高中英语 Unit2第6课时文化背景知识教案 新人教版选修8.docx
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高中英语 Unit2第6课时文化背景知识教案 新人教版选修8.docx
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高中英语Unit2第6课时文化背景知识教案新人教版选修8
英语高二下人教版新课标选修8Unit2第6课时教案(文化背景知识)
I.Readingcomprehension:
Hello,Dolly!
Britishscientistshavedonesomethingthatmanypeoplethoughtwasimpossible:
theycreatedthefirstcloneofanadultmammal.Theclone,namedDolly,isaseven-month-oldsheep,grownfromacellofanadultfemalesheep.
Whatisaclone?
Acloneisacopy,ageneticcopy.Genesaretheinstructionsforlife.Theytellacellwhattodoandhowtodoit.Genesmakeeachindividualplantoranimaldifferentandunique.Butaclonehasthesamegenesastheoriginalorganism.
Cloningisnotnew.Plantshavebeenclonedforcenturies.Newplantsareoftengrownfromcuttingsfromanotherplant.Also,plantslikepineapples,strawberriesandcarnationsaresometimescloned.Onebenefitofcloningisthatwecanmakemanycopiesofthebestandhealthiestplants.
Ithasbeenmuchmoredifficulttocloneanimals.Frogshavebeencloned,buttheydiedastadpoles,neverlivinglongenoughtobecomeadultfrogs.Mice,sheepandcattlehavebeenclonedfromembryos.ButDollyisthefirsthealthycloneofanadultmammal.Howdidtheydoit?
(1)Anunfertilizedeggwastakenfromasheep.
(2)Theeggnucleuswasremoved.
(3)Acellwastakenfromtheudderofapregnantsheep.Itwas“starved”,sothatitstoppedgrowing.
(4)Thetwocellswerecombinedintooneandthenimplantedinathirdsheep,whereitgrewnormally.
(5)Theclonewasborn.Itwasgeneticallyidenticaltothepregnantsheepinstep(3).
Thissoundsmucheasierthanitactuallywas.Toendupwithoneclone,thescientistsstartedwith277uddercells.Andtheyneededinawaytomaketheeggcellacceptanewnucleus.Theydidthatbystarvingthecellinstep(3).
Itmaysoonbepossibletoclonemanytypesofanimals.Willwealsobeabletoclonehumanorgans,orevenwholehumanbeings?
Wehaveonlybeguntothinkaboutthemoralityofcloningtechnology.Maybethequestiontoaskisnotwhetherwecanclonehumans,butinstead,shouldweclonehumans?
1.Dollyisasheepbecausesheisgrownfromacellofanadultfemalesheep_____.
A.thathasnotherfather
B.thathasnothermother
C.thathasnoparents
D.thathasnotanytail
2.TellwhichofthefollowingstatementsisTRUE.
A.Onlyplantscanbecloned.
B.Onlystrawberriesandcarnationscansometimesbecloned.
C.Animalsandplantshavequitealonghistoryofcloning.
D.Genescantellacellwhattodoandhowtodoitduringcloning.
3.Fromthefourthparagraphwecanknowthat_____.
A.atadpoleistheearlystageofagrown-upfrog
B.atadpoleisafrogwithoutatail
C.atadpoleisapoolwherefrogscanlive
D.atadpoleisacloneofanadultmammal
4.Whatistherightorderintheprocessoftheclone
ofDolly?
a.Takinganunfertilizedeggfromanadultfemalesheep.
b.Removingtheegg’snucleus.
c.Combiningthetwocellsintooneandthenimplantingitinathirdsheep.
d.Takingacellfromtheudderofapregnantsheep.
A.abcdB.cabd
C.abdcD.dcba
答案与分析
本文是科普时文阅读。
全文讲述了克隆羊多莉的出生过程。
1.C从文章中可以看出,多莉是从一只成年羊的细胞中克隆出来的,所以它根本没有父母,而是那只羊的一个翻版。
A项“它没有父亲”、B项"它没有母亲"说得太片面,D项“它没有尾巴”不符合题意。
2.D题意为“下面哪句话是对的”,D项“基因在克隆过程中可以告诉细胞做什么及如何去做”,文中第二段正是说的这个意思。
第三段指植物可以克隆,第四段指动物也可以克隆,所以选项A“只有植物可以克隆”不正确。
从文中第三段可知菠萝也是可以克隆的,所以B项“只有草莓和康乃馨有时可以克隆”不正确。
第三段中指植物已有几个世纪的克隆历史,而没有提到动物的克隆历史,所以与C项“动、植物都有一个相当长的克隆历史”与题意不符。
3.A文中第四段第二句中说:
人们曾经克隆过青蛙,但在蝌蚪阶段就死了,并没有活到成年青蛙阶段,所以我们可以判断,蝌蚪是青蛙的早期形态,故A项“蝌蚪是成年青蛙的早期形态”正确。
B项“蝌蚪是没有尾巴的青蛙”、C项“蝌蚪是青蛙生存的池塘”、D项“蝌蚪是成年哺乳动物的克隆体”与实际不符。
4.C题意为“克隆多莉的正确顺序是什么”,从文中第四段后半部分的内容可知,正确顺序应是C项中所说的。
Ⅱ.AboutCloning
Quiteafewpeoplemighttakeanegativeattitudetowardscloning.Theyarguethatcloningwillarousealotofmoralandethicalproblemsandthatsomepeoplewouldusethetechniquetodevelopcrime(Howwillyoufeeltofaceayoungerbutidenticaltwinofyouyourself?
).Allthattheyworryaboutaretrue.Butaseverycoinhastwosides,cloningisnoexception.
Eventhefatheroftheworld’sfirstcloneDollyisnotforcloning.Buthesimplygoesagainstcloningpeople.
Butwhatiscloneanyway?
UptonowDollyistheonlycloneintheworld.Shewascreatednotoutofthenaturalwaytheunionofaspermandaneggthatwearefamiliarwith,butoutofthegeneticmaterialfromanuddercellofasix-year-oldsheep.TheembryologistWilmutfusedtheuddercellwithaneggfromanothersheep,afterfirstremovingallgeneticmaterialfromtheegg.Theuddercell’sgenestookupresidenceintheegganddirectedittogrowanddevelopandanidenticaltwinoftheoriginalsheep,Dollywasresulted.Andthatishowacloneisborn.
Ascloningisnolongerasciencefiction,andwiththebirthofDolly,thewholeworldbeginstofocusonthesehightechnologyandthatgenerateasevereargumentmentionedatthebeginningofthearticle.Isitthatfrighteningwhenspeakingofcloning?
Theanswerisyes.
I’mnotdenyingthatclonehascertaindisadvantages.Actuallycloneisadouble-edgesword,wehavetoadmit.Butwecanmakethebestofitsbrightside.Willyouadmiretherose’sbeautyasyouusedtowhenyoudiscoveritsthorn?
Weallknowthatitisjustbecausetherapiddevelopmentofeconomythathasledtothepollutedenvironmentandthereforebringsalotofdiseasesandmanyananimal’sdyingout.Canwejuststopmodernizingbecauseofthis?
Theanswersarecertainlyno.Suchisthecaseascloning.Wecangainalotfromitifusedproperly.Wecancloneorganspatientsneedbadlytohelpreducetheirpainandevensavetheirlivesbecausetheyaretheperfectmatch.Wecanalsomakeanextinctcreationbacktolivewhennecessary.Thelistgoesonandon.
Therearenevergoingbesufficientreasonsthatweshouldstopdoingresearchonthefieldofcloning.Instead,thefutureofcloningisprosperous.
Sincetheharmcannotbeavoided,atleastwecantrytoputittotheleast.Butitturnsouttobethegovernment’sduty.Inaddition,theclonetechniquehasnotgrownmatureyet.Whattroublesusnowisreallyhowtomaketheprogramasuccessfulone.
Takeasecondthought,andyoumightbeforcloningtoo.
Ⅲ.QuestionsaboutCloning
1.Whyclone?
Researchadvancesoverthepastdecadewhichhavetoldusthat,withalittlework,wehumanscanclonejustaboutanythingwewant,fromfrogstomonkeysandprobablyevenourselves!
So,wecanclonethings,butwhywouldwewantto?
Let’slookatsomeofthereasonspeoplegivetojustifycloning.
A.Cloningformedicalpurposes
Ofallthereasons,cloningformedicalpurposeshasthemostpotentialtobenefitlargenumbersofpeople.Howmightcloningbeusedinmedicine?
a.Cloninganimalmodelsofdisease
Muchofwhatresearcherslearnabouthumandiseasecomesfromstudyinganimalmodelssuchasmice.Often,animalmodelsaregeneticallyengineeredtocarrydisease-causingmutationsintheirgenes.Creatingthesetransgenicanimalsisatime-intensiveprocessthatrequirestrial-and-errorandseveralgenerationsofbreeding.Cloningtechnologiesmightreducethetimeneededtomakeatransgenicanimalmodel,andtheresultwouldbeapopulationofgeneticallyidenticalanimalsforstudy.
b.Cloningstemcellsforresearch
Stemcellsarethebody’sbuildingblocks,responsiblefordeveloping,maintainingandrepairingthebodythroughoutlife.Asaresult,theymightbeusedtorepairdamagedordiseasedorgansandtissues.Researchersarecurrentlylookingtowardcloningasawaytocreategeneticallydefinedhumanstemcellsforresearchandmedicalpurposes.c.“Pharming”fordrugproduction
Farmanimalssuchascows,sheepandgoatsarecurrentlybeinggeneticallyengineeredtoproducedrugsorproteinsthatareusefulinmedicine.Justlikecreatinganimalmodelsofdisease,cloningmightbeafasterwaytoproducelargeherdsofgeneticallyengineeredanimals.
B.Revivingendangeredorextinctspecies
HaveyouseenJurassicPark?
Inthisfeaturefilm,scientistsuseDNApreservedfortensofmillionsofyearstoclonedinosaurs.Theyfindtrouble,however,whentheyrealizethattheclonedcreaturesaresmarterandfiercerthanexpected.Couldwereallyclonedinosaurs?
Intheory?
Yes.Whatwouldyouneedtodothis?
Awell-preservedsourceofDNAfromtheextinctdinosaurandacloselyrelatedspecies,currentlyliving,thatcouldserveasasurrogatemother.Inreality?
Probablynot.It’snotlikelythatdinosaurDNAcouldsurviveundamagedforsuchalongtime.However,scientistshavetriedtoclonespeciesthatbecameextinctmorerecently,usingDNAfromwell-preservedtissuesamples.
C.Reproducingadeceasedpet
Nojoke!
Ifyoureallywantedto,andifyouhadenoughmoney,youcouldcloneyourbelovedfamilycat.AtleastonebiotechnologycompanyintheUnitedStatesofferscatcloningservicesfortheprivilegedandbereaved,andtheyarenowworkingtoclonedogs.Butdon’tassumethatyourclonedkittywillbeexactlythesameastheoneyouknowandlove.
Themainreasontocloneplantsoranimalsistomassproduceorganismswithdesiredqualities,suchasaprize-winningorchidorageneticallyengineeredanimal—forinstance,sheephavebeenengineeredtoproducehumaninsulin.Ifyouhadtorelyonsexualreproduction(breeding)alonetomassproducetheseanimals,andthenyouwouldruntheriskofbreedingoutthedesiredtraitsbecausesexualreproductionreshufflesthegeneticdeckofcards.
Otherreasonsforcloningmightincludereplacinglostordeceasedfamilypetsandrepopulatingendangeredorevenextinctspecies.Whateverthereasons,thenewcloningtechnologieshavesparkedmanyethicaldebatesamongscientists,politiciansandthegeneralpublic.Severalgovernmentshaveconsideredorenactedlegislationtoslowdown,limitorbancloningexperi
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