Test Bank For Principles Of Biochemistry, 4th Edition

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ContentsChapter 1Introduction to Biochemistry1Chapter 2Water10Chapter 3Amino Acids and the Primary Structures of Proteins27Chapter 4Proteins: Three-Dimensional Structure and Function46Chapter 5Properties of Enzymes65Chapter 6Mechanisms of Enzymes85Chapter 7Coenzymes and Vitamins104Chapter 8Carbohydrates119Chapter 9Lipids and Membranes137Chapter 10Introduction to Metabolism153Chapter 11Glycolysis169Chapter 12Gluconeogenesis, The Pentose Phosphate Pathway,and Glycogen Metabolism185Chapter 13The Citric Acid Cycle199Chapter 14Electron Transport and Oxidative Phosphorylation213Chapter 15Photosynthesis227Chapter 16Lipid Metabolism241Chapter 17Amino Acid Metabolism256Chapter 18Nucleotide Metabolism269Chapter 19Nucleic Acids284Chapter 20DNA Replication, Repair, and Recombination300Chapter 21Transcription and RNA Processing315Chapter 22Protein Synthesis330Chapter 23Recombinant DNA Technology348

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Chapter1IntroductiontoBiochemistry1) Whichelementsaccountformorethan97%oftheweightofmostorganisms?A) C,H,N,Mg,O,SB) C,H,N,O,P,SC) C,H,ND) Fe,C,H,O,PE) Ca2+,K+,Na+,Mg2+,Cl-Answer: BPageRef:Section22) ProteinsinbiologicalmembranesmaybeA) porous.B) attachedtothemembranesurface.C) spanthemembrane.D) AlloftheaboveE) BandConlyAnswer: DPageRef:Section33) Whichstatementaboutcelluloseisfalse?A) Itisthemostabundantpolysaccharideinnature.B) Itsmonomersarejoinedbyglycosidicbonds.C) Itispresentinthestemsoffloweringplants.D) Thehydroxylgroupsofneighboringcellulosemoleculesinteracttoformstrong,insolublefibers.E) Itisabranchedpolymerofglucose.Answer: EPageRef:Section31

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4) WhenKeqofareaction=1,thenA) theforwardreactionisfasterthanthereversereaction.B) thereversereactionisfasterthantheforwardreaction.C) theforwardandreversereactionrateconstantsareequal.D) moreproductsareformedthanreactants.E) fewerproductsareformedthanreactants.Answer: CPageRef:Section45) Whichstatementistrueaboutareactionwithanequilibriumconstant,Keq,equalto1000?A) Theforwardrateconstantis1000timesgreaterthanthereverserateconstant.B) Theforwardrateconstantis3timesgreaterthanreverserateconstant.C) Theforwardrateconstantis1000timessmallerthanthereverserateconstant.D) Theforwardrateconstantis3timessmallerthanthereverserateconstant.E) Thereisnotenoughinformationgiventocomparetheforwardandreverserateconstants.Answer: APageRef:Section46) Thestudyoftheenergychangesduringmetabolicreactionsiscalled________.A) bioinformaticsB) metabodynamicsC) thermometricsD) bioenergeticsE) biologicalheatdynamicsAnswer: DPageRef:Section47) Aspontaneouschemicalreactionalwayshasa________change.A) positiveGibbʹsfreeenergyB) negativeGibbʹsfreeenergyC) positiveenthalpyD) negativeenthalpyE) positiveentropyAnswer: BPageRef:Section42

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8) ProkaryotesarevaluabletoolsforbiochemistsbecauseA)E.coliiswell-studiedandtypicalofprokaryotes.B) theycontainasmanygenesaseukaryoticcells.C) manyoftheirchromosomesaresequenced.D) theyarenotverydiverseorganisms.E) AlloftheaboveAnswer: CPageRef:Section69) Whichcellularcomponentcarriesoutoxidationreactions,someofwhichproducehydrogenperoxide?A) peroxisomesB) mitochondriaC) chloroplastsD) lysosomesE) vacuolesAnswer: APageRef:Section810) WhyisitimportantthattheenzymesinlysosomesaremoreactiveatacidicpHthanatneutralpH?A) Sincelysosomesareprimarilyfoundinthestomachacidofmammals,theirpHdependenceallowsformaximumefficiencyforthedigestionoffoodstuffs.B) Itpreventstheirdiffusionoutofthelysosomes.C) Itmaximizestheinteractionwiththeirsubstrateswhicharealwaysbases.D) Itpreventsthemfromaccidentallydegradingthemacromoleculesinthecytosol.E) Itallowsforregulationoftheiruptakebythemitochondria.Answer: DPageRef:Section811) Moleculesfromlivingcellscannotbesynthesizedoutsideoflivingcells.Answer: FALSEPageRef:Section112) Fermentationintheabsenceofcellsdemonstratedthatmetabolicprocesseswerechemicalinnature.Answer: TRUEPageRef:Section13

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13) Enzymesareproteincatalyststhatformanintermediatewithasubstratethatfitsintoit.Answer: TRUEPageRef:Section114) Themodifiedlock-and-keytheoryofenzymeactionproposedbyEmilFischerhasbeencompletelyreplacedbymoremodernideasofcatalysis.Answer: FALSEPageRef:Section115) Enzymesarenotasefficientasmostcatalystsusedinorganicchemistry,sincetheymustfunctionatbodytemperature.Answer: FALSEPageRef:Section116) Bioinformaticshaspermittedrapidadvancesinourunderstandingofstructuralmacromoleculesfromlivingcells.Answer: TRUEPageRef:Section117) TheroleofDNAasthegeneticmaterialwasconfirmedbytransformingStreptococciinexperimentsperformedseveralyearsafterthefamousWatsonandCrickdescriptionofDNAstructure.Answer: FALSEPageRef:Section118) CrickreferredtotheflowofinformationfromnucleicacidtoproteinastheCentralDogma.Answer: TRUEPageRef:Section119) Functionalgroupsdescribeoneormoreportionsoforganiccompoundsfoundinlivingcells.Answer: TRUEPageRef:Section220) Aphosphateestercontainsaphosphatefunctionalgroup.Answer: TRUEPageRef:Section221) Undermostbiologicalconditions,acidgroupsandaminogroupsarefullyprotonated.Answer: FALSEPageRef:Section24

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22) Removalofwaterfromresiduesofamacromoleculeresultsintheformationofthatmacromolecule.Answer: TRUEPageRef:Section323)Mristhemassofamoleculerelativeto1/12themassofanatomofthemostcommonisotopeofcarbon.Answer: TRUEPageRef:Section324) Biochemistsdescribingthemolecularweightofaproteinreallymeantheatomicweightingrams.Answer: FALSEPageRef:Section325) Theabsolutemolecularmassofmacromoleculesisgivenindaltons,where1dalton=1atomicmassunit.Answer: TRUEPageRef:Section326) Apeptidebondisformedbythecondensationofdifferentfunctionalgroupsfromtwoaminoacids.Answer: TRUEPageRef:Section327) Theconformationofaproteinenzymedetermineswhetheritisfunctionalornot.Answer: TRUEPageRef:Section328) Lysozymeisanenzymewithacleftordepressionatitsactivesite.Answer: TRUEPageRef:Section329) TheHaworthprojectionoftheringformofamonosaccharidealwaysshowsaflatplanewithoneedgeprojectingoutofthepage(usingthickerlines).Answer: TRUEPageRef:Section330) SugarswithsixcarbonsaretheonlyonescapableofformingaringstructureasshowninaHaworthprojection.Answer: FALSEPageRef:Section35

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31) ATPcontainsbothphosphoesterandphosphoanhydridelinkages.Answer: TRUEPageRef:Section332) AphosphodiesterlinkageinDNAcontainstwophosphorousatoms.Answer: FALSEPageRef:Section333) Lipidsaggregatetoformbilayersbecausesomelipidmoleculesarehydrophobicandotherlipidmoleculesarehydrophilic.Answer: FALSEPageRef:Section334) Thermodynamicsanditslawsareobeyedbylivingcells.Answer: TRUEPageRef:Section435) Thetendencyofametabolicreactiontoproceedisduetothefreeenergyofboththereactantsandproductsaswellasthechangeinrandomnessofthatreaction.Answer: TRUEPageRef:Section436) Biochemicalreactionsaremorelikelytoproceedifthereactionhasanincreaseinenthalpy(△H)andadecreaseinentropy(△S).Answer: FALSEPageRef:Section437) Allprokaryoticcellsareabout1/10thesizeofanaverageeukaryoticcellorsmaller.Answer: FALSEPageRef:Section538) Allcellshavekeptthesamegeneralpatternsofmetabolism,averysimilargeneticcodeandthesamemonomersorresidues.Answer: TRUEPageRef:Section539) Eukaryotesincludeplants,animalsandbacteria.Answer: FALSEPageRef:Section56

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40) Theonlyreasonphagesarenotconsideredtobecellsisbecausetheydonotcontainaplasmamembrane.Answer: FALSEPageRef:Section641) Diffusionisanadequatemeansofdistributingnutrientsinprokaryoticcytoplasmbecausetheyhavemoresurfaceareathanvolumecomparedtomosteukaryotes.Answer: TRUEPageRef:Section742) Eukaryoticcellsaredistinguishedfromprokaryotesbytheirusuallylargersize,acomplexcytoskeletonandmembrane-boundedorganelles.Answer: TRUEPageRef:Section743) Chloroplastsareorganellesfoundinplants,algaeandsomeprotistsandarethesiteofphotosynthesis.Answer: TRUEPageRef:Section744) TheendoplasmicreticulumisthemajorsiteofRNAsynthesisandthesiteofassemblyofribosomes.Answer: FALSEPageRef:Section845) Thenuclearenvelopeisamembranethatsurroundsthenucleusandiscontinuouswiththeendoplasmicreticulum.Answer: TRUEPageRef:Section846) RibosomesonthesurfaceofroughendoplasmicreticulumarethesiteofATPsynthesis.Answer: FALSEPageRef:Section847) TheGolgiapparatusconsistsofflattened,fluid-filled,membranoussacsandisresponsibleforchemicalmodificationandsortingofsomebiomolecules.Answer: TRUEPageRef:Section848) Mitochondriaarethemainsitesofenergytransductioninaerobiceukaryoticcells.Answer: TRUEPageRef:Section87

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49) ThemitochondriaandGolgiapparatusaretwoorganelleswhichoriginatedfrombacteriaandwereincorporatedintoeukaryoticcellsviasymbiosis.Answer: FALSEPageRef:Section850) Inananimalcell,DNAcanbefoundonlyinthenucleus.Answer: FALSEPageRef:Section851) Actinhasbeenshowntobeoneofthemostevolutionarilyconservedproteins.Itispresentinalleukaryoticcellsandfrequentlyisthemostabundantproteininthecell.Answer: TRUEPageRef:Section852) Themitoticspindlesareformedfrommicrotubuleproteins.Answer: TRUEPageRef:Section853) Thefilamentfibersinthecytoskeletonarecomposedprimarilyofcarbohydratemolecules.Answer: FALSEPageRef:Section854) Thediffusionoflargemoleculessuchasenzymesissignificantlyslowedbythepresenceofthecytoskeleton.Answer: TRUEPageRef:Section855) Ineukaryoticcellslysosomesarespecializeddigestivevesicleswithahighlyacidicinterior.Answer: TRUEPageRef:Section856) Theprocessofcelldivisionthatoccursinthetissuesiscalledmitosis.Answer: TRUEPageRef:Section857) Photosynthesisinvolvescapturingenergyfromlightthatisthenusedtodrivetheformationofcarbohydratesfromcarbondioxideandwater.Answer: TRUEPageRef:Section88

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58) ThechemicalnameforATPisalaninetriphosphate.Answer: FALSEPageRef:Section859) Absolutezeroisequalto0°C.Answer: FALSEPageRef:Appendix60) OneAngstromisequalto1×10-10meters.Answer: TRUEPageRef:Appendix9

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Chapter2Water1) Whichisnotaproperwaytoformahydrogenbond?(ThesymbolʺRʺrepresentsageneralorganicgroup.Thehydrogenbondingisrepresentedbydashedlines.)A) IB) IIC) IIID) IVAnswer: BPageRef:Section12) Whichstatementdoesnotexplainthepolarityofwater?A) Oxygenismoreelectronegativethanhydrogen.B) Watermoleculeshaveabentgeometry(V-shaped).C) Theoxygeninwaterhassp2hybridorbitals.D) Inwaterthehydrogencarriesapartialpositivecharge(δ+).Answer: CPageRef:Section13) Whichsubstancedoyouexpecttobemostsolubleinwater?A) ammonia,NH3B) methane,CH4C) carbondioxide,CO2D) nitrogen,N2Answer: APageRef:Section110

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4) Whatisthemaximumnumberofhydrogenbondsthatonewatermoleculecanhavewithneighboringwatermolecules?A) 1B) 2C) 3D) 4Answer: DPageRef:Section25) Theabundanceofwaterinthecellsandtissueshelpstominimizetemperaturefluctuations.Thisisduetowhatpropertyofwater?A) densityB) viscosityC) specificheatD) boilingpointAnswer: CPageRef:Section26) Compoundsthationizewhendissolvedinwaterarecalled________.A) electrolytesB) polarcompoundsC) hydrophobiccompoundsD) amphipathiccompoundsAnswer: APageRef:Section37) ElectrolytesdissolvereadilyinwaterbecauseA) theyareheldtogetherbyelectrostaticforces.B) theyarehydrophobic.C) watermoleculescanclusteraboutcations.D) watermoleculescanclusteraboutanions.E) watermoleculescanclusteraboutcationsandanions.Answer: EPageRef:Section38) Amoleculeorionissaidtobehydratedwhenit________.A) isneutralizedbywaterB) issurroundedbywatermoleculesC) reactsandformsacovalentbondtowaterD) aggregateswithothermoleculesorionstoformamicelleinwaterAnswer: BPageRef:Section311

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9) Whichwouldyouexpecttobemostsolubleinwater?A) IB) IIC) IIID) IVAnswer: APageRef:Section310) SolutesdiffusemoreslowlyincytoplasmthaninwaterbecauseofA) thehigherviscosityofwater.B) thehigherheatofvaporizationofwater.C) thepresenceofmanycrowdedmoleculesinthecytoplasm.D) theabsenceofchargedmoleculesinsidecells.Answer: CPageRef:Section311) The________pressureisthepressurerequiredtopreventtheflowofsolventthroughasolvent-permeablemembranethatseparatestwosolutionsofdifferentsoluteconcentration.A) hydrostaticB) electromotiveC) osmoticD) partialAnswer: CPageRef:Section312

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12) Whichistrueaboutthesolubilityofelectrolytesinwater?A) Theyareallinsolubleinwater.B) Theyareusuallyonlysparinglysolubleinwater.C) Theyoftenformsuper-saturatedaqueoussolutions.D) Theyreadilydissolveandionizeinwater.Answer: DPageRef:Section313) Whatisthedifferencebetweenaparticlebeinghydratedversusbeingsolvated?A) Ahydratedparticleissurroundedbyashellofwater.Asolvatedmoleculeissurroundedbyashellofsolventmolecules,notnecessarilywater.B) Thetermshydratedandsolvatedmeanexactlythesamething.C) Ahydratedparticlehasreactedwithhydrogen.Asolvatedparticleisdissolvedinasolvent.D) Thewordhydratedisusedonlywhenthesoluteisanelectrolyte.Answer: APageRef:Section314) TheosmoticpressureofanaqueoussolutiondependsonA) thechemicalnatureofthesolute.B) themolarconcentrationofsolute.C) thehydrophobiceffectofthesolute.D) Alloftheabove.E) Noneoftheabove.Answer: BPageRef:Section315) Theosmoticpressureofa0.010Msucrose(C12H22O11)solutionat25°Cis0.24atm.Howdoestheosmoticpressureofa0.010Mglucose(C6H12O6)solutionat25°Ccomparetothis?Notethatneithersoluteisvolatileorionizable.A) Theglucosesolutionhasalowerosmoticpressurebecauseitsmolarmassislowerthansucrose.B) Theglucosesolutionhasahigherosmoticpressurebecauseitsmolarmassislowerthansucrose.C) Theosmoticpressuresareequalbecausethesolutionshavethesamemolarconcentration.D) Nothingcanbesaidabouttheosmoticpressureoftheglucosesolutionwithoutmoreinformation.Answer: CPageRef:Section313

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16) Oilandwaterdonotformasolutiondueto________.A) thehydrophobiceffectB) theinabilityofoiltohydrogenbondwithwaterC) thenonpolarityofoilD) Alloftheabove(A-C)E) AandConlyAnswer: DPageRef:Section417) Moleculesthatarebothhydrophobicandhydrophilicare________.A) amphipathicB) amphotericC) bipolarD) notpossibleAnswer: APageRef:Section418) Whichmoleculeorionbelowisamphipathic?A) H2NCH2COOH(glycine)B) H2OC) CH3(CH2)14COO-D) CH3CH2CH2CH2CH3Answer: CPageRef:Section419) Whichstatementexplainsthecleaningactionofsoapongreasydishes?A) Thesoapchangesthewater-solubilityofthegreasesothatitiseasilydissolvedbythewater.B) Thegreaseistrappedinsidethehydrophobicinteriorofmicellesmadeofsoapmolecules.C) Thesoapchemicallybreaksdownthegreaseintosmaller,morewater-solublemolecules.D) Thesoaphydratesthegreasewithitspolarheadgroupsandholdsitinsuspension.Answer: BPageRef:Section420) Someionssuchasthiocyanatethatarepoorlysolvatedinwaterandcanenhancethesolubilityofnonpolarcompoundsinwaterbydisorderingthewatermoleculesarecalled________.A) azeotropesB) hydrophobicionsC) zeolytesD) chaotropesAnswer: DPageRef:Section414

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21) WhichofthefollowingisNOTaʺweakʺinteraction?A) hydrogenbondsB) vanderWaalsforcesC) disulfidebondsD) ionicinteractionsE) hydrophobicinteractionsAnswer: CPageRef:Section522) Whichofthefollowingweakinteractionsisnotanelectrostaticinteraction?A) hydrogenbondsB) charge-chargeinteractionsC) hydrophobicinteractionsD) vanderWaalsforcesAnswer: CPageRef:Section523) Whichofthesenoncovalentforcesinbiologicalsystemsisusuallythestrongest?A) hydrogenbondsB) LondondispersionforcesC) hydrophobicinteractionsD) vanderWaalsforcesAnswer: APageRef:Section524) Hydrogenbondscanoccurwhenhydrogeniscovalentlybondedtoatomslikenitrogenandoxygen.Whatpropertyofnitrogenandoxygenisimportantforthis?A) atomicmassB) ionizabilityC) hydrophobicityD) electronegativityAnswer: DPageRef:Section525) Attractionsofoppositelychargedfunctionalgroupsofproteinsaresometimescalled________.A) saltbridgesorionpairingB) disulfidebridgesC) LondonbridgesD) hydrophilicbridgesAnswer: APageRef:Section515

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26) Whichistrueabouthydrogenbondingforbiologicalmolecules?A) Hydrogenbondsarestrongenoughtoconferstructuralstability,forexampleinDNA.B) Hydrogenbondsareweakenoughtobeeasilybroken(weakerthancovalentbonds).C) Theycontributetothewatersolubilityofmanymacromolecules.D) AlloftheaboveAnswer: DPageRef:Section527) LondondispersionforcesareattractiveforcesthatariseduetoA) infinitesimaldipolesgeneratedbytheconstantrandommotionofelectrons.B) permanentdipolesofmoleculescontainingcovalentbondsbetweenatomsofverydifferentelectronegativities.C) thehydrophobiceffect.D) ionpairingbetweenoppositelychargedfunctionalgroups.Answer: APageRef:Section528) TheaggregationofnonpolarmoleculesorgroupsinwateristhermodynamicallyduetotheA) increasedentropyofthenonpolarmoleculeswhentheyassociate.B) decreasedenthalpyofthesystem.C) increasedentropyofthewatermolecules.D) verystrongvanderWaalsforcesamongthenonpolarmoleculesorgroups.Answer: CPageRef:Section529) WaterclusteredaboutnonpolarmoleculescontributetohydrophobicinteractionsbecauseA) Theirnumberisminimizedtoincreasethetotalentropyofwater.B) Nonpolarmoleculesaremorehighlyorganizedthanpolarmolecules.C) Watermoleculesinthecellaremoreorganizedintheregionsawayfromthenonpolarmolecule.D) AlloftheaboveE) BandCAnswer: APageRef:Section516

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30) ThethreedimensionalstructureofmostproteinsislargelydeterminedbyA) otherproteinswhichfoldthem.B) weaknoncovalentinteractions.C) denaturation.D) hydrogenbonds.E) AlloftheaboveAnswer: BPageRef:Section531) TheoxygenatomofwaterisnucleophilicbecauseA) ithasanegativeoxidationnumber.B) itcarriesapartialpositivecharge.C) ithastwounsharedpairofelectrons.D) itseekselectron-richmolecules.E) AlloftheaboveAnswer: CPageRef:Section632) Waterisanucleophile,yetitdoesnotusuallyhydrolyzemacromoleculesincellsbecauseA) covalentbondslinkingmacromoleculesubunitsarestableatcellpH.B) covalentbondslinkingmacromoleculesubunitsarestableatcelltemperature.C) theconcentrationofwaterismuchtoosmallincells.D) AandBAnswer: DPageRef:Section633) EnzymeswhichcondensesubunitsofmacromoleculesduringtheirsynthesisusuallyA) transferanacylorcarbonylgrouptoanelectrophile.B) excludewaterfromtheactivesite.C) containinhibitorsofhydrolases.D) arecatalyzingthermodynamicallyfavoredreactions.E) AlloftheaboveAnswer: BPageRef:Section617

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34) Theion-productconstantforwater,Kw,isA) 1x10-7M2.B) 1x10-7M.C) 1x10-14M2.D) 1x10-14M.Answer: CPageRef:Section735) Inpurewaterhydroniumionsareformedby________attackofoxygenonaprotoninanadjacentwatermolecule.A) ionicB) nucleophilicC) electrophilicD) covalentAnswer: BPageRef:Section736) PurewaterhasaconcentrationofA) 18g/ml.B) 1g/ml.C) 1000g/ml.D) 55M.Answer: DPageRef:Section737) Whichstatementbestcharacterizesthedistributionofchargeinthehydroniumion,H3O+?A) Thepositivechargeisdistributedoveralloftheatomsintheion.B) Thepositivechargeislocalizedonlyontheoxygenatom.C) Thepositivechargeisdistributedbetweenthethreehydrogenatomsonly.D) Thepositivechargeislocalizedononlyoneofthehydrogenatoms.Answer: APageRef:Section738) Whichstatementbelowistrueabouttherelativelifetimeofahydrogenbond,comparedtotherateofwaterʹsionizationtohydroxideionsandhydroniumions?A) Thestrengthofhydrogenbondingmakesitsdissociationmuchslowerthantheionizationofwater.B) Therateofdissociationofahydrogenbondisthesameorderofmagnitudeastherateofionizationofwater.C) Thetworatesarelinkedinsuchawaythatthemorethewaterisionized,thestrongerandlongerlastinghydrogenbondingwillbe.D) Thelifetimeofawatermoleculebeforeitisionizedisabout109greaterthanthelifetimeofahydrogenbond.Answer: DPageRef:Section718

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39) Theself-ionizationofwateris________.A) aunimoleculardissociationofasinglewatermoleculetoH+andOH-B) abiomolecularreactionbetweentwowatermoleculestoyieldH3O+andOH-C) aresultofhydrophobicinteractionsD) atermolecularreactioninvolvingthesimultaneouscollisionofH2O,H+andOH-Answer: BPageRef:Section740) Howdoestheion-productofwater,Kw,relatetotheequilibriumconstant,Keq,forthedissociationreactionofwater?A) KwisfoundbymultiplyingKeqbytheconcentrationofwater.B) KwjustanothersymbolforKeq,sotheyareequal.C) KwisfoundbydividingKeqbytheidealgasconstant.D) KwisfoundbymultiplyingKeqbytheconcentrationsofhydroniumionandhydroxideion.Answer: APageRef:Section741) Asolutioncontaining10-8MHCland10-8MaceticacidcontainsH+whichissuppliedmostlybyA) thestrongacid.B) theweakacid.C) boththestrongandtheweakacids.D) water.E) AlloftheaboveAnswer: DPageRef:Section842) BasicsolutionsformwhenchemicalsaredissolvedinwaterandremoveA) OH-.B) H+.C) Na+.D) AandBE) A,BandCAnswer: BPageRef:Section819

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43) ThepHofa10-4MsolutionofHClisA) 3.B) 3.5.C) 4.D) 4.5.E) greaterthan4.5.Answer: CPageRef:Section844) ComparesolutionAwithpH=4tosolutionBwithpH=6.A) TheconcentrationofhydroniumioninsolutionAistwicethatinsolutionB.B) SolutionAhasgreaterbufferingcapacitythansolutionB.C) TheconcentrationofhydroniumioninsolutionAis100timesthatinsolutionB.D) ThehydroxideconcentrationsareequalinthetwosolutionssincepHonlymeasurestheconcentrationofH+.Answer: CPageRef:Section845) IfhumanbloodisnotmaintainedatclosetopH=7.4,apersoncandevelopA) acidosis.B) alkalosis.C) diabetes.D) BothAandBE) NoneoftheaboveAnswer: DPageRef:Section846) TheHenderson-HasselbalchequationcanbeusedtocalculateA) thepHofasolutionofanorganicacid.B) theamountofsaltandacidtoaddtoformaspecificbuffer.C) thepKaofaweakacid.D) AlloftheaboveE) AandConlyAnswer: DPageRef:Section920

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47) Theratiooftheconcentrationofa________over________describestheproportionsofformsofaweakacidnecessarytosatisfytheHenderson-Hasselbalchequation.A) conjugateacid;conjugatebaseB) conjugatebase;conjugateacidC) protondonor;protonacceptorD) protonacceptor;protondonorE) BandDAnswer: EPageRef:Section948) AtthemidpointofatitrationcurveA) theconcentrationofaconjugatebaseisequaltotheconcentrationofaconjugateacidB) thepHequalsthepKaC) theabilityofthesolutiontobufferisbestD) AlloftheaboveE) AandBonlyAnswer: DPageRef:Section949) Histidinecontainsanimidazolegroupwhichistitratable.AhistidinebuffercanbepreparedusingA) NaOHandhistidine.B) NaOHandimidazoliumion.C) imidazoliumionandimidazole(conjugatebase).D) HClandimidazole.E) AlloftheaboveAnswer: EPageRef:Section950) TheimidazoliumionhasapKa=7.0.ImidazoliumbufferscanbepreparedforpHvaluesofA) 6.5to7.5.B) 6.1to7.1.C) 5.5to8.5.D) 6.0to8.0.E) 6.0to7.5.Answer: DPageRef:Section921

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51) SinceHClisastrongaciditsvalueofKais________.A) effectivelyequaltoinfinityB) equaltoKwC) zeroD) dependentontheconcentrationofHClAnswer: APageRef:Section952) ForaweakacidwithapKa=6.5,theeffectivebufferingrangeisusuallyconsideredtobeA) pH6topH7.B) pH6.4topH6.6.C) pH5.5topH7.5.D) dependentonthemolarityoftheacid.E) BandCAnswer: CPageRef:Section1053) BloodpHisprimarilyregulatedbyA) aproteinbuffersystem.B) thecarbondioxide-carbonicacid-bicarbonatebuffersystem.C) thephosphatebufferingsystem.D) carbonicacid(H2CO3).E) BandCAnswer: BPageRef:Section1054) IntracellularbuffersincludeA) proteins.B) inorganicphosphate.C) hemoglobin.D) BothAandBE) A,BandCAnswer: DPageRef:Section1022

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55) pKavaluesofphosphoricacidare2.2,7.2and12.7.AphosphatebufferofpH=7.4canbepreparedusingA) H2PO4-andHPO42-.B) HPO42-andPO43-.C) H3PO4andHCl.D) NoneoftheaboveAnswer: APageRef:Section1056) AceticacidhasapKaof4.8.Howmanymillilitersof0.2Maceticacidand0.1Msodiumacetatearerequiredtoprepare1literof0.1MbuffersolutionhavingapHof4.8?A) 500mlaceticacidand500mlsodiumacetateB) 250mlaceticacidand250mlsodiumacetate,then500mlwaterC) 250mlaceticacidand500mlsodiumacetate,then250mlwaterD) 500mlaceticacidand250mlsodiumacetate,then250mlwaterAnswer: BPageRef:Section1057) ThepHofhumanbloodismaintainedat7.4byA) bufferingproteins.B) carbondioxide-carbonicacidbuffersystems.C) abicarbonatebuffersystem.D) BandCE) A,BandCAnswer: DPageRef:Section1058) Thesolubilityruleʺlikedissolveslikeʺrefersprimarilytosimilaritiesinamphipathicnaturebetweenthesoluteandsolvent.Answer: FALSEPageRef:Section159) Thehydrogenbondingbetweenwatermoleculesinicegiveswateranunusuallylowmeltingpointcomparedtoothermoleculesofsimilarsizeandmolecularweightthatcannotformhydrogenbonds.Answer: FALSEPageRef:Section260) Thewatersolubilityofalcoholswithasinglehydroxylgroupincreasesasafunctionofmolecularweight.Answer: FALSEPageRef:Section323

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61) Ahydratedpotassiumionissurroundedbyashellofwatermoleculesorientedprimarilywiththeiroxygenatomstowardthepotassiumion.Answer: TRUEPageRef:Section362) Inthedetergent,sodiumdodecylsulfate,thesulfategroupsareveryhydrophobic.Answer: FALSEPageRef:Section463) VanderWaalsforcesareverystronglyrepulsiveatshortnucleardistancesandveryweakatlonginternucleardistances.Answer: TRUEPageRef:Section564) Thecombinedeffectofmanyweaknoncovalentinteractionscanbeverysignificantindeterminingfactorssuchasthree-dimensionalstructureforlargebiologicalmolecules.Answer: TRUEPageRef:Section565) Watermoleculesthatsurroundalesspolarmoleculeinsolutionareimmobileandordered.Answer: TRUEPageRef:Section566) ThestrengthofvanderWaalsforcesbetweentwomoleculeschangesasthedistancebetweenthemchanges.Answer: TRUEPageRef:Section567) TheattractiveforcebetweentwoatomsismaximizedwhentheyareseparatedbythesumoftheirvanderWaalsradii.Answer: TRUEPageRef:Section568) Saltbridgesareoftenfoundonthesurfacesofproteinswheretheyarestabilizedbywater.Answer: FALSEPageRef:Section569) Hydrogenbondsintheinteriorofaproteinorothermacromoleculearestrongerthanthoseontheexterior.Answer: FALSEPageRef:Section524

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70) Micellesarestabilizedinwaterbyinteractionsofnonpolarmoleculeswitheachother.Answer: TRUEPageRef:Section571) Hydrophobicinteractionsaresometimescalledʺbondsʺ,becauseeachoneisasstrongasacovalentbond.Answer: FALSEPageRef:Section572) Proteinsdissolvedinwatercanbehydrolyzedbynucleophilicattackfromthewatermolecules.Answer: TRUEPageRef:Section673) Anintermediateformedbytheenzymeglutaminesynthetase,gamma-glutamylphosphate,israpidlyhydrolyzedbywateriftheenzymeisnotaroundtoprotectit.Answer: TRUEPageRef:Section674) Whenacidisaddedtopurewater,Kw,theion-productconstantofwater,changes.Answer: FALSEPageRef:Section775) Theequilibriumconstantofwater(Keq)istheratethatdissociationofthemoleculeoccursatroomtemperature.Answer: FALSEPageRef:Section776) TheH+(orH3O+)incellsisthesameconcentrationasthatofundissociatedwater.Answer: FALSEPageRef:Section877) Hyperventilationcanresultinalkalosisbecausethereisexcessivelossofcarbondioxideand,thereforealossofcarbonicacid.Answer: TRUEPageRef:Section878) SincethepKaofaceticacidis4.8,itcanbeusedtoprepareabuffertomaintainphysiologicalpH.Answer: FALSEPageRef:Section925

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79) ThebufferingcapacityofaweakacidanditsconjugatebaseisstrongestwhenthepH=pKa.Answer: TRUEPageRef:Section1080) Syntheticcompoundsusedasbuffersarenotasvaluableforexperimentsasnaturallyoccurringcompoundsusedasbuffers.Answer: FALSEPageRef:Section1026

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Chapter3AminoAcidsandthePrimaryStructuresofProteins1) AminoacidsarenamedthatbecauseeachoneA) isauniquecarboxylicacid.B) hasastandardconfiguration.C) isacarboxylderivativeofanamideacid.D) isanaminoderivativeofacarboxylicacid.Answer: DPageRef:Section12) AminoacidsfoundinmeteoritesandnearstarsareA) Disomersonly.B) Lisomersonly.C) BothDandLisomers.D) notisomers.Answer: CPageRef:Section13) ThelastcommonancestorofmodernorganismsmusthaveusedA) bothDandLaminoacids.B) Daminoacids.C) Laminoacids.D) eitherDorLaminoacids.Answer: CPageRef:Section14) IftheRgroupofanaminoacidis-CH3,thenthenameofthiscompoundisA) methylaminoacid.B) 2-aminopropanoicacid.C) alanine.D) AlloftheaboveE) BandCAnswer: EPageRef:Section127

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5) Aminoacidswithnon-ionizablesidechainsarezwitterionswhentheyare________.A) inanysolutionB) atphysiologicalpH,pH=7.4C) inacidicsolutionsonlyD) inalkalinesolutionsonlyE) AlloftheaboveAnswer: BPageRef:Section16) GlycineisnotastereoisomerbecauseA) ithasnochiralcarbon.B) itdoesnotformenantiomers.C) itdoesnotexistintwonon-superimposablemirror-imageforms.D) AlloftheaboveE) AandBonlyAnswer: DPageRef:Section17) AnaminoacidwithtwochiralcarbonatomsA) isunstable.B) canexistin4formsallofwhicharesuperimposable.C) canformthreepossiblestereoisomers.D) canformfourpossiblestereoisomers.E) canformfivepossiblestereoisomers.Answer: DPageRef:Section18) TheRSsystemofnomenclaturedescribesA) aminoacidsnoteasilydescribedbytheDLsystem.B) thewaytheRgroupsarearranged.C) thechiralcarboncentersofaminoacids.D) thestrengthofthechemicalgroupsinaminoacids.Answer: CPageRef:Section128

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9) TheRgroupofanaminoaciddeterminesifitisA) hyrophilicorhydrophobic.B) polarornonpolar.C) chargedoruncharged.D) anacidorabase.E) AlloftheaboveAnswer: EPageRef:Section110) Prolineisdistinctamongthe20commonlyfoundaminoacidsbecauseA) itisaringcompound.B) itishydrophilicandionic.C) thenitrogenoftheaminogroupisinaring.D) thecarbonofthecarboxylgroupisinaring.E) ithaslittleeffectonproteinstructure.Answer: CPageRef:Section211) TyrosineandtryptophanarelesshydrophobicthanphenylalaninebecauseA) phenylalaninehasanindolegroup.B) phenylalaninehasnopolargroupinthesidechain.C) phenylalanineisaphenol.D) tyrosineandtryptophanhavesmallerRgroups.E) AlloftheaboveAnswer: BPageRef:Section212) Ultraviolet(UV)lightcanbeusedtoestimateproteinsolutionconcentrationsbecauseA) phenylalanineabsorbsat260nm.B) alltheaminoacidsabsorbUVlight.C) aromaticaminoacidsabsorbat280nm.D) tryptophanandtyrosineabsorbat280nm.E) AlloftheaboveAnswer: DPageRef:Section229

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