TheinformationinthepassagesuggeststhatinmiceCRY1mostlikelyaffectsXPA

AAMCFL2B/B

TheinformationinthepassagesuggeststhatinmiceCRY1mostlikelyaffectsXPA

by:

A.activatingXPAproteinactivity.B.activatingtranslationofXPA-encodingtranscripts.C.repressingreplicationoftheXPA-encodinggene.D.repressingtranscriptionoftheXPA-encodinggene.TheanswertothisquestionisDbecauseFigure1showsthatXPAlevelsdecrease asCRY1levelsincrease.ItshowsthatasCRY1increases,XPAactivitydecreases,indicatinganinhibitory effectofCRY1onXPA.SinceXPAisaproteinthatisrepressedbyCRY1,only optionDisviable Whichcellsharvestedfromadultmiceweremostlikelyusedasthehighly proliferativebenchmarkintheexperimentthatgeneratedthedatashowninFigure 3?A.Adipocytes B.Cardiacmusclecells C.Gastrointestinalepithelialcells D.Neurons TheanswertothisquestionisCbecausetheepithelialcellsthatlinethe gastrointestinaltractaretypicallyhighlyproliferative.AfterasectionofaDNAstrandcontainingaUVR-inducedlesionisremovedand resynthesized,thenewlysynthesizedstrandisrejoinedtotheremainderoftheDNA strandbywhattypeofbond?A.Disulfide B.Hydrogen 1 / 3

C.Peptide D.Phosphodiester TheanswertothisquestionisDbecausephosphodiesterbondslinkthe3ʹcarbon atomofonedeoxyriboseandthe5ʹcarbonatomofanotherdeoxyribosewithinthe DNAmolecules.AlPexposedtoanaqueoussolutioninwhichpHrangewillresultinthelargest amountofphosphineproduction?A.pH<4 B.410 TheanswertothisquestionisAbecauseH+isareactant,andtheincreaseinthe concentrationofH+atlowpHwillfavorproductformation.ThelowerthepH,themoreH+ionsonthereactantsside,whichpushesthe equlibriumtowardtheproductsideduetoLeChatlier'sprinciple WhenresearchersdeterminedthetotalcellularconcentrationofATPinAlP-exposed ratlivercells,theyfoundtheconcentrationtobeequaltothecontrolvalue.Which conclusionaboutthemetabolicstateofthecellisbestsupportedbythesedata?A.GlycolyticfluxisincreasedafterAlPtreatment.B.GlycolyticfluxisdecreasedafterAlPtreatment.C.CitricacidcyclefluxisincreasedafterAlPtreatment.D.CitricacidcyclefluxisdecreasedafterAlPtreatment.TheanswertothisquestionisAbecauseATPproductionisthesameinbothcontrol andAlP-exposedcells,andthedatainthepassageshowthatmitochondrialATP productionisdecreased.Thisindicatesthatthefluxthroughglycolysisisincreased, becausethiswouldbethemajorpathwayforATPproductiononcetheelectron transportchainisshutdown. 2 / 3

IftherateofATPlevelswerereducedby65%aftertreatmentwithAIPasstatedin thepassage,thenweresubsiquentlyfoundtobeequaltothecontrolvalue-theonly logicalansweristhatthiswasduetoanincreaseofglycolyticfluxwhichmakesup forthedecreasedATPlevelsduetoAIPinhibitingtheelectrontransportchain.Whywasitnecessaryfortheresearcherstodeterminetheactivityofthecomplexes independentofoneanother?A.Complexstabilityislostifthecomplexesareabletointeractstructurally.B.Thecomplexeshavedifferentcellularlocations,anditisnotfeasibletoisolatethem together.C.Thecomplexesallusethesamesubstrates,sotheirusemustbemonitored separately.D.Thereactionscatalyzedbythecomplexesarecoupledtooneanother.TheanswertothisquestionisDbecausestudyingthecomplexesalltogetherwould leadtoerroneousresultsbecauseinhibitionofcomplexesIandIIaffectstheactivity ofComplexIII,whichaffectstheactivityofComplexIV.Alargecarbohydrateistaggedwithafluorescentmarkerandplacedinthe extracellularenvironmentaroundamacrophage.Themacrophageingeststhe carbohydrateviaphagocytosis.Whichcellularstructureismostlikelytobe fluorescentlylabeleduponviewingwithalightmicroscopesoonafterphagocytosis?A.Nucleus B.Golgiapparatus C.Lysosome D.Endoplasmicreticulum TheanswertothisquestionisCbecausewhenamacrophageingestsforeign material,thematerialinitiallybecomestrappedinaphagosome.Thephagosome thenfuseswithalysosometoformaphagolysosome.Insidethephagolysosome, enzymesdigesttheforeignobject.Ofthecellstructureslisted,thelabeled carbohydrateismostlikelytobemicroscopicallyvisualizedwithinalysosome (phagolysosome).

Inhibitionofphosphofructokinase-1byATPisanexampleof:

allostericregulation.feedbackinhibition.competitiveinhibition.A.Ionly

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