Class10 - What about the Micro 310 Exam?! When? Friday...

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Unformatted text preview: What about the Micro 310 Exam?! When? Friday March 3, 10:10 Where? Right here! 131 Morrill II What? 50 multiple choice questions Bring #2 pencils! Class #10: Microbial Nutrition: Energetics of Alternative Nutritional Life Styles Biodiversity The diversity of microorganisms is HUGE! Diversity primarily due to diversity of the chemical processes Metabolism all chemical processes in a cell Metabolism all chemical processes in a cell Simple view of cell metabolism: Nutrients for biosynthesis Waste Products fermentation products (acids, alcohols, CO2); Reduced electron acceptors (e.g., H2O) ENERGY ENERGY How do microbes "make a living"?? Energy Source chemicals light CHNOPS! __________________________________________________ __________________________________________________ energy carbon Nutritional Categories Photoautotrophs Photoheterotrophs Energy source: Light Principal carbon source: CO2 Energy source: Light Principal carbon source: Organic compounds Energy source: inorganic compounds (H2, NH3, NO2, H2S, S, CO, Fe+2) Principal carbon source: CO2 Energy source: Organic compounds Principal carbon source: Organic compounds Chemolithotrophs Chemoorganotrophs _________________________________________________ __________________________________________________ __________________________________________________ Photoautotrophs Photoheterotrophs energy Nutritional Categories Energy source: Light Principal carbon source: CO2 Energy source: Light Principal carbon source: Organic compounds Energy source: inorganic compounds source (H2, NH3, NO2, H2S, S, CO, Fe+2) Principal carbon source: CO2 Energy source: Organic compounds source Principal carbon source: Organic compounds Chemolithotrophs Chemoorganotrophs _________________________________________________ __________________________________________________ __________________________________________________ carbon Nutritional Categories Photoautotrophs Photoheterotrophs carbon Energy source: Light Principal carbon source: source CO2 Energy source: Light Principal carbon source: Organic compounds Energy source: inorganic compounds (H2, NH3, NO2, H2S, S, CO, Fe+2) Principal carbon source: source Chemolithotrophs CO2 Chemoorganotrophs _________________________________________________ Energy source: Organic compounds Principal carbon source: Organic compounds __________________________________________________ __________________________________________________ Photoautotrophs carbon Nutritional Categories Energy source: Light Principal carbon source: CO2 Energy source: Light Principal carbon source: source Photoheterotrophs Organic compounds Chemolithotrophs Energy source: inorganic compounds (H2, NH3, NO2, H2S, S, CO, Fe+2) Principal carbon source: CO2 carbon Chemoorganotrophs compounds _________________________________________________ Energy source: Organic compounds Principal carbon source: Organic source We (humans) are: Photoautotrophs Photoheterotrophs Chemolithotrophs Chemoorganotrophs Trees are: Photoautotrophs Photoheterotrophs Chemolithotrophs Chemoorganotrophs Fungi (e.g., mushrooms) are: Photoautotrophs Photoheterotrophs Chemolithotrophs Chemoorganotrophs Pyrolobus is a: Photoautotroph Photoheterotroph Chemolithotroph Chemoorganotroph Hydrothermal Vents Pyrolobus Grows at 113C! Source of energy: H2, H2S Source of carbon: CO2 HYPERTHERMOPHILIC CHEMOLITHOTROPHIC ARCHAEA ________________________________________ ________________________________________ Photoautotrophs Photoheterotrophs Chemolithotrophs Energy source: Light Principal carbon source: CO2 Energy source: Light Principal carbon source: Organic compounds source: Energy source: Oxidation of inorganic compounds (H2, NH3, NO2, H2S, S, CO, Fe+2) Principal carbon source: CO2 Energy source: Organic compounds Principal carbon source: Organic compounds source Nutritional Categories Chemoorganotrophs ________________________________________ Autotroph -- an organism that is able to use CO2 as sole source of carbon; does not require preformed organic compounds for growth. Heterotroph --an organism that requires preformed organic compounds for growth. Mixotroph -- an organism that uses organic compounds as source of carbon while using inorganic compounds as electron donor (energy source). e.g., Beggiatoa Autotroph -- an organism that is able to use CO2 as sole source of carbon; does not require preformed organic compounds for growth. Heterotroph --an organism that requires preformed organic compounds for growth. ________________________________________________ Terms to Describe O2 Relations of Microorganisms ________________________________________________ Aerobes can use O2 Obligate O2 required Facultative O2 not required, growth better with O2 Microaerophilic O2 required, but at levels lower than atmospheric Anaerobes cannot use O2 Obligate (strict) O2 harmful or lethal Aerotolerant O2 tolerated but not used, growth is not better with O2 ________________________________________________ Which culture reflects the growth of E. coli (a facultative aerobe)? (a) (b) (c) (d) Which culture reflects the growth of Clostridium botulinum (an obligate anaerobe)? (a) (b) (c) (d) Microbial Nutrition: Energetics of Alternative Nutritional Life Styles Metabolism all chemical processes in a cell Most processes in cells involve chemical energy. Chemical reactions are accompanied by changes in energy. Energy The basics... Chemical reactions are accompanied by changes in energy. All forms of energy are inter-convertible... so we express energy in units of heat energy: kilocalorie (kcal) = amount of heat energy necessary to raise the temperature of 1 kilogram of water by 1C. 1 kcal = 4.184 kilojoules (kJ) Energy The basics... Chemical reactions are accompanied by changes in energy. G = free energy (energy released that is available to do useful work) G = change in free energy G' = standard free energy change = energy change for a reaction under "standard" conditions (reactants and products initially at 1 molar concentration, pH7, 25C). negative G' -- energy is released -- exergonic -- "spontaneous" positive G' -- energy is required -- endergonic Energy For example: The basics... Chemical reactions are accompanied by changes in energy. + H2 + 1/2O2 H2O G' = -238 kJ/mol + The hydrolysis of ATP is an exergonic reaction that can be used to drive endergonic reactions In General: Energy is released in exergonic reactions: A+BC+D negative G' The energy of the products ("Gf" called the "free energy of formation) < the energy of the reactants. Endergonic reactions require an input of energy: C+DA+B positive G' Energy The basics... Chemical reactions are accompanied by changes in energy. Reactions in cells usually don't run under standard conditions The concentration of the reactants and products may not equal 1 M, and a reaction could be driven the other way if products are removed. Many reactions are essentially reversible. reversible Although exergonic reactions are called "spontaneous" they may occur very slowly. slowly Enzyme Catalysis Although exergonic reactions are called "spontaneous" they may occur very slowly. slowly For example: + H2 + 1/2O2 H2O G' = -238 kJ/mol Reaction occurs very slowly; requires bond breaking Activation Energy the amount of energy required to bring all reactants to the reactive state Catalyst lowers the activation energy, increases the rate of reaction, remains unchanged itself, does not affect the free energy change Enzymes biological catalysts Enzymes biological catalysts + lower the activation energy Enzymes biological catalysts most are proteins highly specific temporarily combine with the reactants (= substrates) through weak bonds (H bonds, hydrophobic interactions) substrates bind at a site on the enzyme called the active site lowers energy of activation speeds the reaction Enzymes biological catalysts catalytic cycle of aldolase Enzymes biological catalysts Nonprotein molecules may participate in enzymatically catalyzed reactions: Prosthetic groups-bind very tightly to their enzymes and become a permanent part of the enzyme (e.g., heme group of cytochromes) Heme iron-containing prosthetic group found in cytochromes Cytochromes e- carriers usually members of etransport chains Enzymes biological catalysts Nonprotein molecules may participate in enzymatically catalyzed reactions: Prosthetic groups-bind very tightly to their enzymes and become a permanent part of the enzyme (e.g., heme group of cytochromes) Coenzymes-bind loosely to enzymes; one coenzyme may associate with several different enzymes; most coenzymes are vitamins or derivatives of vitamins (e.g., NAD+) NAD - Nicotinamide adenine dinucleotide - a coenzyme - niacin (a vitamin) is a precursor Enzymes biological catalysts Nonprotein molecules may participate in enzymatically catalyzed reactions: Prosthetic groups-bind very tightly to their enzymes and become a permanent part of the enzyme (e.g., heme group of cytochromes) Coenzymes-bind loosely to enzymes; one coenzyme may associate with several different enzymes; most coenzymes are vitamins or derivatives of vitamins (e.g., NAD+) Note: cofactors are inorganic substances such as minerals required for enzyme activity, e.g., Mg2+ Enzymes biological catalysts Enzymes are named for the substrate they bind -or for the chemical reaction which they catalyze Enzymes almost always end in '-ase' e.g., cellulase In-Class Group Problem #2 Phylogenetic relationships among all organisms have been examined by determining the differences in sequence of homologous macromolecules. Name a specific macromolecule that has been sequenced and has been used for phylogenetic studies of microorganisms. 16S ribosomal RNA Give two reasons why this molecule is useful for phylogenetic studies (other than that it can be sequenced). It is found in all cells It has the same function in all cells ...
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This note was uploaded on 04/18/2008 for the course MICROBIO 310 taught by Professor Dolan during the Spring '08 term at Univ. of Massachusetts Med. School.

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