* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Introductory Microbiology Chap. 5 Chapter Outlines/Notes I
Survey
Document related concepts
Biosynthesis wikipedia , lookup
Metabolic network modelling wikipedia , lookup
Metalloprotein wikipedia , lookup
Citric acid cycle wikipedia , lookup
Adenosine triphosphate wikipedia , lookup
NADH:ubiquinone oxidoreductase (H+-translocating) wikipedia , lookup
Basal metabolic rate wikipedia , lookup
Photosynthesis wikipedia , lookup
Evolution of metal ions in biological systems wikipedia , lookup
Biochemistry wikipedia , lookup
Electron transport chain wikipedia , lookup
Microbial metabolism wikipedia , lookup
Light-dependent reactions wikipedia , lookup
Transcript
Note: While specific end-of-chapter questions are referenced in this document, others may be on the exam. Introductory Microbiology Chap. 5 Chapter Outlines/Notes I. II. III. IV. V. VI. VII. VIII. IX. X. XI. Catabolic and Anabolic Reactions Enzymes Energy Production Carbohydrate Metabolism Lipid and Protein Catabolism Biochemical Tests and Bacterial Identification Photosynthesis A Summary of Energy Production Mechanisms Metabolic Diversity among Organisms Metabolic Pathways of Energy Use The Integration of Metabolism Introduction What basic things do living organisms have to acquire in order to live? What determines what molecules or energy sources a specific species needs or is able to use? All living cells’ energy ‘currency’: Slide 1 Term: Phosphorylation Note: Cells use only two kinds of energy: 1) light energy: trapped and used by plants, algae, and some bacteria for photosynthesis and 2) chemical energy: the energy held in the bonds of various chemicals. Cells do not use thermal or electrical energy because they don't have thermal or electrical converters. Thermal potential (that is, temperature) affects the rate of chemical reactions, but does not provide any energy. What about the electrical signals of nervous impulses? The cells use energy in the form of ATP to generate electric potentials in the membrane of nerve cells and fibers. Those electrical signals are not ‘used’ by the cell to perform other work. 1 Most metabolic processes are ‘similar’ in all cells, but not all. Microbes can do things we cannot do! Crazy things, like eat petroleum or radioactive materials and things that are waste products to us. On the other hand, there are microbes that cannot live in our environment, such as those that are killed by oxygen. I. Catabolic and Anabolic Reactions A. METABOLISM : Two categories of Chemical Processes: Catabolic and Anabolic Reactions Metabolic ‘Pathways’ 2 B. Molecules and Energy- intertwined…. Role of ATP Fig. 2.18 on p. 49 3 II. Enzymes: How they function and what can affect them Enzymes increase the rate of chemical reactions by decreasing the activation energy required for that specific reaction. A. Collision Theory SLIDE 2 B. Enzymes and Chemical Reactions SLIDE 2 Catalysts Substrate(s) Product(s) Decrease activation energy C. Enzyme Specificity and Efficiency Specificity The turnover number is generally 1 to 10,000 molecules per second D. Naming Enzymes See Table 5.1 p. 116 Enzyme Classification Based on Type of Chemical Reaction Catalyzed E. Enzyme Components Slide 3 Fig. 5.3 Apoenzyme (protein portion) Cofactor (nonprotein portion) Haloenzyme F. The Mechanism of Enzymatic Action: The sequence of events in enzyme action on the reactant(s), the enzyme’s substrate(s). Lock and Key Model SLIDE 4 Fig. 5.4 4 G. Factors Influencing Enzyme Activity SLIDE 5, 6 Fig. 5.7 End of Chap. ‘Study Questions’ Review #2 a-c & Critical Thinking #2 1. Example of Competitive Inhibition and its use in Medicine: Sulfa Drugs All cells require folic acid for growth. Folic acid (vitamin B9) in food diffuses or is transported into human cells. However, folic acid cannot cross bacterial cell walls by diffusion or active transport. For this reason bacteria must synthesize folic acid from paminobenzoic acid (PABA). (Find folic acid Table 5.2 p. 117). Folic acid is a vitamin that functions as an enzyme cofactor in the synthesis of nucleotide nitrogen bases. p. 120 Sulfa drugs are chemically similar (chemical analogues) to the chemical PABA. See reactions below for normal functioning (top reaction) and enzyme inhibition when sulfa drugs are used (bottom reaction). When sulfa drugs are present: Since sulfa drugs are chemically similar to (analogues of) PABA, they may “trick” the enzyme into using the sulfa drug to produce folic acid instead of PABA. In effect, the sulfa drug competes with the PABA. When the enzyme is ‘tricked’, the folic acid in the bacterial cell will not produce nitrogen bases. It there is a shortage of nitrogen bases, DNA cannot be replicated, and therefore, growth stops (no binary fission). The bacterial cell has been ‘inhibited’. To date about 15,000 sulfonamide derivatives, analogues, and related compounds have been synthesized. Some disadvantages of sulfa drugs: 1) Only bacteriostatic, not bactericidal 2) Resistance 3) Hypersensitivity 5 4) Crystallization in kidney of patient 2. Noncompetitive Inhibition See Fig. 5.7c p. 120 Allosteric site H. Feedback Inhibition Example: Production of the amino acid isoleucine See Fig. 5.8 p. 121 I. Ribozymes What are they and what chemical reactions do they catalyze? 6 III. Energy Production A. Oxidation-Reduction Reactions Provide energy for… SLIDE 7, 8, 15, 17 End of Chapter ‘Study Questions’ Multiple Choice #1 Removal and Gain of B. The Generation of ATP: Phosphorylation of ADP to ATP Energy is then in… SLIDE 9, 10 1. Substrate-level phosphorylation SLIDE 10, 11, 14, 17 2. Oxidative phosphorylation SLIDE 10, 12, 20 3. Photophosphorylation SLIDE 10, 13 End of Chapter ‘Study Questions’ Review #5 7 C. Metabolic Pathways of Energy Production In the cell, there are many series of enzymatically catalyzed chemical reactions that store energy and release energy from organic molecules- carbohydrates, proteins, and lipids. Catabolic reactions with these molecules release energy for ATP production and anabolic reactions use the energy in those ATPs primarily to synthesize large forms of these molecules. IV. Carbohydrate Metabolism A. Glycolysis SLIDE 14-17 Fig. 5. 11 Foundation Figure: An Overview of Respiration and Fermentation Fig. 5.12 Outline of the reactions of glycolysis Biochemical pathway (10 reactions) in which ONE molecule of GLUCOSE is OXIDIZED to form 2 molecules of PYRUVIC ACID. NAD (nicotinamide adenine dinucleotide, an important electron carrier) is reduced ATP is required in the first stage of glycolysis and formed in the later stage of glycolysis B. Alternatives to Glycolysis Text discussion p. 125, 127 8 After glycolysis… NEXT: Either Cellular Respiration or Fermentation C. Cellular Respiration 1. Aerobic respiration Define respiration: p. 127 a. Glycolysis b. Preparing for the Kreb cycle SLIDE 18 Fig. 5.13 p. 128 c. Krebs cycle SLIDES 19 Fig. 5.13 d. Electron transport chain/ Chemiosmosis/ADP Phosphorylation Electron transport chain: A series of electron carriers are oxidized (lose electrons) & other electron carriers are reduced (gained electrons) as electrons are passed from one electron carrier to another. NADH and FADH2 will donate their electrons to electron carriers located in the prokaryotic plasma membrane. Eukaryotes- occur in the mitochondria. Oxygen is the final electron acceptor in aerobic respiration. Before continuing, turn the page and draw the electron transport chain. Then come back! Info: Some electron carriers pick up one electron, others pick up more than one electron. Some electron carriers carry hydrogen atoms (1e-, 1p+); others ONLY CARRY ELECTRONS (THE PROTON IS SEPARATED FROM THE ELECTRON IN THE H ATOMS). In the electron transport system, FADH2 donates its electrons after NADH. There also is anaerobic respiration (p. 12 this document) where the final electron acceptor is NOT oxygen. Less common & doesn’t produce as much ATP. 9 SLIDE 20 Fig. 5.16 ETC and chemiosmotic generation of ATP Electron Transport Chain 10 Chemiosmosis Fig. 5.15 p. 130, Fig. 5.16 p. 131 1) Occurs simultaneously with the electron transport chain (they are coupled) to transfer the energy to form ATP from ADP and phosphate (ADP phosphorylation). 2) At certain points along the electron transport chain, the hydrogen atom is ‘split’; the electron and the proton are separated. Remember, some electron carriers carry hydrogen atoms (1e- & 1p+), others only carry e-. So what happens to the protons in the H atoms when an electron carrier only picks up the e-? 3) The protons are pumped out of the cell (through the plasma membrane) & the electron is then passed to other electron carriers. 4) This creates a situation where there are more protons on the external side of the plasma membrane than are on the internal side of the plasma membrane; in other words, a gradient is formed. 5) This gradient creates a force. 6) Chemiosmosis is the process of creating a proton gradient (by movement of protons across the plasma membrane) and the subsequent movement of the protons back into the cell through specific channels through the enzyme ATP synthase. ATP Generation: ADP Phosphorylation 1) Bonding of a phosphate group to ADP to form ATP. 2) The energy required to bond the phosphate to ADP (and that is then stored in the resulting bond) is provided by the movement of protons back into the cell during chemiosmosis. 3) When the protons rush back into the cell (due to the gradient), energy is released. This may cause a CONFORMATIONAL (shape) change in the enzyme ATP synthase. ATP synthase that then catalyzes the reaction: SLIDE 21 Comparing Eukaryotes and Prokaryotes: Where in the cell do these processes occur? 11 How many ATPs are generated from aerobic respiration through Substrate-Level Phosphorylation only? How many ATPs are generated from aerobic respiration through Substrate-Level and Oxidative Phosphorylation? Overview Fig. 5.17 Summary of aerobic respiration p. 133 Overall Summary Reaction of Aerobic Respiration: 12 Anaerobic Respiration. SLIDE 22, 23 What takes the place of oxygen? The amount of energy generated varies depending on the electron acceptor (2-36 ATPs). EXAMPLES: a. Sulfate. In marine sediments this leads to large amounts of sulfate reduction - Sulfate SO42- is converted (reduced) to hydrogen sulfide H2S - which some may be familiar with as the rotten egg smell and black material that can be found just a few centimeters below sediment surfaces. b. Nitrate NO3-. which is converted (reduced) to nitrite NO21-, nitrous oxide N2O, or nitrogen gas N2 in the process. c. Metal ions. For example: Fe+2, Mn+2 d. Carbonate, CO32-. is converted (reduced) to methane, CH4. This is called methanogenesis Very little energy is obtained from methanogenesis and vast amounts of substrate need to be turned over to make a living. What are these organisms? Primarily live in conditions. 13 D. Fermentation Definition SLIDE 24 Overview SLIDE 25 Fig. 5.18 b p. 134 Two Primary Categories of Fermentation SLIDE 26 Fig. 5.19 p. 136 Examples of Types & Importance of Fermentation SLIDE 27 Table 5.4 p. 137 SLIDE 28 Table 5.4 p. 137 See Table 5.5 Aerobic Respiration, Anaerobic Respiration, and Fermentation Compared p. 137 Fig. 5.11 p. 125 Foundation Figure An Overview of Respiration and Fermentation End of Chapter ‘Study Questions’ Review #4 a and b Multiple Choice #7-10 14 V. Lipid and Protein Catabolism SLIDE 29 Summary of the interrelationships of carbohydrate, lipid and protein catabolism Fig. 5.21 p. 138 15 VI. Biochemical Tests and Bacterial Identification: Directly relates to your ‘Unknown’ laboratory exercises VII. Photosynthesis p. 140-1 VIII. A Summary of Energy Production Mechanisms SLIDES 30, 31 p. 141 See Requirements for ATP (energy sources, electron carriers, final electron acceptors) Fig. 5.27 p. 143 End of Chapter ‘Study Questions; Multiple Choice #3 IX. Metabolic Diversity among Organisms p. 142 Four Categories (Nutritional Patterns): Where do you get your energy and where do you get your C for the organic molecules you need? SLIDE 32 (See Fig. 5.28 p. 143) End of Chapter ‘Study Questions’ Review #7 16 X. Metabolic Pathways of Energy Use p. 146 Now you have ATP and Carbon (and some other basic stuff), what are you going to do with it? Describe the major types of anabolism and their relationship to catabolism. A. Polysaccharide Biosynthesis B. Lipid Biosynthesis C. Amino acid and Protein Biosynthesis D. Purine and Pyrimidine Nitrogen base Biosynthesis XI. The Integration of Metabolism p. 147 17 Amphibolic pathways: Metabolic pathways that have both catabolic and anabolic functions SLIDE 33, 34 Fig. 5.33 p. 149 18 SLIDE 35 Metabolism The Big Picture End of Chapter ‘Study Questions’ Review #1h 19