分子细胞生物学

分子细胞生物学MolecularCELLBIOLOGY 主讲教师 丁明孝 陈建国 张传茂 Chapter1 Introductiontothecell LearningObjectives 1 AboutCellBiology2 Lookbrieflyatthehistoryofcelltheory 3 Considerthebasicpropertiesofcells 4 Comparesomecharacteristicsoftwodifferentclassesofcells prokaryotesandeukaryotes 5 Comprehendaspeciallife viruses 1 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 ABriefHistory In1665 RobertHookesawanetworkoftinyboxlikecompartmentsthatremindedhimofahoneycomb Hecalledtheselittlecompartments cellulae aLatintermmeaninglittleroom Itisfromthiswordwegetourpresent dayterm cell ThemicroscopeusedbyRobertHookeandthehoneycomb likenetworkof cell hedrawedin1665 Thediscoveryofcellsfollowedfromtheinventionofthemicroscope Celltheoryhasthreebasictenets 1 Allorganismsarecomposedofoneormorecells 2 Thecellisbasicunitofstructureandfunctionforallorganisms 3 Allcellsariseonlyfrompreexistingcellsbydivision 3 Whyarecellsthebasicunitsoflife A Thecellisthestructuralunitoflife Allorganismsismakeupofcells B Thecellisthefunctionalunitoforganisms Allmetabolicactivityisbasedoncells C Thecellisthefoundationofreproduce andthebridgeofinheritance D Thecellisthegrowinganddevelopingbasisoflife Humanfetaldevelopment a At5weeks limbbuds eyes theheart theliverandrudimentsofallotherorganshavestartedtodevelopintheembryo whichisonlyabout1cmlong b Growthanddevelopmentoftheoffspring nowcalledafetus continueduringthesecondtrimester Thisfetusis14weeksoldandabout6cmlong c Thefetusinthisphotographis20weeksold Nowthefetusgrowstoabout30cminlength E Cell nucleus istotipotent whichcancreateaneworganismofthesametype Asageneralrule thecellsofamulticellularorganismallcontainthesamesetofgenes Foranimals thefirstevidencethatevenhighlyspecializedcellcarryafullcomplementofgeneswasverifiedbytheexperimentoftadpolenucleitransplantingintounfertilizedeggthathadbeendeprivedofitsownnucleus Somecandevelopswimmingtadpoles Thisisanimalcloning Anespeciallydramaticexampleofanimalcloningwasreportedin1997 Dollythefirstanimaleverclonedfromacellderivedfromanadult Dollyandherdaughter TheprocessofcloningDolly Isthereanypracticalvaluetosuchtechnology 4 Basicpropertiesofcells Cellsarehighlycomplexandorganized capableofself regulation Cellsacquireandutilizeenergy B Allcellssharesimilarstructure compositionandmetabolicfeatures Plasmamembrane DNA RNA andRibosome C Cellscancapableofproducingmoreofthemselves evengrowandreproduceincultureforextendedperiods HeLacellsareculturedtumorcellsisolatedfromacancerpatientnamedHenriettaLacksin1951 Itisthefirsthumancelltobekeptincultureforlongperiodsoftimeandisstillusedtoday JohnsHopkinsunivesity in1951 D Cellsareabletorespondtostimuliviasurfacereceptorsthatsensechangesinthechemicalenvironment Cellswithinplantoranimalrespondtostimulilessobviouslythansingle celledprotist Buttheyrespond Theypossesreceptorsthatinteractwithsubstancesintheenvironmentinhighlyspecificways Forexample thereceptoronthecellsurfacecanrespondtohormonesandgrowthfactors 5 TheSizeofCellsdiameterMeasuredinunitsofmicrometers 1um 10 6meternanometers 1nm 10 9meterc Cellsizeislimited nucleus cytoplasmratio surfacearea volumeratio substancescanefficientlytravelthroughthecytoplasmviadiffusion 6 Twofundamentallydifferentclassesofcells Prokaryotesandeukaryotes A Prokaryoticandeukaryoticcellsaredistinguishedbythesizeandthetypesofinternalstructures ororganelles especiallyifthereisnuclearenvelope Bacteriaareprokaryotes theyarose3 5billionyearsago Protists fungi plants andanimalsareeukaryotes Thefirsteukaryotesarose1 5billionyearsago B Characteristicsthatdistinguishprokaryoticandeukaryoticcells Complexity Prokaryotesarerelativelysimple eukaryotesaremorecomplexinstructureandfunction pp 36Table2 2 2 3 2 Geneticmaterial AllCellsStoreTheirHereditaryInformationintheSameLinerChemicalCode DNA Packaging Prokaryoteshaveanucleoidregionwhereasekukaryotehaveatrue membrane boundnucleus b Amount Eukaryoteshaveseveralordersofmagnitudemoregeneticmaterialthanprokaryotes c Form EukaryoteshavemanychromosomesthataremadeofbothDNAandproteinwhereasprokaryoteshaveasingleDNAchromosome 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 Bothhaveribosomes althoughtheydifferinsize 4 Cellularreproduction Eukaryotesdividebymitosis prokaryotesdividebysimplefission 5 Locomotion Eukaryotesusebothcytoplasmicmovement andciliaandflagella prokaryoteshaveflagella buttheydifferinbothformandmechanismfromeukaryoticflagella C ThreestructuralsystemsinEukaryotes Thedifferencebetweenprokaryoticandeukaryoticflagela Flagellin Humansperm 7 TypesofProkaryoticCells TwoSubkingdoms Treeoflifehasthreeprimarybranches A SubkingdomArchaeaSubkingdomBacteriaMostBacteriaandArchaeahave1000 4000genesThesmallestknowncells theMycoplasma0 1 0 3 m smallestgenome 482genes minimalessentialgene 256 8 Viruses Virusdiversity 1 Virusesarepathogensfirstdescribedinthelate1800s 2 Viralstructure a Thegeneticmaterial Single ordouble stradedDNAorRNA b obligatoryintracellularparasites 3 Viralinfectiontypes a Lyticinfection b integratedinfection 4 Viralorigins a Viruseshadtoa