新人教版英语选修八第二单元新授课课件.ppt

cloning,Watchthevideo:TheCloningTechnologyofChina,克隆,是Clone的译音,意为生物体通过细胞进行的无性繁殖形成的基因型完全相同的后代个体组成的种群,简称为“无性繁殖”。“克隆”一词于1903年被引入园艺学,以后逐渐应用于植物学、动物学和医学等方面。克隆与无性繁殖是不同的。无性繁殖是指不经过雌雄两性生殖细胞的结合、只由一个生物体产生后代的生殖方式,常见的有孢子生殖、出芽生殖和分裂生殖。由植物的根、茎、叶等经过压条或嫁接等方式产生新个体也叫无性繁殖。绵羊、猴子和牛等动物没有人工操作是不能进行无性繁殖的。科学家把人工遗传操作动物繁殖的过程叫克隆,这生物技术叫克隆技术。,克隆的基本过程是先将含有遗传物质的供体细胞的核移植到去除了细胞核的卵细胞中,利用微电流刺激等使两者融合为一体,然后促使这一新细胞分裂繁殖发育成胚胎,当胚胎发育到一定程度后,再被植入动物子宫中使动物怀孕,便可产下与提供细胞者基因相同的动物。这一过程中如果对供体细胞进行基因改造,那么无性繁殖的动物后代基因就会发生相同的变化。,克隆羊诞生图示,Naturalcloneisonethatoccursinanaturalformofcloningwithouthumanhelp.,Man-madecloneisonethatproducedthroughhumanintervention(介入).,Inpairs,lookatthesepicturesanddiscusswhichonesarenaturalclonesandwhichonesareman-made.Explainhowtheydiffer.,Discussion,一株草莓依靠它沿地“爬走”的匍匐茎,一年内就能长出数百株草莓苗,Astrawberryplant,Thenewplantsthatgrowfromtherunnersareexactcopiesoftheoriginalplant.,一株草莓依靠它沿地“爬走”的匍匐茎,一年内就能长出数百株草莓苗,富贵竹插枝即活,仙人掌每块落地就生根,Twins,Naturalclone,Dollythesheep,Shewasclonedwhiletheotherswerebornnaturally.Dollywasa_sheep.,cloned,HowdoesDollydifferfromothersheep?,man-madeclone,1996cloningsheeps,2001cloningcattle,我国成功繁殖克隆兔体形要比普通兔大许多,2002年5月中旬成功地繁殖了一只胚胎细胞克隆兔。,2002cloningcats,第一只克隆宠物猫,克隆马及其“母亲兼姐姐”,2002年4月十六日美国第一头克隆牛“艾米”产下牛犊喜作妈咪,2005cloningdogs,克隆的荧光小猪(左)和正常小猪(右),富贵竹插枝即活,Thegardenershouldcuttheplant,thenthecuttingproduceanothernewplant.,Twins,Theyarebornnaturallyandidenticalinsexandappearance.,Pre-readingListthequestionsyouwanttofindout,Whatisclone?Howiscloneproduced?Whatbenefitscanhumangainfromcloning?Whatproblemsmayarisewhenhumanbeingsarecloned?,1.Whatisclone?Cloneisawayofmakinganexactcopyofanotheranimalandplant;Acloneisgroupofcellsororganismsthataregeneticallyidenticalandhavebeenproducedasexuallyfromthesameoriginalcell.Theyincludenaturalandman-madeclones.2.Howiscloneproduced?Thishappensinplantswhengardenerstakecuttingsfromgrowingplantstomakenewones,andwhensmallpartsofaplantaretakenandgrowninalaboratory.Italsohappensinanimalswhentwinsidenticalinsexandappearanceareproducedfromthesameoriginalegg.,3.Whatbenefitscanhumangainfromcloning?4.Whatproblemsmayarisewhenhumanbeingsarecloned?,1)Itcanhelpcureseriousdiseases2)Itcanhelpcoupleswhohavenobabytobearanewbaby.,1)Peoplemaywanttoclonethemselvessothattheycanliveforever.2)Peoplewanttoclonedeadchildren3).Peoplemaywanttoclonetheirfavoritepets,Reading,Readthepassageandfindoutthemainideaofeachparagraph.,Skimming,Pleasereadthepassageandgetthemainidea,Para.1Para.2Para.3Para.4Para.5,cloningisawayofmakinganexactcopyofanotheranimalorplant.,cloninghastwomajoruses.,TheproblemsofDolly,TheeffectofDolly,Itisforbiddentoclonehumanbeing,Cloningisawayofmakinganexactcopyofanotheranimalandplant.,Whatiscloning?,Ithappensbothin_andin_.Theycanbeclonedby_and_.,plants,animals,themselves,humans,Naturalclone,Man-madeclone,Para1,Thedefinitionofcloning,1.Howmanymajorusesdocloninghave?Firstly,commercialSecondly,research2.WhenwasthecloningofDollythesheepborn?,Para2,1996,Themajorusesandproceduresofcloning,Atfirst,thefactthatDollydeveloped_inanaturalwaywas_.Later,thenews_shelivedforsixyears,halfthelengthofthelifeofthe_onewas_.Finally,theproblemthatoccurredtothescientistswasthataclonedanimallives_theoriginalone.,Para3,TheproblemsofDolly,normally,encouraging,orginal,that,aslongas/shorterthan/longerthan,disturbing,shorterthan,Theword“controversial”inpara4probablymeans_.A.complicatedB.arguableC.important,Para4,TheimpactofDolly,Trueorfalse:1PeoplefearedthatClonedHitlerswoulddoharmtotheworld.2Alltheresearchintohumanbeingswillbeforbidden.3Somecountrieswillusecloninginawiseway.,Para5,Peoplesreactiontocloning,Manygovernmentsforbader