首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
The genetic characteristics of all life forms on earth are embodied in the chemical structure of DNA molecules. An organism’s DN
The genetic characteristics of all life forms on earth are embodied in the chemical structure of DNA molecules. An organism’s DN
admin
2010-07-14
26
问题
The genetic characteristics of all life forms on earth are embodied in the chemical structure of DNA molecules. An organism’s DNA molecules provide a complete blueprint for its physical makeup. Genetic engineering is the process of altering the DNA genetic code to change the characteristics of plants and animals. Through the process, scientists can literally build to order new life forms that perform desired functions. For hundreds of years, humans have engineered the development of food crops and domesticated animals through selective breeding practices. For example, the modern dairy cow is the result of centuries of carefully breeding individual animals that carried the genetic trait for high milk production. However, new technology makes it possible for scientists to restructure the DNA molecules themselves and thus obtain more rapid and more radical genetic changes than were possible in the past. This new process is commonly called recombinant DNA technology or gene splicing because it involves disassembling the DNA molecule and then recombining or splicing the pieces according to a new pattern. The gene-spliced DNA molecule may have a genetic code that has never existed before.
Although recombinant DNA technology is still in its infancy, it has al ready demonstrated its value. New crop breeds produced by this process are already growing in farmers’ fields. Crops that are genetically engineered to resist pests, diseases, and drought could be important in efforts to alleviate starvation around the world. Scientists are trying to use genetic engineering to produce important drugs such as insulin (胰岛素) and interferon (干扰素) cheaply. They are also working on a genetically engineered generation of wonder drugs to combat cancer and other killer diseases. However, the recombinant DNA technology brings with it problems our society has not previously faced. Gene splicing could produce new disease microorganisms, deadly to us or to the plants and animals upon which we depend. The possibility of altering human genetic structure raises serious moral, political, and social is sues. Genetic engineering illustrates dramatically the promises and dangers of technological development. The decisions our society makes about genetic engineering will undoubtedly have tremendous consequences in the years to come.
The word "alleviate" (Paragraph 2) is nearest in meaning to ______.
选项
A、relieve
B、avoid
C、eliminate
D、terminate
答案
A
解析
转载请注明原文地址:https://jikaoti.com/ti/FgFMFFFM
0
大学英语六级
相关试题推荐
THEBLENDINGOFTHEUNITEDSTATESForyears,JorgeDelPinal’sjobasassistantchiefoftheCensusBureau’sPopulationDivi
Googleisaworld-famouscompany,withitsheadquartersinMountainView,California.ItwassetupinaSiliconValleygaragei
Googleisaworld-famouscompany,withitsheadquartersinMountainView,California.ItwassetupinaSiliconValleygaragei
A、Sheangeredthemodels.B、Peoplethoughtshewasadesigner.C、Peoplethoughtshewasamodel.D、Shegotapurpledress.C女人说她
A、Germany.B、Japan.C、TheU.S.D、TheU.K.B根据录音it(workinghours)exceedseverycountrybutJapan...,意味美同人的工作时间比除日本以外的所有国家都长,不难推
A、Shethinksbigpartiesaretooimpersonal.B、Shewouldliketoinvitefriendstoabigparty.C、Shefeelsshehastospendal
AIDSThediseaseAIDShasbecometheleadingcauseofdeathamongyoungadultsinAmerica.MuchrecentAmericanculturedeal
Iflifeexpectancywereamarathon,theUnitedStatesisfadingfromthepack.Althougheveryoneislivinglonger,theinhabitan
WhatSelectivityMeansforYouUnderstandingAdmissionFactorsCollegeadmissionofficersacrossmostofthenationrepo
随机试题
首选大环内酯类抗生素治疗的肺炎是
年轻恒牙发生牙髓、根尖周病变后,诱导根尖形成所依赖的组织有
8个月男婴,咳嗽3天,发热伴气促1天,查体:呼吸急促,口周略发青,咽部充血,双肺闻及中小水泡音,心、腹(-):白细胞10×109/L,N0.65,L0.35,其最可能的诊断是
A、简单扩散B、易化扩散C、膜孔扩散D、胞饮E、主动转运小分子水溶性高的药物可通过
项目采购的对象包括()。
财政金库存款由( )直接掌握。
《狐狸和乌鸦》教学片断:学习了课文最后一段,教师打出幻灯片:乌鸦寂寞地站在一棵树上。师:请小朋友仔细观察这只乌鸦的神态,想一想:看着狐狸叼起肉进洞,她心中会想些什么?(学生稍加思考,纷纷举起了小手)生:乌鸦很伤心,心想:哎!都怪我爱听好话,才会上当。生:乌
t为int类型,进入下面的循环之前,t的值为0。while(t=1){...}则以下叙述中,正确的是()。
HowtoBeaSuccessfulBusinesspersonHaveyoueverwonderedwhysomepeoplearesuccessfulinbusinessandothersarenot?
TheWeightExperimentNicolaWaltershasbeentakingpartinexperimentsinScotlandtodiscoverwhyhumansgainandlosewe
最新回复
(
0
)