翟中和细胞生物学课件—绪论

分子细胞生物学MolecularCELLBIOLOGY主讲教师：丁明孝，陈建国，张传茂Chapter1IntroductiontothecellLearningObjectives1.AboutCellBiology2.Lookbrieflyatthehistoryofcelltheory;3.Considerthebasicpropertiesofcells;4.Comparesomecharacteristicsoftwodifferentclassesofcells:prokaryotesandeukaryotes;5.Comprehendaspeciallife:viruses1.About“CellBiology”What?Forwhy?Howtostudy?TheNIHofUSA(1988):“Whatispopularinresearchtoday？”3kindsofdiseases：cancercardiovasculardiseasesinfectiousdiseases：AIDS，hepatitis5researchfields：cellcyclecontrol；cellapoptosis；cellularsenescence；signaltransduction；DNAdamageandrepair.Whatweknow//Howweknow.ISI,USA(1997):SCI（ScienceCitationIndex）Papers:Threetopsofresearchfields:No1:Signaltransduction；No2:Cellapoptosis；No3:Genomeandpost-genomicanalysis。2.TheCellTheory:ABriefHistoryIn1665,RobertHookesawanetworkoftinyboxlikecompartmentsthatremindedhimofahoneycomb.Hecalledtheselittlecompartments“cellulae”,aLatintermmeaninglittleroom.Itisfromthiswordwegetourpresent-dayterm,cell.ThemicroscopeusedbyRobertHookeandthehoneycomb-likenetworkof“cell”hedrawedin1665ThediscoveryofcellsfollowedfromtheinventionofthemicroscopeCelltheoryhasthreebasictenets:1.Allorganismsarecomposedofoneormorecells.2.Thecellisbasicunitofstructureandfunctionforallorganisms.3.Allcellsariseonlyfrompreexistingcellsbydivision.3.Whyarecellsthebasicunitsoflife?A.Thecellisthestructuralunitoflife,Allorganismsismakeupofcells.B.Thecellisthefunctionalunitoforganisms.Allmetabolicactivityisbasedoncells.C.Thecellisthefoundationofreproduce,andthebridgeofinheritance.D.ThecellisthegrowinganddevelopingbasisoflifeHumanfetaldevelopment.(a)At5weeks,limbbuds,eyes,theheart,theliverandrudimentsofallotherorganshavestartedtodevelopintheembryo,whichisonlyabout1cmlong.(b)Growthanddevelopmentoftheoffspring,nowcalledafetus,continueduringthesecondtrimester.Thisfetusis14weeksoldandabout6cmlong.(c)Thefetusinthisphotographis20weeksold.Nowthefetusgrowstoabout30cminlength.E.Cell(nucleus)istotipotent,whichcancreateaneworganismofthesametypeAsageneralrule,thecellsofamulticellularorganismallcontainthesamesetofgenes.Foranimals,thefirstevidencethatevenhighlyspecializedcellcarryafullcomplementofgeneswasverifiedbytheexperimentoftadpolenucleitransplantingintounfertilizedeggthathadbeendeprivedofitsownnucleus.Somecandevelopswimmingtadpoles.Thisisanimalcloning.Anespeciallydramaticexampleofanimalcloningwasreportedin1997.Dollythefirstanimaleverclonedfromacellderivedfromanadult.DollyandherdaughterTheprocessofcloningDollyIsthereanypracticalvaluetosuchtechnology?4.BasicpropertiesofcellsA.Cellsarehighlycomplexandorganized,capableofself-regulation;Cellsacquireandutilizeenergy.B.Allcellssharesimilarstructure,compositionandmetabolicfeatures:Plasmamembrane,DNA/RNA,andRibosome.C.Cellscancapableofproducingmoreofthemselves,evengrowandreproduceincultureforextendedperiods.HeLacellsareculturedtumorcellsisolatedfromacancerpatientnamedHenriettaLacksin1951.Itisthefirsthumancelltobekeptincultureforlongperiodsoftimeandisstillusedtoday.JohnsHopkinsunivesity,in1951D.Cellsareabletorespondtostimuliviasurfacereceptorsthatsensechangesinthechemicalenvironment.Cellswithinplantoranimalrespondtostimulilessobviouslythansingle-celledprotist.Buttheyrespond.Theypossesreceptorsthatinteractwithsubstancesintheenvironmentinhighlyspecificways.Forexample,thereceptoronthecellsurfacecanrespondtohormonesandgrowthfactors.5.TheSizeofCellsa)diameterb)Measuredinunitsofmicrometers:1um=10-6meternanometers:1nm=10-9meterc)Cellsizeislimited:nucleus/cytoplasmratio;surfacearea/volumeratio;substancescanefficientlytravelthroughthecytoplasmviadiffusion.6.Twofundamentallydifferentclassesofcells:ProkaryotesandeukaryotesA.Prokaryoticandeukaryoticcellsaredistinguishedbythesizeandthetypesofinternalstructures,ororganelles,especiallyifthereisnuclearenvelope.Bacteriaareprokaryotes,theyarose3.5billionyearsago;Protists,fungi,plants,andanimalsareeukaryotes.Thefirsteukaryotesarose1.5billionyearsago.B.Characteristicsthatdistinguishprokaryoticandeukaryoticcells(1)Complexity:Prokaryotesarerelativelysimple,eukaryotesaremorecomplexinstructureandfunctionpp.36Table2-2;2-3(2)Geneticmaterial:AllCellsStoreTheirHereditaryInformationintheSameLinerChemicalCode(DNA)a.Packaging:Prokaryoteshaveanucleoidregionwhereasekukaryotehaveatrue,membrane-boundnucleus.b.Amount:Eukaryoteshaveseveralordersofmagnitudemoregeneticmaterialthanprokaryotes.c.Form:EukaryoteshavemanychromosomesthataremadeofbothDNAandproteinwhereasprokaryoteshaveasingleDNAchromosomea.Packaging:Prokaryoteshaveanucleoidregionwhereasekukaryotehaveatrue,membrane-boundnucleus.(bacterinm:0.25-3.0mm,toencodebetweenseveralhundredandseveralthousandproteins,Thesimplestknowncellshavejustunder500genes).b.Amount:Eukaryoteshaveseveralordersofmagnitudemoregeneticmaterialthanprokaryotes.(yeast:4.6mmDNA,encodingabout6200proteins)c.Form:EukaryoteshavemanychromosomesthataremadeofbothDNAandproteinwhereasprokaryoteshaveasingle,“naked”DNAchromosome(3)Cytoplasm:Eukaryoteshavemembrane-boundorganellesandcytoskeletalproteins;prokaryoteshaveneither.Bot