Chapter 13Slide 2Slide 3Slide 4The Variety of Sexual Life Cycles - AnimalsThe Variety of Sexual Life Cycles - PlantsSlide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13You should now be able to:PowerPoint Lectures for Biology, Eighth EditionNeil Campbell and Jane ReeceChapter 13Chapter 13Meiosis and Sexual Life CyclesFig. 13-3APPLICATIONTECHNIQUEPair of homologousreplicated chromosomes5 µmCentromereSisterchromatidsMetaphasechromosome•In a cell in which DNA synthesis has occurred–All the chromosomes are duplicated and thus each consists of two identical sister chromatidsFigure 13.4KeyMaternal set ofchromosomes (n = 3)Paternal set ofchromosomes (n = 3)2n = 6Two sister chromatidsof one replicatedchromosomeTwo nonsisterchromatids ina homologous pairPair of homologouschromosomes(one from each set)CentromereFig. 13-5KeyHaploid (n)Diploid (2n)Haploid gametes (n = 23)Egg (n)Sperm (n)MEIOSISFERTILIZATIONOvaryTestisDiploidzygote(2n = 46)Mitosis anddevelopmentMulticellular diploidadults (2n = 46)Fig. 13-6aKeyHaploid (n)Diploid (2n)Gametesnnn2n 2nZygoteMEIOSIS FERTILIZATIONMitosisDiploidmulticellularorganism(a) AnimalsThe Variety of Sexual Life Cycles - AnimalsCopyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin CummingsKeyHaploid (n)Diploid (2n)nnnnn2n2nMitosisMitosisMitosisZygoteSporesGametesMEIOSIS FERTILIZATIONDiploidmulticellularorganism(sporophyte)Haploid multi-cellular organism(gametophyte)(b) Plants and some algaeThe Variety of Sexual Life Cycles - PlantsFig. 13-6cKeyHaploid (n)Diploid (2n)MitosisMitosisGametesZygoteHaploid unicellular ormulticellular organismMEIOSISFERTILIZATIONnnnnn2n(c) Most fungi and some protistsFig. 13-7-3InterphaseHomologous pair of chromosomesin diploid parent cellChromosomesreplicateHomologous pair of replicated chromosomesSisterchromatidsDiploid cell withreplicated chromosomesMeiosis IHomologouschromosomesseparate 1Haploid cells withreplicated chromosomes Meiosis II2Sister chromatidsseparate Haploid cells with unreplicated chromosomesMetaphase IFig. 13-8aProphase I Anaphase ITelophase I andCytokinesisCentrosome(with centriole pair)SisterchromatidsChiasmataSpindleHomologouschromosomesFragmentsof nuclearenvelopeCentromere(with kinetochore)MetaphaseplateMicrotubuleattached tokinetochoreSister chromatidsremain attachedHomologouschromosomesseparateCleavagefurrowFig. 13-8dProphase IIMetaphase IIAnaphase IITelophase II andCytokinesisSister chromatidsseparateHaploid daughter cellsformingFig. 13-9MITOSIS MEIOSISMEIOSIS IProphase IChiasmaHomologouschromosomepairChromosomereplicationParent cell2n = 6ChromosomereplicationReplicated chromosomeProphaseMetaphaseMetaphase IAnaphase ITelophase IHaploidn = 3Daughtercells ofmeiosis IAnaphaseTelophase2n2nDaughter cellsof mitosisn nnnMEIOSIS IIDaughter cells of meiosis IISUMMARYMeiosisOccurs during interphase before meiosis I beginsTwo, each including prophase, metaphase, anaphase, andtelophaseOccurs during prophase I along with crossing overbetween nonsister chromatids; resulting chiasmatahold pairs together due to sister chromatid cohesionFour, each haploid (n), containing half as many chromosomesas the parent cell; genetically different from the parentcell and from each otherProduces gametes; reduces number of chromosomes by halfand introduces genetic variability amoung the gametesMitosisOccurs during interphase beforemitosis beginsOne, including prophase, metaphase,anahase, and telophaseDoes not occurTwo, each diploid (2n) and geneticallyidentical to the parent cellEnables multicellular adult to arise fromzygote; produces cells for growth, repair,and, in some species, asexual reproductionPropertyDNAreplicationNumber ofdivisionsSynapsis ofhomologouschromosomesNumber ofdaughter cellsand geneticcompositionRole in theanimal bodyFig. 13-11-3Possibility 1Possibility 2Two equally probablearrangements ofchromosomes atmetaphase IMetaphase IIDaughtercellsCombination 1 Combination 2 Combination 3 Combination 4Fig. 13-12-5Prophase Iof meiosisPair ofhomologsNonsisterchromatidsheld togetherduring synapsisChiasmaCentromereAnaphase IAnaphase IIDaughtercellsRecombinant chromosomesTEMYou should now be able to:1. Distinguish between the following terms: somatic cell and gamete; autosome and sex chromosomes; haploid and diploid2. Describe the events that characterize each phase of meiosis3. Describe three events that occur during meiosis I but not mitosis4. Name and explain the three events that contribute to genetic variation in sexually reproducing organismsCopyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin
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