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英语第8册第2单元VIP免费

英语第8册第2单元_第1页
1/23
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Unit2CloningSectionⅠWarmingUp&Reading—Pre-reading1.Whataretheadvantagesanddisadvantagesofcloning?2.Notonlyanimalsbotalsoplantscanbecloned.Doyouknowthedifferencebetweenthem?Pleasereadthefollowingpassagetogettheanswer.Anewstudyofplantsthatarereproducedhycloninghasshownwhyclonedplantsarenotldentlcal.Scientistshaveknownorsorfletimethatclonedorganismserenotalwaysidcntical:theirobservablecharacteristicsandtraitscanvary,andthisvariationcanbepassedontotileiicxtgeneration.Thisisdcspirethefactthattheyatederived(获得)fromgenedcallyidenticalfoundercells.Now,ateamfromOxfordUniversity,theUK.andKingAbdu№hUniversityofScienceandTechnology,SaudiArabia,believetheyhavefoundoutwhythisisthecaseinplants:thegenomes(染色体)ofregenerateplantscarryrelativelyhighfrequenciesofnewDNAsequencemutations(变异)thatwerenotpresentinthegenuineofthedonorplant.Theteamreportedtheirfindingsinthisweek’sCurrentBiology.“Wherethesenewmutationsactuallycoomfromisstillamystery,”saidProfessorHarberd.“TheymayariseduringtheregenerationprocessitselforduringthecelldivisionsinthedonorplantthatgaverisetotherootceilsfromwhichtheregenerateplantsarecreatedWeareplanrlingfurtherresearchtofindoutwhichofthesetwoprocessesisresponsibleforthesemutations.WhatwecanSaylsthatnaturehassafelybeenemployingwhatyoumightcalla‘cloning’processinplantsfoTmillionsofyears,andthattheremustbcgoodevolutionaryreasollswhythesemutatlonsareintroduced.”Thenewresultssuggestthatvariationinclonesofplantsmayhavediffcrentunderlyingcausesfromthoseofvariationincloncsofanlmalswhereitisbelievedthattheeffectofenvironmerltalfactorsonhowanimalgenesareexpressedisnloreimportantandnosimilarhighfrequenciesofmutationshavebeenobserved.ProfessorHarberdsaid,“WhileourrcstlltShighlightthatclonedplantsaadanimalsareverydifferent,theymaygiveusinsightsintohowbacterialandcancercellsrcplicatethcmselves,andhowmuutationsariseduringtheseprocesseswhich,ultimately,haveanimpactonhumanhealth.”Step1WarmingUp1.Howmuchdoyouknowaboutclone?Whatisclone?Andwhatarenaturalcloneandman—madeclone?2.Lookatthesepicturesandtellwhichonesarenatu一ralclonesandwhichonesareman—made.3.Seeanotherkindofclone.Thetwowomensoldierslookveryalike.Canyouexplainwhy?Step2FastReading11.Readthetextandwritedownthemainideaofthetext.ThetextismainlyabouttheofanimalcIoningandthelifeofDollythesheep,aswellasthereasonswhycloningisstill.2.Readthetextandthenfindthemainideaofeachparagraph.Paragraph1()a.TheeffectofDolly.Paragraph2()b.Themajorusesofcloning.Paragraph3()C.People’Sreactiontocloning.Paragraph4()d.Thedefinition(定义)ofcloning.Paragraph5()e.TheproblemofDolly.Step3.CarefulReadingReadthetextandthenchoosethebestansweraccordingtothetext.(1)WhichofthefollowingstalementsaboutcloningisNOTtrueaccordingtothetext?A.Cloningissomethingthathasbeendevelopedquiterecently.B.Twinsthatlookexactlythesameareoriginallyfromthesameegg.C.Cloningisusedbygardenerstomakemoremonev.D.Animalcloningismuchmoredifficultthanplantclonlng.(2)ThecloningofDollythesheepsucceededbecauseA.it’SeasiertocloneasheepthanotheranimalsB.thescientistsweredeterminedandWOrkedhardwithpatienceC.thescientistswererewardedandgotlotsofmoneyD.manyotherattemptstoclonemammalsfailed(3)Thesheepthatdonatedthesomaticcellmostprobablvlivedyears.A.3B.6C.9D.12(4)WhichofthefollowingisNOTanadvantageofcloning?A.Cloning...

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英语第8册第2单元

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