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Microbes Final Exam .docx

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Wilfrid Laurier University
Joel Weadge

Chapter 5 Nutrition Culture and Metabolism of Microorganismshow to make bacteria happy must coordinate chemical reactions metabolism o anabolic energy requiring o catabolic energy releasing NutritionNutrients required for growthMacronutrients o required by cells in high amounts o O H CN P S K Mg Ca Na 1 Carbon Ctypical bacterial cell is approximately 50 carbon by dry weightmajor elements in all classes of macromoleculesheterotrophs use organic carbonautotrophs use inorganic carbon CO22 Nitrogen Ntypical bacterial cell approximately 12 nitrogen by dry weight3 Phosphorous Psynthesis of nucleic acids and phospholipids 4 Sulfur Ssulfur containing amino acids cysteine and methioninevitamins eg thimine biotin lipoic acid and coenzymes A5 Potassium Krequired by enzymes for activity6 Magnesium Mgstabilizes ribosomes membranes and nucleis aciesalso required for many enzymes 7 Calcium Ca not required by all cellshelps stabilize cell walls in microbesplays key role in heat stability of endospores 8 Sodium Nanot required by all cells important for some microbesmarine organisms salty habitats Micronutrients o required by cells in low amounts 1 Iron Fe key component of cytochromes and FeS proteins in ETCanoxic conditionsferrous Fe 2 form solubleOxic conditionsferric fe3 forms insoluble mineralsSiderophores ironbinding agents produced to obtain iron from insoluble mineral form Must steal iron from humans if inside2 Growth Factorsorganic compounds required in small amounts by certain organisms amino acids purines pyrimidinesvitamins function as cofactors 3 Other trace metalsEx Manganese copper boron chromium selenium zinc o not as efficient not everymicronutrient is used by all cellssome are found in enzymes and cofactorsCulture Mediaoften made to be selective differential or both Two broad classeschemically defined exact chemical composition is known o add precise amounts of growth requirementsundefined complex uses digests of animals of plant product exact composition not entirely known o yeast extract beef extract casein milk products tryptic soy brothexamples in textOther terms Selective medium contains compounds that selectively inhibit growth of some microorganisms and not othersAntibioticsEx Media for selective isolation of Ecoli from food productsDifferential medium contains indicator which distinguishes between chemical reaction generated by different species of bacteria during growth Used for distinguishing different species of bacteriaReactive dyesPure culture contains on single type of microorganism want to avoid contamination in lab Solid and Liquid Media liquid cultures solidified by addition of gelling agentSolid media immobilizes cells allowing them to form isolated masses coloniesuse of semisolid culture allows formation of coloniescolonies can have specific morphological characteristicsAseptic Techniquemicrobes are everywheresterilization of media is criticalaseptic technique should be followed Ex Flame tube opening inoculate loop work within 30 cm of Bunsen burnerStreak Platesstart with confluent growth in first streakwork towards getting isolate coloniesalso pour plate and spread plate variations What does knowing their nutritional supplements tell us about their metabolic processesMicrobial MetabolismAmphibolic pathways reaction pathways that utilize roles of both catabolism and anabolism transfer of ATP provides a linkRecall chemical composition of a living cell is constantly changing Energyability to do work Free energyenergy released that is available to do useful work Activation energyamount of energy needed to disrupt the stable arrangement of a given molecule
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