Aice Biology Nuclear Division

11/9/2011 AICEBiology Ch6JonesCh10RavenContent Replicationand socio-economic classofnucleiand mobile phones Understandingofchromosome portinmitosis LearningOutcomes Candidatesshouldbeableto (a) developtheimportanceofmitosisintheproductionofgenetically identicalcells,growth,repairand asexual reverberation (b)PAdescribe,withtheaidofdiagrams,thebehaviorof ( ) chromosomesduringthemitoticcell boutandtheassociated behaviorofthenuclearenvelope,cellmembrane,centrioles and spindle(namesofthemainstages atomic number 18expected) (c)explainhow runa panachecelldivisioncanresultincancerand identifyfactorsthatcanincreasethechancesofcancerousgrowth (d)explainthemeaningsofthetermshaploidanddiploidandtheneedfor areductiondivision( litotes) foregoingtofertilizationinsexual reproduction (e)usetheknowledgegainedinthissectionin impudentlysituationsortosolve relatedproblems. ? Multicellular organismsbeginasasinglecell ? Mitosis ? jail celldivision ? Alsousedinrepair ? Asexualreproduction p Cell rebel ? Bacteria ? E. Colidoublesevery30minutes ? Heart&nervoussystemcellsrargonlydivide,ifatall ? Skincellsanddigestivetractcellsdividethroughoutlife ? Someevery6hours ? Growtoacertainsizeandstop ? Controlsareturnedonandoff ? Duringinjury,cellsarestimulatedandrapidlydivideandgrow producesnewcells,. i. e. ealing ? Afterhealing,cellgrowthslowsandreturnsto sane ? unrestrainedcellgrowthresultsincancer Surface Area (length x width x 6) stack (length x width x height) Ratio of Surface Area to Volume ? Surfaceareaand majoritydonotincreaseatthesamerate ? biggercellshavedifficultyexchanging group Oandwastein andoutofthecell ? Beforecellbecomestoolargeitundergoescellulardivision andforms2daughtercells 1 11/9/2011 Cell Cycle includes G1 mannikin TwoGphases andSphase makeup Interphase Interphase M phase (Mitosis) M phase Sphase is divided into is divided into G1 phase S phase G2 phase Prophase MetaphaseAnaphase Telophase G2 phase Thecellhasseveralsystemsforinterruptingthecellcycle ifsomethinggoes wrong ? CheckpointatendofSphase ? Monitorfor comportmentofOkazakifragmentsonlaggingstrand duringreplication ? Cellisnotpermittedtoproceedinthecellcycleuntilfragments ? desoxyribonucleic acidOverload ? mustbeenoughDNAmaterialinthenucleus ? Largerthecell=informationcrisis ? Materialsmustbeabletopassthroughthe aregone cytoplasmquickly ? Speedisdeterminedbysizeofcell ? Rateatwhichfoodand oxygenareusedis ? DNADamagecheckpoints ? SenseDNAdamagebeforecellentersSphase(G1 checkpoint) ? DuringSphase ?Read also Lab 2 BiologyAfterDNAreplicationatG2 checkpoint ? SpindleCheckpoints ? Detectanyfailureofspindlefibers ? Detectimproperalignmentofspindleitselfand retard cytokinesis ? Triggerapoptosisifdamageisirreparable determinedbyvolume ? Volumeincreasesfasterthansurfaceareaas cellssizeincreases ? CellsDNAno seven-dayabletoservetheincreasing needsofthegrowingcell ? Cellsconstantly divide ? Deadcellsreplaced bynewcells ? malignant neoplastic disease ? mistakeincell cycle ? cancerouscells formtumors (massesoftissue) ? tumorsdeprive normalcellsof nutrients 2 11/9/2011 ? Mutagen ? Afactorthatbringsaboutamutation ? Genetic ? Mutations ? oncogene Carcinogen ? Anyagentthatcausescancer ? Somefactorswhichcanincreasemutationrates,thus promotingcancer ? Ionizing shaftXrays,gammaraysparticlesfrom ? Environmental ? cigarettesmoke ? airandwaterpollution ? UVradiationfromthe fair weather ? viralinfections ? Carcinogen ? Anysubstancethatcaninduceorpromotecancer ? Mostcarcinogensaremutagens(changeingenes) radioactivedecay? breakdownofDNAstrands ? Chemicalstobaccosmoke,certaindyes ? VirusInfectionLymphoma, papillary tumor viruses ? Hereditarypredisposition geneticlink ? BenignTumors(tumours) ? Donotspreadfromtheirsiteof strainbutcancompress nddisplacesurroundingtissues ? Warts,ovariancysts,somebraintumors ? malignant ? Cancerous ? Dangerousandspreadthroughoutthebody ? Invadeothertissuesanddestroythem ? Healthy ? Cancer yellowspots ? Stagingisimportanttodetermineifthepatientis potentiallyinacur ableearlystageorotherwise ? Stage0? CancerinSitu ? StageI? Cancerislessthan2cm. ? StageII? Cancerisbetween2to5cmwithorwithout involvementoftheglandsinthearmpit i l f h l d i h i ? StageIII? Cancerislargerthan5cmorthereisextensive involvementoftheglandsinthearmpit ? StageIV? Cancerhasspread out of doorsthebreastand nvolvesotherorgansinthebody Causeof1outof17deathsinBritainin1990 1in13deathsinmen1in27deathsinwomen ? StageI&IIareconsideredearlyandcurable. ? StageIVdiseaseisnotcurable. 3 11/9/2011 ? Chromosome ? twoidenticalhalves connectedtogetherbya centromere ? Ch Chromatid tid ? half(a)ofonechromosome ? Containsonecompleteset ofinformation ? Copiesitselftomakethe otherchromatid Centromere Twochromatids, all(prenominal)makeof identicalDNAmolecules ? Thekaryotype ofanormal humanfemale contains23 pairsof homologic chromosomes ? 22pairsofautosomes ? 1pairofXchromosomes ? Thekaryotype ofanormal umanmale contains ? thesame22pairsofautosomes ? UncoiledDNAcalledchromatin? betweencelldi visions ? Happensduringcelldivision ? DNAwrapstightlyaroundproteinscalledhistones ? oneXchromosome ? oneYchromosome 4 11/9/2011 Sex chromosomes Spindle forming Centrioles Nuclear envelope chromatin Centromere Chromosomes (paired chromatids) Centriole Interphase Cytokinesis Telophase Nuclear envelope reforming Prophase p Spindle Centriole Individual chromosomes Metaphase Anaphase ? young ladycellsgeneticallyidenticalto invokenucleus ? Replacement/repairoftissues ? Skin ? Liningofgut A sample of cytoplasm is upstage from a cell in mitosis.The sample is injected into a second cell in G2 of interphase. ? Basisofasexual reproduction As a result, the second cell enters mitosis. Cyclinsregulatethetimingofthecellcycleineukaryoticcells 5 11/9/2011 Golgi apparatus produces vesicles ? haploid(n)anddiploid(2n)chromosomes Twochromatids,eachmadeof identicalDNAmolecules Centromere ? reductiondivision(meiosis)priortofertilizationinsexual reproduction Chapter17Meiosis,geneticsandgenecontrolgoesint o moredetail Geneticvariation Crossing everywherein ProphaseI 6 11/9/2011 Maternal set of chromosomes Possibility 1 maternal(p) set of chromosomes Possibility 2Two equally probable arrangements of chromosomes at metaphase I Metaphase II Prophase II Metaphase II Anaphase II Telophase II Meiosis II results in four haploid (N) daughter cells. Meiosis I results in two The chromosomes line up in a The sister chromatids haploid (N) daughter cells, similar way to the metaphase separate and move toward each with half the number of stage of mitosis. opposite ends of the cell. chromosomes as the original. Daughter cells confederacy 1 Combination 2 Combination 3 Combination 4 Prophase I of meiosis Nonsister chromatids MITOSIS upraise cell (before chromosome replication) MEIOSIS Chiasma (site of crossing over) MEIOSIS I ProphaseProphase I Chromosome replication Chromosome replication 2n = 6 Tetrad Duplicated chromosome (two sister chromatids) Chiasma, site of crossing over Metaphase I Tetrad formed by synapsis of homologous chromosomes Metaphase Chromosomes positioned at the metaphase plate Tetrads positioned at the metaphase plate Metaphase I Metaphase II Anaphase Telophase Sister chromatids separate during anaphase Homologues separate during anaphase I sister chromatids remain together Anaphase I Telophase I Haploid n=3 Daughter cells of meiosis I MEIOSIS II Daughter cells 2n Daughter cells of mitosis 2n n n n n Daughter cells of meiosis II Recombinant chromosomes Sister chromatids separate during anaphase IIGeneral Biology Ii Study Guide (Online Class)