资源描述：
《2016年职称英语综合类a级阅读理解模拟题及答案》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、2016年职称英语综合类A级阅读理解模拟题及答案 EatMore,WeighLess,LiveLonger Clevergeneticdetectiveworkmayhavefoundoutthereasonwhyanear-starvationdietprolongsthelifeofmanyanimals. RonaldKahnatHarvardMedicalSchoolinBoston,US,andhiscolleagueshavebeenabletoextendthelifespan(寿命)ofmiceby18perc
2、entbyblockingtherodent's(啮齿动物)increaseoffatinspecificcells.Thissuggeststhatthinness——andnotnecessarilydiet——promoteslonglifein"calorie(热量卡)restricted"animals. "It'sverycoolwork,"saysagingresearcherCynthiaKenyonoftheUniversityof California,SanFrancisco."Thesemiceeatal
3、ltheywant,loseweightandlivelonger.It'slikeheaven." Calorierestrictiondramaticallyextendsthelifespanoforganismsasdifferentaswormsandrodents.Whetherthisworksinhumansisstillunknown,partlybecausefewpeoplearewillingtosubmittosuchastrictdiet. Butmanyresearchershopetheywil
4、lbeabletotriggerthesameeffectwithadrugoncetheyunderstandhowlessfoodleadstoalongerlife.Onetheoryisthateatinglessreducestheincreaseofharmfulthingsthatcandamagecells.ButKahn'steamwonderedwhethertheanimalssimplybenefitbybecomingthin. Tofindout,theyusedbiologytrickstodisr
5、upttheinsulin(胰岛素)receptor(受体)geneinlabmice——butonlyintheirfatcells."Sinceinsulinisneededtohelpfatcellsstorefat,theseanimalswereprotectedagainstbecomingfat,"explainsKahn. Thisslightgeneticchangeinasingletissuehaddramaticeffects.Bythreemonthsofage,Kahn'smodifiedmiceha
6、dupto70percentlessbodyfatthannormalcontrolmice,despitethefactthattheyate55percentmorefoodpergramofbodyweight. Inaddition,theirlifespanincreased.Theaveragecontrolmouselived753days,whilethethinrodentsaveragedalifespanof887days.Afterthreeyears,allthecontrolmicahaddied,b
7、utone-quarterofthemodifiedrodentswerestillalive. "Thattheygettheseeffectsbyjustmanipulatingthefatcellsiscontroversial,"saysLeonardGuarenteoftheMassachusettsInstituteofTechnology,whostudiescalorierestrictionandaging. ButGuarentesaysKahnhasyettoprovethatthesameeffecti
8、sresponsibleforincreasedlifespanincalorie-restrictedanimals."Itmightbethesameeffectortheremightbetworoutestolonglife,"hepoin
