and Bacterial Identification (1 of 3) Learning Objective 5-18 Provide two examples of the use of biochemical tests to identify bacteria in the laboratory Copyright © 2019 Pearson Education, Inc. All Rights Reserved Biochemical Tests and Bacterial Identification (2 of 3) Biochemical tests identify bacteria by detecting enzymes (e.g., those involved in decarboxylation and dehydrogenation) Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-22 Detecting Amino Acid Catabolizing Enzymes in the Lab Copyright © 2019 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 – Can also be used with a Durham tube to detect gas production during fermentation Oxidase test: identifies bacteria that have cytochrome c oxidase (e.g., Pseudomonas) Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-23 A Fermentation Test For Long description, see slide 183: Appendix 33 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-10 Check Your Understanding 5-18 On what biochemical basis are Pseudomonas and Escherichia differentiated? Copyright © 2019 Pearson Education, Inc. All Rights Reserved Photosynthesis (1 of 3) Learning Objectives 5-19 Compare and contrast cyclic and noncyclic photophosphorylation. 5-20 Compare and contrast the light-dependent and lightindependent reactions of photosynthesis. 5-21 Compare and contrast oxidative phosphorylation and photophosphorylation Copyright © 2019 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 © 2019 Pearson Education, Inc. All Rights Reserved Photosynthesis (3 of 3) Oxygenic (plants, algae, cyanobacteria): 6 CO2 + 12 H2O + Light energy ® C6H12O6 + 6 H2O + O2 Anoxygenic (purple sulfur/green sulfur bacteria): 6 CO2 + 12 H2S+ Light energy ® C6H12O6 + 6 H2O + 12S Copyright © 2019 Pearson Education, Inc. All Rights Reserved Animation: Photosynthesis: Comparing Prokaryotes and Eukaryotes Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-25a Photophosphorylation For Long description, see slide 184: Appendix 34 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-25b Photophosphorylation For Long description, see slide 185: Appendix 35 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-26 A Simplified Version of the Calvin-Benson Cycle For Long description, see slide 186: Appendix 36 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-11 Check Your Understanding 5-19 How is photosynthesis important to catabolism? 5-20 What is made during the light-dependent reactions? 5-21 How are oxidative phosphorylation and photophosphorylation similar? Copyright © 2019 Pearson Education, Inc. All Rights Reserved A Summary of Energy Production Learning Objective 5-22 Write a sentence to summarize energy production in cells Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-27 Requirements of ATP Production For Long description, see slide 187: Appendix 37 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-12 Check Your Understanding 5-22 Summarize how oxidation enables organisms to get energy from glucose, sulfur, or sunlight. Copyright © 2019 Pearson Education, Inc. All Rights Reserved Metabolic Diversity Among Organisms (1 of 2) Learning Objective 5-23 Categorize the various nutritional patterns among organisms according to carbon source and mechanisms of carbohydrate catabolism and ATP generation Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-28 A Nutritional Classification of Organisms For Long description, see slide 188: Appendix 38 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Metabolic Diversity Among Organisms (2 of 2) Phototrophs use light energy to drive ATP production Photoautotrophs use energy obtained initially from light in the Calvin-Benson cycle to fix CO2 to sugar – Oxygenic: produces O2 – Anoxygenic: does not produce O2 Photoheterotrophs use organic compounds as sources of carbon; anoxygenic Copyright © 2019 Pearson Education, Inc. All Rights Reserved Table 5.6 Photosynthesis Compared in Selected Eukaryotes and Prokaryotes Characteristic Eukaryotes Algae, Plants Prokaryotes Cyanobacteria Prokaryotes Green Bacteria Prokaryotes Purple Bacteria Substance That Reduces CO2 H atoms of H2O H atoms of H2O Sulfur. Sulfur compounds, H2 gas Sulfur, sulfur compounds. H2 gas Oxygen production Oxygenic Oxygenic (and an oxygenic) Anoxygenic Anoxygenic Type Of Chlorophyll Chlorophyll a Chlorophyll a Bacteriochlorop hyll a Bacteriochlorop hyll a or b Site of Photosynthesis Thylakoids in chloroplasts Thylakoids Chlorosomes Chromatophores Environment Aerobic Aerobic (and anaerobic) Anaerobic Anaerobic H sub 2 O H sub 2 O H sub 2 C O sub 2 H sub 2 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Chemoautotrophs Obtain energy from inorganic chemicals; use CO2 as carbon source Energy is used in the Calvin-Benson cycle to fix CO2 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Chemoheterotrophs Obtain energy AND carbon from organic chemicals Medically and economically important Copyright © 2019 Pearson Education, Inc. All Rights Reserved Metabolic Diversity Among Organisms (3 of 3) Nutritional Type Photoautotroph Energy Source Carbon Source C O sub 2 CO2 Light Example Oxygenic: Cyanobacteria, plants Anoxygenic: Green bacteria, purple bacteria Photoheterotroph Light Organic compounds Chemoautotroph Inorganic Chemical Chemoheterotroph Chemical C O sub 2 Green bacteria, purple nonsulfur bacteria CO2 Iron-oxidizing bacteria Organic compounds Fermentative bacteria Animals, protozoa, fungi, bacteria Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-13 Check Your Understanding 5-23 Almost all medically important microbes belong to which of the four aforementioned groups? Copyright © 2019 Pearson Education, Inc. All Rights Reserved Metabolic Pathways of Energy Use Learning Objective 5-24 Describe the major types of anabolism and their relationship to catabolism Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-29 The Biosynthesis of Polysaccharides For Long description, see slide 189: Appendix 39 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-30 The Biosynthesis of Simple Lipids For Long description, see slide 190: Appendix 40 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-31a The Biosynthesis of Amino Acids For Long description, see slide 191: Appendix 41 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-31b The Biosynthesis of Amino Acids For Long description, see slide 192: Appendix 42 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-32 The Biosynthesis of Purine and Pyrimidine Nucleotides For Long description, see slide 193: Appendix 43 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-14 Check Your Understanding 5-24 Where do amino acids required for protein synthesis come from? Copyright © 2019 Pearson Education, Inc. All Rights Reserved The Integration of Metabolism (1 of 2) Learning Objective 5-25 Define amphibolic pathways Copyright © 2019 Pearson Education, Inc. All Rights Reserved The Integration of Metabolism (2 of 2) Amphibolic pathways: metabolic pathways that function in both anabolism and catabolism Many pathways function simultaneously with common intermediates Copyright © 2019 Pearson Education, Inc. All Rights Reserved Figure 5-33 The Integration of Metabolism For Long description, see slide 194: Appendix 44 Copyright © 2019 Pearson Education, Inc. All Rights Reserved Check Your Understanding-15 Check Your Understanding 5-25 Summarize the integration of metabolic pathways using peptidoglycan synthesis as an example. Copyright © 2019 Pearson Education, Inc. All Rights Reserved Copyright This work is protected by United States copyright laws and is provided solely for the use of instructors in teaching their courses and assessing student learning. Dissemination or sale of any part of this work (including on the World Wide Web) will destroy the integrity of the work and is not permitted. The work and materials from it should never be made available to students except by instructors using the accompanying text in their classes. All recipients of this work are expected to abide by these restrictions and to honor the intended pedagogical purposes and the needs of other instructors who rely on these materials Copyright © 2019 Pearson Education, Inc. All Rights Reserved