cell-division-cancer癌癥和細胞分裂

celldivisioncancer癌癥和細胞分裂celldivisioncancer癌癥和細胞分裂celldivisioncancer癌癥和細胞分裂Reproductionpresentsamajorproblemforcellsandorganisms:(howcaninformationbetransmittedfaithfullytoprogeny)IIIIIIIV=onebitofgeneticinformationcelldivisioncancer癌癥和細胞分裂cel1Reproductionpresentsamajorproblemforcellsandorganisms:(howcaninformationbetransmittedfaithfullytoprogeny)IIIIIIIV=onebitofgeneticinformationReproductionpresentsamajor2=onebitofgeneticinformationTheinformationtransferproblembecomesmorechallengingasmorebitsofinformationareincorporatedintotheorganism=onebitofTheinformationtr3Oneoflife’ssolutionstothischallenge:“Package”thebitsofinformationintosingleunitscalledchromosomes=onebitofgeneticinformationOneoflife’ssolutionstothi4chromosomesPackagingofgeneticmaterialinprokaryotesandeukaryotesprokaryotecelleukaryotecellchromosomesPackagingofgeneti5Fig2.4Thestructureofahighlycondensed,replicatedchromosome.?2003JohnWileyandSonsPublishersFig2.4Thestructureofahig6AChromosomeAChromosome7BASICGENETICSEachcellinthehumanbodycontainstwosetsof23chromosomesMitosisidenticallyreplicatesthisinformationEachcellthereforehasthesamegeneticmaterialReproductivecellsonlyhaveonesetofchromosomes.ThesecombinetomakeanewpersonwithdifferentgeneticmaterialtobothparentsBASICGENETICS8Thecellcycle.?2003JohnWileyandSonsPublishersThecellcycle.?2003JohnWil9MitosisTheStagesoftheCellCycleinterphaseG1SG2CelldivisionMMitosisTheStagesoftheCell10MstageMitoticStageThenucleusandcytoplasmsplittomaketwonewcellsknownasDIPLOIDcellsMstage11Everydividingtissuecellinthebodyisalwaysatastageofthecellcycle.Whetheritisat:-STAGESOFMITOSISCytokinesisThusenablingthebodytocontinuouslymakenewbodytissueforgrowthandrepair.DiagramshowingtheStagesofMitosisProphaseMetaphaseAnaphaseTelophaseInterphaseEverydividingtissuecellin12ProphaseMetaphaseAnaphaseTelophaseTheStagesofMitosisInterphaseProphaseMetaphaseAnaphaseTelop13TheSpindle

Aspindleisawebtypestructuremadeupofmicrotubulefibres.Itisessentialformitosisbecauseitarrangesthechromosomesintotheircorrectpositionsinpreparationforcelldivision.MitoticcentreMicrotubuleAcellatmetaphaseaspindleTheSpindleAspindleisaw14ChromosomesattachedtospindleduringnucleardivisionChromosomesattachedtospindl15INTERPHASEAfteracellhasdivided,thetwonewcellsbegintheprocessagain,thecellsatthisstageareinInterphase.CellcycleItisdividedintothreeministages:-G1SG2INTERPHASEAfteracellhasdiv16EukaryoticchromsomereplicatingEukaryoticchromsomereplicati17PROPHASEThechromatin(unravelledDNA)inthenucleus,condensestoformpairsofchromosomes.Thecentriolesmovetooppositeendsofthenucleus.AsthisishappeningthenucleolusbeginstobreakdownNuclearmembranebeginstobreakdownPROPHASEThechromatin(unravel18Prophase

Chromatincondenses(rememberthatchromatin/DNAreplicateduringInterphase),thenuclearenvelopedissolves,centrioles(ifpresent)divideandmigrate,thespindleforms.Prophase

Chromatincondenses(19METAPHASEThespindlebecomesfullydevelopedThenuclearmembranehascompletelygoneThechromatidpairsplacethemselvesontoindividualfibresandarealignedalongthecentreofthespindleMETAPHASEThespindlebecomesf20ANAPHASEThechromatidpairsaresplitintotwo(Thisisdonebymovementofthespindlefibres)ThepairsthentraveltooppositeendsofthespindleThehalvedchromatidsarenowcalledchromosomesANAPHASEThechromatidpairsar21TELOPHASETwonewnucleiareformedwhenthechromosomesreachtheoppositepolesofthecellThenuclearmembraneisformed-thenucleolusreappearsThechromosomesdisperseinthenucleusTELOPHASETwonewnucleiarefo22REMEMBER!InterphaseProphaseMetaphaseAnaphaseTelophase

IPMATREMEMBER!InterphaseIPMAT23cell-division-cancer癌癥和細胞分裂24cell-division-cancer癌癥和細胞分裂25cell-division-cancer癌癥和細胞分裂26cell-division-cancer癌癥和細胞分裂27Mitosisinanimalcells.?2003JohnWileyandSonsPublishersMitosisinanimalcells.?200328cell-division-cancer癌癥和細胞分裂29CYTOKINESISLiterallymeans,divisionofthe

cytoplasmMitosisisthesplittingofthenucleus.CytokinesisisthesplittingofcytoplasmItusuallybeginsduringANAPHASECYTOKINESISLiterallymeans,30Observedwithplacecontrastmicroscopy.TheworkofShinyaInoueandRudolfOldenbourge.TheMitosisWorldWebsite.

TheworkofMrPaulMaddox.TheMitosisWorldwebsite.

Kangarooepithelialkidneycellgoingthroughmitoticdivision.MitosisandcellplateformationinaflattenedendospermcelloftheAfricanbloodlilyHaementhusKatherininae.Observedwithplacecontrastm31CellTurnover-ThespeedofmitosisAlthoughyoumayhaveseenaspeededupvideoofmitosisinaction.Onefullcyclecanvarybetweenacoupleofminutestodays.Forexampleskinandepithelialcellshavearapidturnoverinthehumanbodyinordertoreplacetheonesconstantlybeingwornaway.Cellswhichmakeuporganssuchastheeyeandthebrain,neednotmultiplyasoftenoncetheyreachadultsize.ClickhereformoviesCellTurnover-Thespeedofm32Organswhichneedtoproducenewcellscontinuouslyhavethehighestturnover.

Forexample:-Bonemarrow-producingreplacementbloodcellsThetestes-producingsemenOrganswhichneedt