小学、初中、高中各种试卷真题知识归纳文案合同PPT等免费下载www.doc985.com课时作业(二)Unit1SectionⅡGrammarandusage&IntegratedskillsⅠ.阅读理解ACellsinourbrainusuallysend“stopeating”signalwhenwe'vehadenough.Butaftermiceatefattyfoodsforjusttwoweeks,theirbrains'brakeonovereatingquieteddown.Thatfindingmayhelpexplainthecomplexlinkbetweenfoodandappetitethatcanbecomedisorderedwhenpeopleovereat.Foodisessentialtolife.Ourbrainshave,therefore,evolvedaseriesofsystemstomakesureweeatenough.GarretStuber,aneuroscientistattheUniversityofWashington,togetherwithhisteamtookaimatonebrainareaknowntobeinvolvedineatingbehaviors.Thislateralhypothalamus(下丘脑外侧区)containsmanydiversecells.Stuber'sgrouplookedatthebehaviorsofgenesinthecellshere.Andinonetype—glutamatergicnerve(谷氨酸能神经)cells—bigdifferencesappearbetweenfatmiceandleanones.EarlierworkbyStuber'sgrouphadsuggestedthatthesecellsactlikeabrakeoneating.Whentheresearcherspreventedthesecellsfromfiring,micesuddenlyoverate.Theyalsofattenedup.Butitwasn'tclearhowthecells'activitychangedasthemicetransitionedfromslimtofat.“Obesitydoesn'tjusthappenovernight，”notesStuber.Tofindoutthesecret,hisgroupundertookanewstudy.Theyfedmicehigh-fatfood.Nowandagain,they'duseafancymicroscopetolookathowwelltheanimals'glutamatergiccellscouldfireoffsignals.Twoweeksintothehigh-fatfood—evenbeforethemicebecameround—theactivityofthesenervecellshadslowed.Itcontinuedastheanimalsgrewlargerovera12-weekperiod.“Thecells'activitywasgoingdownasafunctionofhigh-fatdiet.Theresultssuggestthatthehigh-fatdietisremovingthebrakeoneatingandobesity，”explainsStuber.It'shardtosaywhethersimilarcellsnormallycontrolpeople'sappetite.Brain-imagingtestshaveshownthatthesamebrainregion—thehypothalamus—playsarolewhenpeopleshiftbetweenhungerandfeelingfull.1．Whathappenedafterthemiceatefattyfoodsfortwoweeks?A．Theirappetitewasgettingworse.B．Theirbrainsbecamedisordered.C．Theyrefusedtoeatzerofatfood.D．Theylackedafeelingoffullness.2．Itcanbelearnedfromthetextthatglutamatergicnervecells________．A．areeasilyfoundinleanmiceB．canpreventmicefromovereatingC．functionwellunderanyconditionD．areamainpartoflateralhypothalamus3．WhydidStuber'sgroupundertakethenewstudy?小学、初中、高中各种试卷真题知识归纳文案合同PPT等免费下载www.doc985.com小学、初中、高中各种试卷真题知识归纳文案合同PPT等免费下载www.doc985.comA．Tostudytheroleofglutamatergiccellsinmice'sfatteningup.B．Tofindoutthelinkbetweenhigh-fatdietsandobesity.C．Tofindoutdecidingfactorsinmice'sappetite.D．Tostudytheeatinghabitoffatmice.4．Whatisthemainideaofthetext?A．Obesityinfluencesglutamatergicnerves'function.B.Glutamatergicnervesdecidepeople'sappetite.C．High-fatdietsleadtoovereating.D．Ourbrainscontrolourfoodchoices.BCompetitiveeatinghasbecomeabigbusiness.TheInternationalFederationofCompetitiveEating(IFOCE)holdseventsforcompetitiveeatingallaroundtheworld.Oneofthemostpopularcontests(竞赛)isheldevery4thofJulyonConeyIslandinNewYork.Nathan'sHotDogEatingConteststartedin1916andtheeventhasbeendominated(占据优势)byTakeruKobayashi.TheJapanesecompetitorsethisfirstrecordin2001,whenheate50hotdogsin12minutesandwonthecontestsixyearsinarow.Themaintypesoffoodeateninthecontestsarefastfood.Hotdogs,chickenwings,pickles,corndogsandpizzaaremainfoodsofthecontests.Thecontestsusuallylastfromaround8to12minutes.Nowmostofthecompetitorsaremen,buttherearealsowome...