阅读完形专练 - 学生版.docx

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1、启东市汇龙中学主备人：周红英审核人：吴惠平Apr.12,2017阅读完形专练一、阅读理解AHowdoesyourskinsmell?Prettywell,asitturnsout,thankstoreceptorsthatcanbefoundalloveryou.What’smore,theycouldhelpyouheal.Therearemorethan350typesofolfactory(嗅觉)receptorsinthenose,noticingdifferentscents.About150arealsofoundi

2、nbodyissuessuchasthoseoftheheart,liverandgut(胃)，buttheyarehardtostudy.HannsHatt’slabatRuhrUniversityBochuminGermanyfocusedonskin,whichiseasiertostudy,andtastedtheresponsetoscents(pleasantsmells)ofreceptorsinkeratinocytes(角质化细胞)，themainskincelltype.Theyfoundthatanolfa

3、ctoryreceptorinskincalledOR2AT4respondtoman-madesandalwood(檀香)perfumesandskincareproducts.Ratherthansendingamessagetothebrain,asnosereceptorsdo,thereceptorcausedcellstodivideandmigrate,importantprocessesinrepairingdamagedskin.Cellgrowthincreasedby32percentandcellmigr

4、ationbynearlyhalfwhenkeratinocytesinatesttubeweremixedforfivedayswithman-madesandalwood.“Thereisabigtrendtowardsolfactoryreceptorsbeingfoundelsewhereinthebodydoingotherjobs.”SaysJoelMainlandotheMonellChemicalSensesCenterinPhiladelphia.Soitisnotunexpectedtofindrecepto

5、rsinskin,butitisasurprisetolearnthattheyareinvolvedinwoundhealing.HattandMainlandbothcautionthattheseolfactoryreceptorsareveryfinelyadjusted,asisshownbytheirdistinguishingbetweenvariousman-madekindsofsandalwood.Andthereisgeneticvariabilityinhumanreceptors,soyourrecep

6、tormightbeabitdifferentfromyourneighbor’s.Itleavesopenthequestionofwhetherreceptorsmightdiffersomuchbetweenindividualsthattheman-madesandalwoodthatbenefitsonepersonmightbeuselessorevenpoisonoustoanotherHattsaysthe150-200olfactoryreceptorsidentifiedintissueoutsidethen

7、oserepresentanewfamilyoftargetsforexperimentsandnewopportunitiestotreatdisease.Treatmentsthathealwoundsandrepairtheeffectsofageingintheskinarelikelytobetheeasiesttodevelop,hesays.Understandingreceptorsoninternal(insideyourbody)organsandcreatingbeneficialdrugsislikely

8、totakelonger.()1.WhatcanwelearnaboutOR2AT4?A.Itisakindofnosekeratinocyte.B.Itworkslikeanosereceptor.C.Itcanhelpdamagedskinrecover.D