分类细菌和病毒的极光高中课件 38页

Classification,Bacteria,andVirusesBiology\nClassificationTaxonomyis:thescienceofnamingandclassifyingorganismsLinnaeusdevelopedatwo-wordnamingsystemscalledbinomialnomenclature.Eachspeciesisassignedatwo-partscientificname.Writteninitalic,withjustthefirstwordcapitalizedFirstword:GenusSecondword:speciesForexamples,humansareHomosapiens\nClassificationOvertime,Linnaeus’sclassification/taxonomysystemexpandedtoorganizelivingthingsfurther.Thisincludes:KingdomPhlyumClassOrderFamilyGenusSpecies\nClassification\nClassificationCladogram-amodelusedbyevolutionarybiologiststorepresentevolutionaryhistoryamongspeciesClade-agroupofspeciesthatincludesasinglecommonancestorandalldescendantsofthatancestor.Derivedcharacter-atraitthataroseinthemostrecentcommonancestorofaparticularlineageandwaspassedalongtoitsdescendants.\nClassification\nClassificationClassificationhasbroadenbeyondkingdomstodomains:BacteriaArchaeaEukarya\nDomainBacteriaCharacteristics:UnicellularprokaryotesPeptidoglycancellwall,cellmembrane,ribosomesNomembrane-boundorganellesNakedDNA,singlecircularchromosomeAsexualreproduction=binaryfissionHeterotrophs,photoautotrophs,chemoautotrophsRods,spheres,spirals:Grampositiveandgramnegative\nDomainBacteriaDomainBacteriaExamplesinclude:Bacillus,E.Coli,Streptococcus\nDomainArchaeaCharacteristicsUnicellularprokaryotesCellwall(nopeptidoglycans),cellmembrane,ribosomes,nomembrane-boundorganellesDNA+histoneproteins,singlecircularchromosomeAsexualreproduction=binaryfissionExtremophiles:halophiles,thermophiles,methanogens\nDomainArchaeaExamples:Methancoccus,Halobacterium,Thermoproteus\nDomainEukaryaExamples:Animals,Plants,Fungi,Protists*WewillexploreeachKingdominmoredetailthroughouttheremainderoftheyear\nProkaryotesAllbacteriaareprokaryotes-unicellularorganismthatlackanucleus.smallcells(about1-10µm)thatdonothavemembrane-boundorganellesFoundinbacteriaandarchaebacteria\nProkaryotesBacteriaSurroundedbycellwallwhichcontainspeptidoglycanArchaebacteriaLooksimilartobacteriaLackpeptidoglycanincellwallsLiveinharshenvironments\nBacteriaProkaryoticCellStructures:Nucleoidregion–partoftheprokaryoticcellwheretheDNAisfoundCellmembrane–innermostcoveringofthecellCellwall–outsideofcellmembraneCapsule–outsideofthecellwall,protectivecovering(notallbacteriahaveit)\nBacteriaProkaryoticCellStructures(continued):Flagella(sing.Flagellum)–long,whiplikestructurethatmovesbacteriaEndosporeAthickwallthatenclosesDNA;resistancestructureenablingbacteriatosurviveharshconditionsPili–short,hair-likeprojectionusedtosticktoothersurfacesandforconjugation(exchangeofgeneticmaterialsbetweenbacteria)Cytoplasm–jelly-likefluidthatdissolvessubstancesandholdsorganellesRibosomes–organellesthatmakeproteinsinthecytoplasm\nBacteria\nBacterialcellwallsInbacteria,thecellwallconsistsofaprotein/carbohydratecomplexcalledcarbohydratecalledpeptidoglycan.Theyareclassifiedbasedontheircellwalls:GrampositivebacteriaMorepeptidoglycanincellwallsAppearpurpleunderthemicroscopeaftergramstainGramnegativebacteriaHavelesspeptidoglycanincellwallsHaveoutermembraneApperpinkunderthemicroscopeaftergramstain\nBacteria-shapesBacilliRod-shapedCocciSpherical-shapedaseither:Staph-clustersStrep-chainsSpirillaSpiral-shaped\nBacteria-shapes\nBacteria-modesofnutritionHeterotrophConsumeotherorganisms:ClostridiumPhotoheterotrophConsumeotherorganismsandcanuselightenergy:RhodobacterPhotoautotrophUselightenergytomakecarboncompounds;CyanobacteriaChemoautotrophUsechemicals,likeammoniaandhydrogensulfide,toobtainenergy;Nitrogen-fixingbacteria\nBacteria-Aerobic,Anaerobic,andFacultativeAnaerobesAerobicNeedoxygentoliveAnaerobicCannotlivewithoxygenFacultativeanaerobesCanlivewithorwithoutoxygen\nBacteria-BinaryFissionBinaryfissionProcessbyprokaryotesreproducebycelldivision.Steps:Duplicationofchromosomesandseparationofcopies.CellelongatesDividesintotwodaughtercells\nBacteria-BinaryFission\nBacteriaandDiseasePathology-thestudyofdiseasecausedbypathogens(microorganism—virusesorprokaryotes–thatcausedisease)\nBacteriaanddiseaseBacteriacausediseasebydestroyinglivingcellsorbyreleasingchemicalsthatupsethomeostasis.DamaginghosttissueReleasingtoxins\nBacteriaandDiseaseBacteriacanbecontrolledvia:PhysicalremovalDisinfectantsFoodstorageFoodprocessingSterilizationbyheat\nBacteriaandDiseaseBacterialdiseasescanbetreatedvia-AntibioticsBlocksthegrowthandreproductionofbacteriaExamples:penicillin,streptomycin,andtetracycline\nBacteriaandDiseasePreventionofabacterialdiseasevia:vaccine-Apreparationofweakenedorkilledpathogensorinactivatedtoxinsthatpromptthebodytoproduceimmunitytoaspecificdiseaseuponinjection.\nVirusVirusAnonlivingparticlemadeofproteinsandnucleicacids.Canreproduceonlybyinfectinglivingcells.HavenocytoplasmororganellesCannotcarryoutmetabolismorhomeostasisCan’tgrowlikecells.\nVirusVirusesconsistof…Capsid-proteincoatsurroundingavirusSomeviruseshaveanenvelopthatsurroundsthecapsid(Influenza)Nucleicacids(eitherDNAorRNA)\nVirusShapesHelical-TobaccoMosaicVirus(containsRNA)Polyhedral-Herpes(containsDNA),ChickenPox(containsDNA),Polio(containsRNA)Spherical(enveloped)-Influenza(containsRNA)Bacteriophage-T4(containsDNA)BacteriophageHelicalSpherical\nVirusViralInfections-Inordertoinfectacell,avirusmustbeabletorecognizeit.Virusesmustbindtheproteinsontheircapsidspecificallytotheproteinsontheirspecifichost.Virusesthen“trick”thecelltotakeinitsgeneticmaterial.Viruseswillthenmakemultiplecopiesofthemselvesinsidethecell,ultimatelydestroyingthecell.\nVirusViralInfectionscantakeplaceintwoways-LyticinfectionLysogenicinfection\nVirusLyticInfectionThevirusinfectsacell,itreplicates,andthenewvirusesburstor“lyse”fromthecell.\nVirusLysogenicInfectionhostcellisnotimmediatelytakenoverThevirusinfectsacell,theviralDNAintegrateswithhostDNAwhereitmaystayforalongperiodoftime.TheviralDNAmultipliesasthehostcellsmultiply.Eventually,itwillbecomelytic,andtheviruseswillburstfromthecell.\nVirusesandDiseaseVirusescausediseasebydirectlydestroyinglivingcellsorbyaffectingcellularprocessesinwaysthatupsethomeostasis.Diseasesinclude:CommoncoldInfluenzaAIDSChickenpoxHepatitisWesNileVirusHPV(Humanpapillomavirus)\nVirusesandDiseaseWaystofightviruses-Hygiene-Washinghands,avoidingcontactwithsickindividuals,coughingorsneezingintoatissueoryoursleeveVaccinationsExposuretoinactiveformsofthevirusthatpromptthebodytoproduceimmunitytoaspecificdiseaseuponinjection.VectorcontrolWestNileVirusiscarriedbymosquitoes(thevector).Controllingthepopulationmosquitoescouldeliminatethespreadofthevirus.AntiviraldrugtherapyAttackvirualenzymesthatinturnslowdownorstoptheinfectioncycleofthevirus.