考研英语阅读模拟试题及答案doc

本文格式为Word版，下载可任意编辑——考研英语阅读模拟试题及答案docIthaslongbeenknownthattherateofoxidativemetabolismtheprocessthatusesoxygentoconvertfoodintoenergyinanyanimalhasaprofoundeffectonitslivingpatterns.Thehighmetabolicrateofsmallanimals，forexample，givesthemsustainedpowerandactivityperunitofweight，butatthecostofrequiringconstantconsumptionoffoodandwater.Verylargeanimals，withtheirrelativelylowmetabolicrates，cansurvivewellonasporadicfoodsupply，butcangen-eratelittlemetabolicenergypergramofbodyweight.Ifonlyoxidativemetabolicrateisconsidered，there-fore，onemightassumethatsmaller，moreactive，animalscouldpreyonlargerones，atleastiftheyattackedingroups.Perhapstheycouldifitwerenotforanaerobicglycolysis，thegreatequalizer.Anaerobicglcolysisisaprocessinwhichenergyisproduced，withoutoxygen，throughthebreakdownofmuscleglycogenintolacticacidandadenosinetri-phosphateATP，theenergyprovider.Theamountofenergythatcanbeproducedanaerobicallyisafunctionoftheamountofglycogenpresent-inallvertebratesabout0.5percentoftheirmuscleswetweight.Thustheanaerobicenergyreservesofaverte-brateareproportionaltothesizeoftheanimal.If，forexample，somepredatorshadattackeda100-tondinosaur，normallytorpid，thedinosaurwouldhavebeenabletogeneratealmostinstantaneously，viaanaerobicglycolysis，theenergyof3，000humansatmaximumoxidativemetabolicenergyproduction.Thisexplainshowmanylargespecieshavemanagedtocompetewiththeirmoreactiveneighborsthecompensationforalowoxidativemetabolicrateisglycolysis.Therearelimitations，however，tothiscompensa-tion.Theglycogenreservesofanyanimalaregood，atmost，foronlyabouttwominutesatmaximumeffort，afterwhichonlythenormaloxidativemetabolicsourceofenergyremains.Withtheconclusionofaburstofactivity，thelacticacidlevelishighintthebodyfluids，leavingthelargeanimalvulnerabletoattackuntiltheacidisreconverted，viaoxidativemetabolism，bytheliverintoglucose，whichisthensentinpartbacktothemusclesforglycogenresyn-thesis.Duringthisprocesstheenormousenergydebtthattheanimalhasrunupthroughanaerobicglycolysismustberepaid，adebtthatisproportionallymuchgreaterforthelargervertebratesthanforthesmallerones.Whereasthetinyshrewcanreplaceinminutestheglycogenusedformaximumeffort，forexample，thegiganticdinosaurwouldhaverequiredmorethanthreeweeks.Itmightseemthatthisinter-minablylongrecoverytimeinalargevertebratewouldproveagravedisadvantageforsurvival.Fortunately，muscleglycogenisusedonlywhenneededandeventhenonlyinwhateverquantityisnecessary.Onlyintimesofpanicorduringmortalcombatwouldtheentirereservesbeconsumed.1.Whatisthetextmainlyabout。

[A]refuteamisconceptionaboutanaerobicglycolysis.[B]introduceanewhypothesisaboutanaerobicglycolysis.[C]describethelimitationsofanaerobicglycolysis.[D]explainanaerobicglycolysisanditseffectsonanimalsurvival.2.Accordingtotheauthor，glycogeniscrucialtotheprocessofanaerobicglyrolysisbecauseglycogen[A]increasestheorganism‘sneedforATP.[B]reducestheamountofATPinthetissues.[C]isaninhibitoroftheoxidativemetabolicproductionofATP.[D]isthematerialwhichATPisderived.3.Itisimpliedthatthetotalanaerobicenergyreservesofavertebrateareproportionaltoitssizebecause[A]largervertebrateconservemoreenergythansmallervertebrates.[B]largervertebratesuselessoxygenperunitweightthansmallervertebrates.[C]theabilityofavertebratetoconsumefoodisafunctionofitssize.[D]theamountofmuscletissueinavertebrateisdirectlyrelatedtoitssize，4.Accordingtothetext，amajorlimitationofanaerobicglycolysisisthatitcan[A]produceinlargeanimalsmorelacticacidthanthelivercansafelyreconvert.[B]necessitateadangerouslylongrecoveryperiodinlargeanimals.[C]reduceenergymoreslowlythanitcanbeusedbylargeanimals.[D]consumealloftheavailableglycogenregardlessofneed.5.Whichofthefollowingaudiencesistheauthormostprobablyaddressing[A]Collegestudentsinanintroductorycourseonanimalphysiology.[B]Historiansofscienceinvestigatingthediscoveryofanaerobicglycolysis.[C]Graduatestudentswithspecializedtrainingincomparativeanatomy.[D]Zoologistsinterestedinprehistoricanimals.