2020版高考英语大一轮复习课时达标37Unit2Cloning（含解析）新人教版选修8

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1、课时达标(三十七)Unit2Cloning建议时间/35分钟阅读理解A课标话题人与自然·自然科学研究成果体裁说明文词　　数311难度Chinesescientistsrecentlyhaveproducedtwomonkeyswiththesamegene,ZhongZhongandHuaHua,usingthesametechniquethatgavetoDollythesheep.Thesemonkeysarenotactuallythefirstprimates(灵长类)tobecloned.Anotheronenamed

2、Tetrawasproducedinthelate1990sbyembryo(胚胎)splitting,thedivisionofanearly－stageembryointotwoorfourseparatecellstomakeclones.Bycontrast,theywereeachmadebyreplacinganeggcellnucleus(细胞核)withDNAfromadifferentiatedbodycell.ThisDollymethod,knownassomaticcellnucleartransfer(

3、SCNT),cancreatemoreclonesandallowsresearchersgreatercontrolovertheeditstheymaketotheDNA.Successcamefromadoptingseveralnewtechniques.Theseincludedanewtypeofmicroscopytobetterviewthecellsduringhandlingorusingseveralmaterialsthatencouragecellreprogramming,whichhadn'tbee

4、ntriedbeforeonprimates.Still,theresearchprocessproveddifficult,andmanyattemptsbytheteamfailed.Justtwohealthybabymonkeysbornfrommorethan60testedmothers.Thisleadstomanyresearchers'pouringcoldwaterontheideathattheteam'sresultsbringscientistsclosertocloninghumans.Theytho

5、ughtthisworkisnotasteppingstonetoestablishingmethodsforobtaininglivebornhumanclones.Instead,thisclearlyremainsaveryfoolishthingtoattempt,itwouldbefartooinefficient,fartoounsafe,anditisalsopointless.Butthescientistsinvolvedemphasizethatthisisnottheirgoal.Thereisnownob

6、arrierforcloningprimatespecies.Thuscloninghumansisclosertoreality.However,theirresearchpurposeisentirelyforproducingnon－humanprimatemodelsforhumandiseases;theyabsolutelyhavenointention,andthesocietywillnotpermitthisworktobeextendedtohumans.Despitelimitations,theytrea

7、tthisbreakthroughasanovelmodelsystemforscientistsstudyinghumanbiologyanddisease.语篇导读　中国科学家利用SCNT技术克隆出了两只猴子，文章介绍了相关信息并讨论了这种克隆实验的影响。1．WhatdoweknowaboutthetechnologycalledSCNT?A．Itcreatedthefirsttwoprimates.B．ItmaycontributetoeditingtheDNA.C．Itcandivideanearly－stageembr

8、yointoseveralcells.D．Itproducedtwoclonedmonkeyswithdifferentgenes.解析　B　细节理解题。根据第一段最后一句可知，SCNT可以帮助研究者在编辑DNA时更加有效控制，即可能有助于编辑DNA，故选B项。