生物很多來自unit2the cell13

1、Chapter 12 & 13Cell Division(Mitosis & Meiosis)APPLICATIONSomatic cells(nonreproductive cells)Somatic cells from MitosisTwo sets of chromosomesspermatogoniumoogoniumGametes(reproductive cells)Gametes from MeiosisOne set of chromosomesspermeggKeyHaploid (n)Diploid (2n)Haploid gametes (n = 23)Egg (n)S

2、perm (n)MEIOSISFERTILIZATIONOvaryTestisDiploidzygote(2n = 46)Mitosis anddevelopmentMulticellular diploidadults (2n = 46)KeyMaternal set ofchromosomes (n = 3)Paternal set ofchromosomes (n = 3)2n = 6CentromereTwo sister chromatidsof one replicatedchromosomeTwo nonsisterchromatids ina homologous pairPa

3、ir of homologouschromosomes(one from each set)RG-C13-Q7Homologous Chromosomes One pair of two chromosomes.Same Different: length centromere position staining pattern genes controlling the same inherited charactersone from father, one from motherTECHNIQUEPair of homologousreplicated chromosomesCentro

4、mereSisterchromatidsMetaphasechromosome5 msex chromosomes: A chromosome responsible for determining the sex of an individual. (X & Y, 2)autosomes: A chromosome that is not directly involved in determining sex. (22 pairs, or 44)Key Conceptskaryotype: A display of the chromosome pairs of a cell arrang

5、ed by size and shape.Key ConceptsKey Conceptsdiploid cell: A cell containing two sets of chromosomes (2n), one set inherited from each parent.haploid cell: A cell containing only one set of chromosomes (n).gamete: A haploid reproductive cell, such as an egg or sperm.zygote = fertilized egg: The dipl

6、oid cell produced by the union of haploid gametes during fertilization.fertilization: The union of haploid gametes to produce a diploid zygote.Key ConceptsHow to reduce?The Stages of MeiosisProphase IMetaphase IAnaphase ITelophase I andCytokinesisProphase IIMetaphase IIAnaphase IITelophase II andCyt

7、okinesisCentrosome(with centriole pair)SisterchromatidsChiasmataSpindleHomologouschromosomesFragmentsof nuclearenvelopeCentromere(with kinetochore)MetaphaseplateMicrotubuleattached tokinetochoreSister chromatidsremain attachedHomologouschromosomesseparateCleavagefurrowSister chromatidsseparateHaploi

8、d daughter cellsformingQ1: How do you separate these 12 pictures?Q2: Whats the essential property of division 1#?Q3: Whats the essential property of division 2#?Activity: Match & ReorderProphase IMetaphase ITelophase IAnaphase IProphase IIMetaphase IIAnaphase IITelophase IIThe Stages of MeiosisProph

9、ase IMetaphase IAnaphase ITelophase I andCytokinesisProphase IIMetaphase IIAnaphase IITelophase II andCytokinesisCentrosome(with centriole pair)SisterchromatidsChiasmataSpindleHomologouschromosomesFragmentsof nuclearenvelopeCentromere(with kinetochore)MetaphaseplateMicrotubuleattached tokinetochoreS

10、ister chromatidsremain attachedHomologouschromosomesseparateCleavagefurrowSister chromatidsseparateHaploid daughter cellsformingMeiosis IMeiosis IIFLASH 13-1InterphaseHomologous pair of chromosomesin diploid parent cellChromosomesreplicateHomologous pair of replicated chromosomesSisterchromatidsDipl

11、oid cell withreplicated chromosomesInterphaseHomologous pair of chromosomesin diploid parent cellChromosomesreplicateHomologous pair of replicated chromosomesSisterchromatidsDiploid cell withreplicated chromosomesMeiosis IHomologouschromosomesseparate 1Haploid cells withreplicated chromosomes Interp

12、haseHomologous pair of chromosomesin diploid parent cellChromosomesreplicateHomologous pair of replicated chromosomesSisterchromatidsDiploid cell withreplicated chromosomesMeiosis IHomologouschromosomesseparate 1Haploid cells withreplicated chromosomes Meiosis II2Sister chromatidsseparate Haploid ce

13、lls with unreplicated chromosomes ChromosomeSister Chromatids22110420reductionThe Stages of MeiosisMeiosis I: - homologous chromosomes separate - results in two haploid daughter cells with replicated chromosomes - also celled the reductional divisionMeiosis II: - sister chromatids separate - results

14、 in four haploid daughter cells with unreplicated chromosomes - also called the equational divisionEssential PropertiesProphase I of Meiosis synapsis: crossing over: chiasma (chiasmata): Prophase I of Meiosis synapsis: The pairing and physical connection of duplicated homologous chromosomes. crossin

15、g over: The reciprocal exchange of genetic material between nonsister chromatids. chiasma (chiasmata): The X-shaped, microscopically visible region where crossing over has occurred between homologous nonsister chromatids.tetradA Comparison of Mitosis and MeiosisRG-C13-Q19MITOSISMEIOSISMEIOSIS IProph

16、ase IChiasmaChromosomereplicationHomologouschromosomepairChromosomereplication2n = 6Parent cellProphaseReplicated chromosomeMetaphaseMetaphase IProphase ITelophase IHaploid n = 3Daughter cells ofmeiosis IMEIOSIS IIDaughter cells of meiosis IInnnn2n2nDaughter cellsof mitosisAnaphaseTelophaseSUMMARYMe

17、iosisMitosisPropertyDNAreplicationNumber ofdivisionsOccurs during interphase beforemitosis beginsOne, including prophase, metaphase,anaphase, and telophaseSynapsis ofhomologouschromosomesDoes not occurNumber ofdaughter cellsand geneticcompositionTwo, each diploid (2n) and geneticallyidentical to the

18、 parent cellRole in theanimal bodyEnables multicellular adult to arise fromzygote; produces cells for growth, repair,and, in some species, asexual reproductionOccurs 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