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时间:2019-11-13
《2019-2020年高考英语一轮复习 Unit2 Cloning导学案 新人教版选修8》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、2019-2020年高考英语一轮复习Unit2Cloning导学案新人教版选修8ReadingCLONING:WHEREISITLEADINGUS?Cloninghasalwaysbeenwithusandisheretostay.Itisawayofmakinganexactcopyofanotheranimalorplant.Ithappensinplantswhengardenerstakecuttingsfromgrowingplantstomakenewones.Italsohappens
2、inanimals1.________twinsidenticalinsexandappearanceareproducedfromthesameoriginalegg.Thefactisthatthesearebothexamplesofnaturalclones.Cloninghastwomajoruses.Firstlygardenersuseitallthetimetoproducemercialquantitiesofplants.Secondly,itisvaluableforresea
3、rchonnewplantspeciesandformedicalresearchonanimals.Cloningplantsisstraightforward2._______cloninganimalsisveryplicated.Itisadifficulttask3.______________(undertake).Manyattemptstoclonemammalsfailed.Butatlastthedeterminationandpatienceofthescientistspai
4、doffin1996withabreakthrough—thecloningofDollythesheep.Theprocedureworkslikethis:1.FemalesheepAprovidesaneggcell.2.Thenucleusisremovedfromtheeggcell.3.Theeggcellisreadyforanewnucleus.4.FemalesheepBprovidesasomaticcellfortheclone.Thenucleusofthiscellcont
5、ainsallthegenesneededtoproduceanewsheep.5.Thenucleusistakenoutofthesomaticcell.6.ThenucleusfromsheepBandtheeggcellfromsheepAarejoinedusingelectricity.7.Thecelldividesandgrowsintoanembryo.8.TheembryoisputintofemalesheepC,whobeesthecarrieroftheclone.9.Th
6、elambisthecloneofthedonatedcellfromSheepBwhichprovidedthenucleus.Ontheonehand,thewholescientificworldfollowedtheprogressofthefirstsuccessfulclone,Dollythesheep.Thefactthatsheseemedtodevelopnormallywasvery4._____________(encourage).Thencamethedisturbing
7、news5.__________Dollyhadbeeseriouslyill.Cloningscientistswerecastdown6._________(find)thatDolly’sillnessesweremoreappropriatetoamucholderanimal.AltogetherDollylivedsixandahalfyears,halfthe7.________(long)ofthelifeoftheoriginalsheep.8._________[尽管]herpr
8、oblems,Dollysuccessfullyproducedalambina9.___________(nature)birth.Sadlythesamearbitraryfateaffectedotherspecies,suchasclonedmice.Thequestionsthatconcernedallscientistswere:“Wouldthisbe10._____majordifficultyforallclonedanimals?Wouldith
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