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时间:2019-11-14
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1、LessonOneInsidetheLivingCell:StructureandFunctionofInternalCellPartsCytoplasm:TheDynamic,MobileFactory细胞质:动力工厂Mostofthepropertiesweassociatewithlifearepropertiesofthecytoplasm.Muchofthemassofacellconsistsofthissemifluidsubstance,whichisboundedontheoutsidebytheplasmamembrane・Organellesaresuspe
2、ndedwithinit,supportedbythefilamentousnetworkofthecytoskeleton.Dissolvedinthecytoplasmicfluidarenutrients,ions,solubleproteins,andothermaterialsneededforcellfunctioning・生命的人部分特征表现在细胞质的特征上。细胞质人部分由半流体物质组成,并由细胞膜(原生质膜)包被。细胞器悬浮在其中,并由丝状的细胞骨架支撑。细胞质屮溶解了人量的营养物质,离子,可溶蛋白以及维持细胞生理需求的其它物质。TheNucleus:Inform
3、ationCentral(细胞核:信息屮心)Theeukaryoticcellnucleusisthelargestorganelleandhousesthegeneticmaterial(DNA)onchromosomes.(Inprokaryotesthehereditarymaterialisfoundinthenucleoid.)Thenucleusalsocontainsoneortwoorganelles-thenucleoli-thatplayaroleincelldivision.Apore-perforatedsaccalledthenuclearenvelop
4、eseparatesthenucleusanditscontentsfromthecytoplasm.Smallmoleculescanpassthroughthenuclearenvelope,butlargermoleculessuchasmRNAandribosomesmustenterandexitviathepores.真核细胞的细胞核是最人的细胞器,细胞核对染色体组有保护作川(原核细胞的遗传物质存在于拟核屮)。细胞核含有一或二个核仁,核仁促进细胞分裂。核膜贯穿许多小孔,小分子可以自由通过核膜,而象mRNA和核糖体等大分子必须通过核孔运输。Organelles:Spec
5、ializedWorkUnits(细胞器:特殊的功能单位)Alleukaryoticcellscontainmostofthevariouskindsoforganelles,andeachorganelleperformsaspecializedfunctioninthecell.Organellesdescribedinthissectionincluderibosomes,theendoplasmicreticulum,theGolgicomplex,vacuoles,lysosomes,mitochondria,andtheplastidsofplantcells.所有的
6、真核细胞都含有多种细胞器,每个细胞器都有其特定功能。本节主要介绍核糖体,内质网,高尔基体系,液泡,溶酶体,线粒体和植物细胞中的质体。Thenumberofribosomeswithinacellmayrangefromafewhundredtomanythousands・Thisquantityreflectsthefactthat,ribosomesarethesitesatwhichaminoacidsareassembledintoproteinsforexportorforuseincellprocesses.Acompleteribosomeiscomposedofon
7、elargerandonesmallersubunit・DuringproteinsynthesisthetwosubunitsmovealongastrandofniRNA,ureadingnthegeneticsequencecodedinitandtranslatingthatsequenceintoprotein.SeveralribosomesmaybecomeattachedtoasinglemRNAstrand;suchacombinationiscalledapo
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