1、2.1 2.1 细胞的结构细胞的结构细胞的结构细胞的结构(Structure of Cells)(Structure of Cells)All start out life All start out life with:with:细胞膜细胞膜(Plasma(Plasma membrane,encircling membrane,encircling a region where DNA a region where DNA is stored)is stored)细胞质细胞质(Cytoplasm)(Cytoplasm)Two types:Two types:原核原核(Prokaryotic)
2、(Prokaryotic)真核真核(Eukaryotic)(Eukaryotic)真核细胞真核细胞 (Eukaryotic Cells)(Eukaryotic Cells)具细胞核和其他细胞器具细胞核和其他细胞器(Have a(Have a nucleus and other organelles)nucleus and other organelles)真核生物真核生物(Eukaryotic organisms)(Eukaryotic organisms)植物植物(Plants)(Plants)动物动物(Animals)(Animals)原生生物原生生物(Protistans)(Protis
3、tans)：所有不是动物、：所有不是动物、植物或真菌的真核生物，包括纤毛虫、鞭植物或真菌的真核生物，包括纤毛虫、鞭毛虫等（草履虫、锥虫、疟原虫）毛虫等（草履虫、锥虫、疟原虫）真菌真菌(Fungi)(Fungi)锥虫、披发虫等；纤毛虫纲包括喇叭虫、草履虫、四膜虫、钟形虫、栉毛虫等；肉足纲包括放射虫、衣壳虫、沙壳虫、太阳虫、变形虫、有孔虫等；孢子虫纲就一种典型的，是疟原虫。动物细胞动物细胞(Animal Cells)(Animal Cells)质膜质膜Plasma membranePlasma membrane 细胞核细胞核NucleusNucleus 核糖体核糖体RibosomesRibosom
4、es 内质网内质网Endoplasmic Endoplasmic reticulumreticulum 高尔基体高尔基体Golgi bodyGolgi body 小泡小泡VesiclesVesicles 线粒体线粒体MitochondriaMitochondria 溶酶体溶酶体LysosomeLysosome 细胞骨架细胞骨架CytoskeletonCytoskeleton中心体中心体 Centrosome植物细胞植物细胞(Plant Cells)细胞壁细胞壁Cell wallCell wall 中央液泡中央液泡Central Central vacuolevacuole 叶绿体叶绿体Chlo
5、roplastChloroplast 质膜质膜Plasma membranePlasma membrane 细胞核细胞核NucleusNucleus 核糖体核糖体RibosomesRibosomes 内质网内质网Endoplasmic Endoplasmic reticulumreticulum 高尔基体高尔基体Golgi bodyGolgi body 小泡小泡VesiclesVesicles 线粒体线粒体MitochondriaMitochondria 溶酶体溶酶体LysosomeLysosome 细胞骨架细胞骨架CytoskeletonCytoskeleton细胞核细胞核(Nucleus)
6、(Nucleus)G0G0和和G1G1期染色体期染色体:染色质染色质(Chromosomes(Chromosomes at G1 phase:Chromatin)at G1 phase:Chromatin)2 nm2 nm30 nm30 nmCoding(Coding(blueblue)and)andnon-coding strands non-coding strands(greygrey)of DNA)of DNAG0G0和和G1G1期细胞中染期细胞中染色体通常存在的状色体通常存在的状态态(The(The“usualusual”state of state of chromosomes i
7、n chromosomes in G0 and G1 cells)G0 and G1 cells)7 7S-G2S-G2期染色体期染色体:染色质染色质(Chromosomes at(Chromosomes at S-G2 phase:Chromatin)S-G2 phase:Chromatin)“OldOld”coding strand coding strand“NewNew”coding strand coding strandSpecial DNA binding proteins e.g.cohesinsSpecial DNA binding proteins e.g.cohesins
8、8 8G2G2期细胞中染色体通期细胞中染色体通常存在的状态常存在的状态(The(The“usualusual”state stateof chromosomes inof chromosomes inG2 cells(G2 cells(after DNA after DNA replicationreplication)两个两个G1期染色质的并排排列，之间有期染色质的并排排列，之间有cohesins蛋白连接蛋白连接前期染色体前期染色体(Chromosomes at prophase)(Chromosomes at prophase)“Old”coding strand“New”coding s
9、trandMitotic Chromosome9 9When cells entry mitosis:Chromatin condense together into a mitotic chromosome10The mechanism of chromosome condensation is not completely understood but notePPPhosphorylation of histones&proteins in condensin complexCondensincomplexDNA package and chromosome condensation w
10、ith cell cycle progression from G2 to metaphase Karyotype 46,XY中期染色体中期染色体(Chromosomes at Metaphase)5 um着丝粒着丝粒 CentromeresCentromeres the largest constriction of the chromosome.100,000s of 171 base pair repeat,called alpha satellite sequencesCentromere associated proteins are bound:KinetochoreSite of
11、 attachment of spindle fibersCentromere and Kinetochore端粒端粒 TelomeresAt the tips of chromosomes:Protect Many repeats of the sequence TTAGGGSubtelomeres have more varied short repeats人类全着丝粒探针人类全着丝粒探针（pan-centromeric，Green)和全端粒探针和全端粒探针（pan-telomeric，Red)荧光原位杂交检测染色体的完整性荧光原位杂交检测染色体的完整性Human N-Tert1 cell
12、s have intact chromosomes detected by FISH using telomeric and centromeric probesQinghua ShiunpublishedTell me what I am?染色体是一个物种区分于其他物种的最基本遗传特征染色体是一个物种区分于其他物种的最基本遗传特征不同物种染色体数目不同不同物种染色体数目不同物种物种SpeciesSpecies 二倍体二倍体#单倍体单倍体#牛牛CattleCattle 60 603030猪猪SwineSwine 38 381919羊羊SheepSheep 54 542727马马HorseHor
13、se 64 643232人人HumanHuman 46 462323鸡鸡ChickenChicken 78 783939山羊山羊GoatGoat 60 603030驴驴DonkeyDonkey 62 623131染色体最少的生物：一种蚂蚁（染色体最少的生物：一种蚂蚁（M.pilosula），单倍体细胞仅），单倍体细胞仅1条染色体条染色体染色体最多的生物：？染色体最多的生物：？染色体染色体 The ChromosomesThe Chromosomes 染色体在体细胞中成对出现染色体在体细胞中成对出现 Chromosomes Chromosomes occurs in pairs in every
14、 somatic cell occurs in pairs in every somatic cell except in the sperm and ovum.except in the sperm and ovum.一个物种的绝大多数（全部）体细胞，其染一个物种的绝大多数（全部）体细胞，其染色体数目相同色体数目相同Chromosomes numbers are Chromosomes numbers are the same in vast majority(every)the same in vast majority(every)somatic cell for each specie
15、s.somatic cell for each species.染色体染色体 The Chromosomes 在二倍体细胞中含在二倍体细胞中含2 2条性染色体条性染色体 There are 2 There are 2 sex sex chromosomeschromosomes included in the diploid number of included in the diploid number of the chromosomes.the chromosomes.除性染色体以外的染色体统称为常染色体除性染色体以外的染色体统称为常染色体 All of All of the other
16、 chromosomes are referred to as the other chromosomes are referred to as autosomesautosomes.雌性哺乳类的雌性哺乳类的2 2条性染色体相同条性染色体相同 In mammals if the In mammals if the sex chromosomes are alike,XX it results in a sex chromosomes are alike,XX it results in a female.female.雄性哺乳类的雄性哺乳类的2 2条性染色体不同条性染色体不同 If the s
17、ex If the sex chromosomes are different,XY it results in a chromosomes are different,XY it results in a male.(male.(例外：毛冠鹿例外：毛冠鹿)染色体传递：细胞分裂染色体传递：细胞分裂Chromosome transmitting:Cell DivisionChromosome transmitting:Cell Division Meiosis Meiosis 减数分裂减数分裂Is the form of cell division which results Is the fo
18、rm of cell division which results reduce the chromosome number from the reduce the chromosome number from the diploid#to the haploid#.diploid#to the haploid#.Occurs only in the sex cells,generate Occurs only in the sex cells,generate sperm and egg.sperm and egg.Mitosis Mitosis 有丝分裂有丝分裂Is the form of
19、 cell division which results Is the form of cell division which results in the formation of identical daughter cells,in the formation of identical daughter cells,keeps the chromosome number constant.keeps the chromosome number constant.Tissue growth and repair.Tissue growth and repair.Occurs through
20、out the body except in the Occurs throughout the body except in the sex cells.sex cells.正常有丝分裂正常有丝分裂AbscissionShi&King,Nature 437:1038-1042,2005绿色荧光蛋白绿色荧光蛋白（Green fluorescence protein,GFP）-组组蛋白蛋白H2B融合基因，融合基因，转入细胞中，使其转入细胞中，使其表达表达G2ProphaseMetaphaseAnaphaseTelophaseG1SG2 CheckpointSpindle checkpointA
21、mechanism responds to chromosome missegregation?细胞周期示意图细胞周期示意图 Cell Cycle ProgressionG1 CheckpointShi,unpublished贝班贝班细胞周期细胞周期 The Cell Cycle 是一个细胞从其形成到其分裂为是一个细胞从其形成到其分裂为2 2个细胞的一系列个细胞的一系列按序发生的事件按序发生的事件 The The cell cyclecell cycle is an is an orderly sequence of events that occurs orderly sequence of
22、 events that occurs from the time when a cell is first formed from the time when a cell is first formed until it divides into two new cells.until it divides into two new cells.Most of the cell cycle is spent in Most of the cell cycle is spent in interphaseinterphase（G1G1，S S 和和G2G2.Following interph
23、ase,the Following interphase,the mitotic stagemitotic stage of of cell division occurs.cell division occurs.Division(Division(前、中、后、前、中、后、末期和细胞质分裂末期和细胞质分裂G2Early Prophase*Chromosomes condense*Nuclear envelope disappears*Centrioles move to opposite sides of the cellLate ProphaseSpindle forms and atta
24、ches to kinetochores on the chromosomesMetaphase*Chromosomes lined up on equator of spindle*Centrioles at opposite ends of cellAnaphase*Centromeres divide:each 2-chromatid chromosome becomes two 1-chromatid chromosomes*Chromosomes pulled to opposite poles by the spindleTelophase*Chromosomes deconden
25、se*Nuclear envelope reappears*Cytoplasm divided into 2 cellsCytokinesis in Animal Cells In animal cells,a cleavage furrow begins at the end of anaphase.A band of actin and myosin filaments,called the contractile ring,slowly forms a constriction between the two daughter cells.A narrow bridge between
26、the two cells is apparent during telophase,then the contractile ring completes the division.Cytokinesis in animal cellsMitosis in Detail During mitosis,the spindle distributes the chromosomes to each daughter cell.The spindle contains fibers made of microtubules that disassemble and assemble.Centros
27、omes,that duplicate and separate during interphase,organize the spindle.Centrosomes contain centrioles and asters.Mitosis has four phases:prophase,metaphase,anaphase,and telophase.Mitosis:Maintaining Chromosome NumberMeiosis:Halving chromosome numberMeiosis:Two Divisions Two consecutive nuclear divi
28、sions Meiosis IMeiosis II DNA is NOT duplicated between divisions Four haploid nuclei are formed Stages of MeiosisMeiosis I Prophase I Metaphase I Anaphase I Telophase IMeiosis II Prophase II Metaphase II Anaphase II Telophase IIChromosome behavior in meiosis I prophase联合复合体联合复合体（SC）SC:SC:位于两条同源染色体之
29、间，沿纵轴方向延伸；位于两条同源染色体之间，沿纵轴方向延伸；两侧为侧生组分，宽约两侧为侧生组分，宽约20-40nm20-40nm；侧生组分间为中间区，宽约侧生组分间为中间区，宽约100nm100nm；中间区的中央为中央组分，宽约中间区的中央为中央组分，宽约30nm30nm；侧生组分和中央组分之间有横向排列的纤维，大致成直角相连，侧生组分和中央组分之间有横向排列的纤维，大致成直角相连，称称L-CL-C纤细；纤细；SCSC主要由碱性蛋白组成主要由碱性蛋白组成ASYCP3:示联会复合体侧轴；示联会复合体侧轴；MLH1：示重组位点；：示重组位点；CREST：示着丝粒：示着丝粒人人精母细胞减数分裂精母细
30、胞减数分裂I前期前期Meiosis I-StagesProphase IMetaphase I Anaphase ITelophase ICrossing overRandom alignment of chromosomes at metaphase IHomologues separateMeiosis II-StagesProphase IIMetaphase II Anaphase II Telophase IISister chromatids separate精子发生精子发生 SpermatogenesisGrowthMitosis I,Cytoplasmic divisionMe
31、iosis II,Cytoplasmic divisionspermatids(haploid)secondary spermatocytes(haploid)primary spermatocyte(diploid)spermato-gonium(diploid male reproductive cell)卵子发生卵子发生OogenesisGrowthMeiosis I,Cytoplasmic divisionMeiosis II,Cytoplasmic division卵子卵子(n)ovum(haploid)初级卵母细胞初级卵母细胞(2n)primary oocyte(diploid)卵
32、原细胞卵原细胞(2n)oogonium(diploid reproductive cell)次级卵母细胞次级卵母细胞(n)secondary oocyte(haploid)第一极体第一极体(n)first polar body(haploid)三个极体三个极体(n)3 polar bodies(haploid)人类生命周期人类生命周期 Life cycle of humans受精受精 FertilizationFertilization 雌雄配子结合、细胞核融合雌雄配子结合、细胞核融合 Male and female Male and female gametes unite and nucl
33、ei fusegametes unite and nuclei fuse 两个单倍体的配子融合形成二倍体的合子两个单倍体的配子融合形成二倍体的合子 Fusion Fusion of two haploid nuclei produces diploid of two haploid nuclei produces diploid nucleus in the zygotenucleus in the zygote 配子融合是随机的配子融合是随机的 That two gametes unite is That two gametes unite is randomrandom增加了子代的变异增加
34、了子代的变异 Adds to variation among Adds to variation among offspringoffspring导致子代变异的因素导致子代变异的因素 Factors Contributing to Factors Contributing to Variation Among OffspringVariation Among Offspring 前期前期I I同源染色体间的交换同源染色体间的交换 （Crossing over Crossing over during prophase Iduring prophase I 中期中期I I染色体在赤道板上的自由排
35、列染色体在赤道板上的自由排列 （Random Random alignment of chromosomes at metaphase Ialignment of chromosomes at metaphase I 配子的自由组合配子的自由组合 （Random combination of Random combination of gametes at fertilizationgametes at fertilizationMITOSIS Occurs in most types of eukaryotic cells.Slide 16MitosisMeiosis IMeiosis II
36、Figure 10.10Page 172-173MEIOSISOccurs in formation of gametes in eukaryotic cells 有有丝丝分分裂裂和和减减数数分分裂裂比比较较MITOSIS No pairing of Homologous chromosomesSlide 16MitosisMeiosis IMeiosis IIFigure 10.10Page 172-173MEIOSISHomologous chromosomes pair&synapsis;crossing over may occur有有丝丝分分裂裂和和减减数数分分裂裂比比较较MITOS
37、IS Chromosome number is maintained.Slide 16MitosisMeiosis IMeiosis IIFigure 10.10Page 172-173MEIOSISChromosome number is reduced from diploidy to haploidy.有有丝丝分分裂裂和和减减数数分分裂裂比比较较MITOSIS One divisionSlide 16MitosisMeiosis IMeiosis IIFigure 10.10Page 172-173MEIOSISTwo divisions有有丝丝分分裂裂和和减减数数分分裂裂比比较较MIT
38、OSIS Two daughter cells are produced.Slide 16MitosisMeiosis IMeiosis IIFigure 10.10Page 172-173MEIOSISFour daughter cells are produced.有有丝丝分分裂裂和和减减数数分分裂裂比比较较MITOSIS Daughter cells are identical to each other and to parent cellSlide 16MitosisMeiosis IMeiosis IIFigure 10.10Page 172-173MEIOSISDaughter
39、cells contain varying combinations of chromosomes有有丝丝分分裂裂和和减减数数分分裂裂比比较较Mitosis Functions Asexual reproduction Growth,repair Occurs in somatic cells Produces clones Mitosis&Meiosis ComparedMeiosis Function Sexual reproduction Occurs in germ cells Produces variable offspring有有丝丝分分裂裂和和减减数数分分裂裂比比较较前期前期
40、(Prophase vs.Prophase I)(Prophase vs.Prophase I)有丝分裂前期有丝分裂前期 (Prophase,Mitosis)(Prophase,Mitosis)同源染色体互不影响同源染色体互不影响 (Homologous pairs do(Homologous pairs do not interact with each other.)not interact with each other.)减数分裂前期减数分裂前期I I(Prophase I,Meiosis)(Prophase I,Meiosis)同源染色体配对、联会、遗传物质交换同源染色体配对、联会、
41、遗传物质交换（Homologous pairs become zippered Homologous pairs become zippered together and crossing over occurs.)together and crossing over occurs.)有有丝丝分分裂裂和和减减数数分分裂裂比比较较 分裂后期分裂后期 减数分裂后期减数分裂后期I I(Anaphase I,Meiosis)(Anaphase I,Meiosis)同源染色体分开同源染色体分开(Homologous chromosomes are(Homologous chromosomes are s
42、eparated from each other.)separated from each other.)有丝分裂后期有丝分裂后期/减数分裂后期减数分裂后期II II(Anaphase/Anaphase II,Mitosis/Meiosis)(Anaphase/Anaphase II,Mitosis/Meiosis)姐妹染色单体分开姐妹染色单体分开 (Sister chromatids of a(Sister chromatids of a chromosome are separated from each other)chromosome are separated from each o
43、ther)有有丝丝分分裂裂和和减减数数分分裂裂比比较较分裂结果分裂结果(Results of Mitosis(Results of Mitosis and Meiosis)and Meiosis)有丝分裂有丝分裂 (Mitosis)(Mitosis)2 2个二倍体细胞个二倍体细胞 (Two diploid cells produced)(Two diploid cells produced)2 2个子细胞均与亲代细胞相同个子细胞均与亲代细胞相同(Each identical to (Each identical to parent)parent)减数分裂减数分裂 (Meiosis)(Meios
44、is)4 4个单倍体细胞个单倍体细胞 (Four haploid cells produced)(Four haploid cells produced)4 4个子细胞互不相同个子细胞互不相同,且有别于亲代细胞且有别于亲代细胞 (Differ from(Differ from parent and one another)parent and one another)有有丝丝分分裂裂和和减减数数分分裂裂比比较较生命的细胞理论（生命的细胞理论（1 1）1)1)每种生物都是由每种生物都是由1 1个或多个细胞组成的个或多个细胞组成的 (Every(Every organism is consiste
45、d of one or more cells)organism is consisted of one or more cells)2)2)细胞是生命的最小单位细胞是生命的最小单位(Cell is smallest unit of Cell is smallest unit of life)life)3)3)生命的延续是以单个细胞的生长和分裂为基础的生命的延续是以单个细胞的生长和分裂为基础的(Continuity of life arises from growth and(Continuity of life arises from growth and division of single
46、 cells)division of single cells)4 4可独自生存或具此潜力可独自生存或具此潜力 Can survive on its Can survive on its own or has potential to do soown or has potential to do so5 5可进行高度有序的代谢可进行高度有序的代谢 Is highly organized Is highly organized for metabolismfor metabolism6 6可感受并对环境的变化作出反应可感受并对环境的变化作出反应 Senses and Senses and responds to environmentresponds to environment7 7具有增殖的潜力具有增殖的潜力 Has potential to reproduceHas potential to reproduce生命的细胞理论（生命的细胞理论（2 2）
