细胞是生命活动的基本单位.pdf

细胞是生命活动的基本单位1.结构的基本单位2.功能的基本单位新陈代谢生长发育繁殖3.在生命起源中的意义病毒结构核酸(RNADNA)蛋白质 类病毒：RNA肮病毒：感染性蛋白质ruiHmfAf售Figure 1.22 Virus diversity.The structures of(a)an adenovirus,(b)a human immunodeficiency vims(HIV),and(c)a T-evcn bacteriophage.(Note Huy viruses are not drawn to the same scale.)细胞、病毒在起源与进化中的关系?生物大分子-病毒-细胞 病毒 生物大分（A细胞生物大分子一细胞一病毒(a)Prokaryotic cellNucleoidPenplasmic space and cell wallOuter membrane Inner(plasma)Nucleoid 0.5membrane J(b)Eukaryotic cellEndoplasmic reticulum FIGURE 1-7 Comparison of the structure of prokaryotic and eukaryotic cells.(al Drawing of a typical granvnegative prokaryotic bactenal)cell in the process of dividing and electron micrograph of a thin section of E.coh,a common niesunal bacterium Note the penplasmic space between the inner and outer membranes,and the cell wall adiacent to the inner membrane(b)Drawing of a eukaryotic cell and electron micrograph of a plasma cell,a type of wh.te blood cell that secretes antibodies.Only a single membrane(the plasma membrane)surrounds tne ceil,but the interior contains many memorane-hmited compartments known as organelles,which are described in m2的同化：Chloroplast(a)A chloroplastInner membraneOuter membraneThylakoid lumenCytosolStromaSYNTHESISSYNTHESISStarch jSucrose|TRANSPORT andPROTON PUMPINGTnose phosphatesTriose phosphaies(b)Localization ol photosynihesis within the chloroplastStromaPhotosystem IIThylakoid lumen线粒体是怎样进行呼吸作用的?有机物脱竣、脱氢：电子传递链及氧化磷酸化:化学渗透假说：outer mitochondrial membranepyruvate fatty acidsFOOD MOLECULES FROM CYTOSOL细胞是如何连接成组织的？封闭连接：相邻细胞质膜密切连接，防 止物质从细胞间隙通过。锚定连接：通过细胞骨架系统将相邻细 胞及细胞外基质连接起来，稳固组织。通讯连接：相邻细胞质膜蛋白形成相对 应孔道，物质及信息可以通过。(b)Tight junction(c)Gap junctionExtracellular matrixDesmosome/Hemidesmosome/FocalAdhesion beltcontact Adherens J junctions(a)Adhesive junctionsTWATCTiOH 11t0cM 131111Mgetttatele 2(1n/cQnai pgmrwF gaE luicoor(e)C3fF、？5 juncocvi UxxKa OftiMOn et pwm ffwmiww mtmyintgrwzctqngr g缺go，f*W(a)0.1 pmLipid bilayer(iIntermediate filamentDesmoplakinCytoplasmic plaque(b)CM i InterceihJtar space Ceh 2Figure 7.27 The structure of a desmosome.(a)Electron micrograph of a desmosome from newt epidermis,(b)Schematic model of the molecular architecture of a desmosome.(a:From Douglas E.Kelly,J.Cell Biol.28:51,1966;by copyright permission of the Rockefeller University Press.)(b)Ftgure 11-15 Desmosome Structure(a)An m cr叫”of a desmotome joining two celifi in the ihn of a newt(TEM)他)A sdwtnatic diagram at a desmosow The distance tetween：ell5 m the destnowns region t5 25-35 nm about that for a nonjiMcnon tegion Ths dssniosonti com between the two memDranes fHJed 帅伯 gfycounjtei-iallied dsxinocohmi and desmoglcmi The plsque or of the membrane cnntans proteins called desmop a arid is linked to the cytoskeleton by tonofiiamems.ml&rmedtate filaments that consist of keratin,desmi depending on the cell typePostsynapttc neuronPostsynapnc membrane(a)An electrical synapse(b)Gap junctionsFigure 9-20 An Electrical Syn叩se.(a)In electrical synapses,the presynaptic and postsynaptic neurons are coupled by gap junctions Gap junctions allow small molecules and ions to pass freely from the cytosol of one cell to the next Therefore,when an action potential arrives at the presynaptic side of an electrical synapse,die depulanzalion spreadsChannel formed by pores in each membranepassively,due to the Haw of positively charged ions,across the gap juncbon(b)Itie gap junction is composed of sets of channels.Each channel is made.up of six protein subunits called cowiexins The entire set of six subunns togetlier is called a connexon.Tw connexonsr one in the presynantic membrane and une in the pusuyndptic rnembrane,inake up a gap juncrm细胞间是如何进行信息传递的?1.细胞间形成通讯连接。2.细胞间接触性依赖通讯。3.细胞间分泌化学信号。/内分泌旁分泌自分泌细胞是如何接受外界信号的?细胞内受体 细胞表面受体:Z离子通道受体与酶相连的受体整联蛋白G蛋白：与GTP结合的蛋白。第二信使。(A)ion-channel-linked receptor(B)G-PROTEIN-LINKED RECEPTORsignal moleculeGPLR：种类繁多，真核 细胞普遍表达（7次跨膜）G proteinenzymeactivatedG proteinenzyme(0 ENZYME-LINKED RECEPTORS信号分子包括：感觉信号（光、嗅、声等；激素、神经递质等）GPLR的效应器：AC、PLC、PLA2、GRK（GPLR 激酶）、PDE、PI3K、离子通道等inhibitoryprotein complextranscription-x activating/domainDNA-binding domainsteroidhormone-DNAbindin(wy(A)hormone-binding site DNA-binding1/domain)N-Cj cortisol receptor喙iZ一 estrogen receptorhinge region N cprogesterone receptor_/N_ J vitamin D receptorg site exposed retinoic acid receptor（A）细胞内受体蛋白作用模型；（B）几种胞内受体蛋白超家族成员2 Binding of GRB2 and j Sos couples receptor to inactive Ras%、；p)pActive RasGRB2GDpy|3 Sos promotes dissociation of GDP from Ras;GTPGTP f binds and Sos dissociates from active RasVSignalingEGF receptorf J J I，JK 巧励聊JI即邮脚侬则妙川陂娜则峭迎喇 Autophosphorylation of tyrosinesOUTSIDE OF CELLDAG/CYTOSOL Ugand(EGF)binding and receptor aggregationPLS Binding of cytosolic proteins with、SH2 domainsActivated PLCy stimulates lnsP3-DAG pathway藐/慝产0r(5)Aclivated I GRB2-Sos stimulates Ras I pathway _iMAPKFigure 10-17 Signal Transduction Through Receptor Tyrosine Kinases.Upon hgand binding,receptor tyrosine kinases,such as 由st shown here for the epidermal growth factor(EGF).aggregate andI undergo autophosphorylalion,Once a receptor is phosphorylated at tirosine residues on the cytosolic tail.proteins with SH2 domains such as phospholipase C(PLC)and GRB2 bind to the receptor.The finding of phospholipase C results in 心 activation and the cleavage ofPIP?into lnsP3 and DAG.The binding of GRB2 causes the activation of Sos.a guanine-nudeotide release protein to which it is bound Sos then causes the activation of the Ras protein by helping it release GDP and acquire GTP Activated Ras initiates a cascade of events that ultimately results in the formation of AP-1,a uanscription factor in the nucleus that stimulates the expression of genes needed for cell growth15.34 Sigzln trARRmiilrd Fmm tHe recentnt ditUfMt pathwwrr tKif,ht，phodyhnuWiioLB into IPj and PAG both second mcMcngrm pgv 88).Hath of thtx cnxymo tarui it the twid uf tluHr uwn jm小e”s nd thu bmduifi c*Utrd tnoitnlw(Figurr I 1口)Figure 155 5 eampl of cmfvUlh a(or 7杯、“鹏 fwthBey”IM AMP Ari*tn rd q”“mrM4 if the cAMP3cpvidcm Una FKA.ti bk)d d UMMiuxUcrt W 3.from Rm io R“Hrh ii.WX”MthfAtiDn of the MAP kitMoe CMOidtf.Signals transmitted from the EGF receptor can along several distinct pathways.An example of between two major signaling pathways染色体复制的三个关键序列自主复制DNA序列:着丝粒DNA序列：端粒DNA序列：DNA的复制只能在3,末端添加核甘酸并必须有RNA引物。INTERPHASErepl cation buboleMITOSISINTERPHASEportion of mitotic spindleduplicated chromosomes in separate cells伟)Figure 1X17 Telomere*,(a)In Miu hridimtion of a DNA probe cnntAtning the sequence TTAGGG.whkh local。iz to the tekxncrv*o(human chrtmcomeiL fb)Denum-rtrahon ihut certain protein*bind specifically U)Iriomcrk DNA.These chromowmc were prepared from a nuMtrtic nudw RNA Mairted with propldium kxiide.伍 From J.Mtync.hi RR Warner,Chromcmomew：A Synthesis.Copyri脚 C J993.Rnnttat fry 川 1 DfWilchmflnc.4,曲珈cry of/而”Wiley&Sow,Inc.;b：frvm Franz Klein,d U,I Cell Bidl 17:940,1992,amrtefy of Sumti M Gtwrr;by copyright prrwmMn vf iht Roduffltcr Untwriti/Pmt.l关于细胞周期细胞周期:分裂间期：Gi期、S期、G2期嬲期(M)：B纺锤周期中细胞静止期细胞(Go期)终末分化细胞Interphase如何理解细胞的分化？细胞分化：遗传上同质的细胞逐渐变为形态、结构、功能上不同的细胞。关键是特异性蛋白的合成。实质是基因选择性表达。管家基因：奢侈基因：dead flattened cells packed with keratinEPIDERMIS epithelium)DERMIS(connective tissue)CELLS ARE BORNbasal lamina dividing basal cellCELLS ARE SHED转分化与再生一种类型分化的细胞转变成另一种类型的分化细胞现象 称转分化(transdifferentiation)。转分化经历去分化(dedifferentiation)和再分化的过程。生物界普遍存在再生现象(regeneration),再生是指生物 体缺失部分后重建过程，广义的再生可包括分子水平、细 胞水平、组织与器官水平及整体水平的再生。不同的细胞有机体，其再生能力有明显的差异。致癌因素多种理化因子致癌DNA肿瘤病毒与RNA肿瘤病毒致癌Rousl911年发现肿瘤病毒，1966年87岁获诺贝尔奖癌基因，原癌基因，抑癌基因癌症产生是基因突变积累和自然选择的结果癌症主要是体细胞突变产生的遗传病，涉及 到两大类与细胞增殖相关的基因的突变。促进细胞增殖相关基因突变：原癌基因(proto-oncogene)突变形成癌基因(oncogene)抑制细胞增殖相关基因突变：肿瘤抑制基因(tumor-suppressor gene)细胞癌变是基因突变累积和自然选择的 结果，所以患者多为年长者。原癌基因与肿瘤抑制基因产物协调作用，避免细胞癌变影响细胞分化的因素卵细胞质的不均一性细胞间的相互作用与位置效应细胞记忆与决定环境对性别决定的影响染色质变化与基因重排(A)connective tissueforebrain(neural tube epithelium)lumen of optic-vesicle ectoderm of headoptic cup(C)pigment epithelium of retina neural epithelium of retinadeveloping cornealens vesicleDrosophila II.Homeotic Selector Genes and the Patterning of Body Partsmetamorphosispart of disc grafted to another larvaadult structures differentiate from imaginal disc cellsimaginal disc cells proliferate in adult fly and can be serially transplanted from one host adult to anothersame adult structures form as from original imaginal disc cells细胞衰老，Hay flick界限细胞，至少是培养的二倍体细胞，不是不死的，而 是有一定的寿命；它们的增殖能力不是无限的，而是有一定的界限，这就是Hayflick界限nn二倍体细胞的衰老是由细胞本身决定的决定细胞衰老的因素在细胞内部，而不是外部的 环境是细胞核而不是细胞质决定了细胞衰老噌瞥胃的概念及其生物学意义概念：细胞凋亡是一个主动的由基因决定的自 动结束生命的过程，所以也常常被称为细胞 编程死亡。凋亡细胞将被吞噬细胞吞噬。生物学意义：细胞凋亡对于多细胞生物个体发 育的正常进行，自稳平衡的保持以及抵御外界各 种因素的干扰方面都起着非常关键的作用细胞凋亡与坏死(necrosis)二者的主要区别是，细胞凋亡过程中，细胞质膜反折,包裹断裂的染色质片段或细胞器，然后逐渐分离，形 成众多的凋亡小体(apoptotic bodies),凋亡小体则为 邻近的细胞所吞噬。整个过程中，细胞质膜的整合性 保持良好，死亡细胞的内容物不会逸散到胞外环境中 去，因而不引发炎症反应。相反，在细胞坏死时，细 胞质膜发生渗漏，细胞内容物，包括膨大和破碎的细 胞器以及染色质片段，释放到胞外，导致炎症反应1 mm(A)(B)Mild convolutionChromatin compaction and segregationCondensation of cytoplasmNuclear fragmentationBlobbingCell fragmentationApoptotic bodyPhagocytosis 父*(a)FIGURE 23-45(a)Ultrastructural features of cell death by apoptosis,(a)Schematic drawings Illustrating the progression of morphologic changes observed In apoptotic Early in apoptosis dense chromosome condensation occurs along the nuclear periphery.The cell body also shrinks although most organelles remain Intact Later both the nucleus and cytoplasm fragment,forming apoptotic bod les.These are phagocytosed by surrounding cells,Part(a)adapted from J.Kuby.1997,Immunology,3d ed.W.H Freeman&Co,p.53 Phagocytic