细胞生物学课件 29页

分子细胞生物学MolecularCELLBIOLOGY\nChapter1IntroductiontothecellLearningObjectives1.AboutCellBiology2.Lookbrieflyatthehistoryofcelltheory;3.Considerthebasicpropertiesofcells;4.Comparesomecharacteristicsoftwodifferentclassesofcells:prokaryotesandeukaryotes;5.Comprehendaspeciallife:viruses\n1.About“CellBiology”What?Forwhy?Howtostudy?TheNIHofUSA(1988):“Whatispopularinresearchtoday？”3kindsofdiseases：cancercardiovasculardiseasesinfectiousdiseases：AIDS，hepatitis5researchfields：cellcyclecontrol；cellapoptosis；cellularsenescence；signaltransduction；DNAdamageandrepair.Whatweknow//Howweknow.\nISI,USA(1997):SCI（ScienceCitationIndex）Papers:Threetopsofresearchfields:No1:Signaltransduction；No2:Cellapoptosis；No3:Genomeandpost-genomicanalysis。\n2.TheCellTheory:ABriefHistoryIn1665,RobertHookesawanetworkoftinyboxlikecompartmentsthatremindedhimofahoneycomb.Hecalledtheselittlecompartments“cellulae”,aLatintermmeaninglittleroom.Itisfromthiswordwegetourpresent-dayterm,cell.ThemicroscopeusedbyRobertHookeandthehoneycomb-likenetworkof“cell”hedrawedin1665Thediscoveryofcellsfollowedfromtheinventionofthemicroscope\nCelltheoryhasthreebasictenets:1.Allorganismsarecomposedofoneormorecells.2.Thecellisbasicunitofstructureandfunctionforallorganisms.3.Allcellsariseonlyfrompreexistingcellsbydivision.\n3.Whyarecellsthebasicunitsoflife?A.Thecellisthestructuralunitoflife,Allorganismsismakeupofcells.\nB.Thecellisthefunctionalunitoforganisms.Allmetabolicactivityisbasedoncells.\nC.Thecellisthefoundationofreproduce,andthebridgeofinheritance.\nD.ThecellisthegrowinganddevelopingbasisoflifeHumanfetaldevelopment.(a)At5weeks,limbbuds,eyes,theheart,theliverandrudimentsofallotherorganshavestartedtodevelopintheembryo,whichisonlyabout1cmlong.(b)Growthanddevelopmentoftheoffspring,nowcalledafetus,continueduringthesecondtrimester.Thisfetusis14weeksoldandabout6cmlong.(c)Thefetusinthisphotographis20weeksold.Nowthefetusgrowstoabout30cminlength.\nE.Cell(nucleus)istotipotent,whichcancreateaneworganismofthesametypeAsageneralrule,thecellsofamulticellularorganismallcontainthesamesetofgenes.Foranimals,thefirstevidencethatevenhighlyspecializedcellcarryafullcomplementofgeneswasverifiedbytheexperimentoftadpolenucleitransplantingintounfertilizedeggthathadbeendeprivedofitsownnucleus.Somecandevelopswimmingtadpoles.Thisisanimalcloning.Anespeciallydramaticexampleofanimalcloningwasreportedin1997.Dollythefirstanimaleverclonedfromacellderivedfromanadult.\nDollyandherdaughterBonnieTheprocessofcloningDollyIsthereanypracticalvaluetosuchtechnology?\n4.BasicpropertiesofcellsCellsarehighlycomplexandorganized,capableofself-regulation;Cellsacquireandutilizeenergy.B.Allcellssharesimilarstructure,compositionandmetabolicfeatures:Plasmamembrane,DNA/RNA,andRibosome.\nC.Cellscancapableofproducingmoreofthemselves,evengrowandreproduceincultureforextendedperiods.HeLacellsareculturedtumorcellsisolatedfromacancerpatientnamedHenriettaLacksin1951.Itisthefirsthumancelltobekeptincultureforlongperiodsoftimeandisstillusedtoday.JohnsHopkinsunivesity,in1951\nD.Cellsareabletorespondtostimuliviasurfacereceptorsthatsensechangesinthechemicalenvironment.Cellswithinplantoranimalrespondtostimulilessobviouslythansingle-celledprotist.Buttheyrespond.Theypossesreceptorsthatinteractwithsubstancesintheenvironmentinhighlyspecificways.Forexample,thereceptoronthecellsurfacecanrespondtohormonesandgrowthfactors.\n5.TheSizeofCellsdiameterMeasuredinunitsofmicrometers:1um=10-6meternanometers:1nm=10-9meterc)Cellsizeislimited:nucleus/cytoplasmratio;surfacearea/volumeratio;substancescanefficientlytravelthroughthecytoplasmviadiffusion.\n6.Twofundamentallydifferentclassesofcells:ProkaryotesandeukaryotesA.Prokaryoticandeukaryoticcellsaredistinguishedbythesizeandthetypesofinternalstructures,ororganelles,especiallyifthereisnuclearenvelope.Bacteriaareprokaryotes,theyarose3.5billionyearsago;Protists,fungi,plants,andanimalsareeukaryotes.Thefirsteukaryotesarose1.5billionyearsago.\nB.CharacteristicsthatdistinguishprokaryoticandeukaryoticcellsComplexity:Prokaryotesarerelativelysimple,eukaryotesaremorecomplexinstructureandfunction\n(2)Geneticmaterial:AllCellsStoreTheirHereditaryInformationintheSameLinerChemicalCode(DNA)Packaging:Prokaryoteshaveanucleoidregionwhereasekukaryotehaveatrue,membrane-boundnucleus.b.Amount:Eukaryoteshaveseveralordersofmagnitudemoregeneticmaterialthanprokaryotes.c.Form:EukaryoteshavemanychromosomesthataremadeofbothDNAandproteinwhereasprokaryoteshaveasingleDNAchromosomePackaging:Prokaryoteshaveanucleoidregionwhereasekukaryotehaveatrue,membrane-boundnucleus.b.Amount:Eukaryoteshaveseveralordersofmagnitudemoregeneticmaterialthanprokaryotes.(bacterinm:0.25-3.0mm,toencodebetweenseveralhundredandseveralthousandproteins,thesimplestknowncellshavejustunder500genes.Yeast:4.6mmDNA,encodingabout6200proteins)c.Form:EukaryoteshavemanychromosomesthataremadeofbothDNAandproteinwhereasprokaryoteshaveasingle,“naked”DNAchromosome\n(3)Cytoplasm:Eukaryoteshavemembrane-boundorganellesandcytoskeletalproteins;prokaryoteshaveneither.Bothhaveribosomes,althoughtheydifferinsize.(4)Cellularreproduction:Eukaryotesdividebymitosis;prokaryotesdividebysimplefission.(5)Locomotion:Eukaryotesusebothcytoplasmicmovement,andciliaandflagella;prokaryoteshaveflagella,buttheydifferinbothformandmechanismfromeukaryoticflagella.\nThedifferencebetweenprokaryoticandeukaryoticflagelaFlagellinHumansperm\nC.ThreestructuralsystemsinEukaryotes:\n7.TypesofProkaryoticCells:TwoSubkingdomsTreeoflifehasthreeprimarybranches.A.SubkingdomArchaeaSubkingdomBacteriaMostBacteriaandArchaeahave1000-4000genesThesmallestknowncells---theMycoplasma0.1～0.3μm;smallestgenome:482genes,minimalessentialgene：256\n\n8.VirusesVirusdiversity1.Virusesarepathogensfirstdescribedinthelate1800s.2.Viralstructure:a)Thegeneticmaterial:Single-ordouble-stradedDNAorRNA.b)obligatoryintracellularparasites.3.Viralinfectiontypes:a)Lyticinfection;b)integratedinfection\n4.Viralorigins:a)Viruseshadtoariseaftertheirhostsevolved;b)Virusesprobablyaroseasfragmentsofhostchromosomes.5.Viroids6.prion\n9.ReferencebookAlbertsBetal.EssentialCellBiology.NewYorkandLondon：Garlandpublishing，Inc.1998AlbertsBetal.MolecuarBiologyoftheCell,3rded.NewYorkandLondon：GarlandPublishing，Inc.1994;3rd2002.BeckerW.M.etal.TheWorldoftheCell.FourthEd.TheBenjamin/CummingsPublishingCompany.2000.GeraldKarp.CellandMolecularBiology：conceptsandexperiments，2ndEdition.PublishedbyJohnWiley&Sons,Inc.1999GeraldKarp.CellandMolecularBiology：conceptsandexperiments，3rdEdition.PublishedbyJohnWiley&Sons,Inc.2002LodishH.etal.MolecularCellBiology.4thEd.ScientificAmericanBooks,Inc.2000.\n\nTHANKS!