生物化學英文版題庫與答案

Chapter1Biochemistry:AnEvolvingScience

MatchingQuestions

Usethefollowingtoanswerquestions1-10:

Choosethecorrectanswerfromthelistbelow.Notalloftheanswerswillbeused,

a)uridine

b)true

c)AG

d)thymine

e)AH

f)sugar-phosphateunits

g)covalent

h)Archaea

i)entropy

j)system

k)3

1)2

m)false

1.DNAismadefromthebuildingblocksadenine,guanine,cytosine,and

Ans:d

Section:1.2

2.TheDNAbackboneismadefromrepeating.

Ans:f

Section:1.2

3.ThenumberofhydrogenbondsformedbetweenAandT.

Ans:1

Section:1.2

4.ThenumberofhydrogenbondsformedbetweenGandC.

Ans:k

Section:1.2

5.ThefundamentalgroupsoforganismsincludeEukarya,Bacteria,and

Ans:h

Section:1.1

6.Thestrongestbondsinmolecules:

Ans:g

Section:1.3

7.Hydrogenbondsareusuallystrongerthancovalentbonds(true/false).

Ans:b

Section:1.3

8.Matterwithinadefinedregionofspace.

Ans:j

Section:1.3

9.ForspontaneousreactionstheAGmustbepositive.

Ans:m

Section:1.3

10.Gibbsfreeenergy.

Ans:c

Section:1.3

MultipleChoiceQuestions

11.ThestructureofDNAdescribedbyWatsonandCrickincluded

A)adoublehelix.

B)thesugarphosphatebackbonealignedinthecenterofthehelix.

C)thebasepairsthatarcstackedontheinsideofthedoublehelix.

D)aandb.

E)aandc.

Ans:ESection:1.2

12.WhatdidWatsonandCricksuggesttobesignificantaboutthebasepairingfoundinthehelix?

A)ItallowedtheDNAtotwistinahelix.

B)TheDNAcouldbecircular.

C)Itwasamechanismforcopying.

D)Alloftheabove.

E)Noneoftheabove.

Ans:CSection:1.3

13.Approximatelywhatpercentageofthehumangenomeencodesforproteins?

A)50%

B)90%

C)10%

D)3%

E)Noneoftheabove.

Ans:DSection1.4

14.Whatgivesproteinssuchadominantroleinbiochemistry?

A)thevariationinproteinsizes

B)theabilitytoactasablueprint

C)theirabilitytoself-replicate

D)theirabilitytospontaneouslyfoldintocomplexthree-dimensionalstructures

E)Alloftheabove.

Ans:DSection:1.4

15.Ifthewholechainisusedinanon-overlappingframe,howmanyaminoacidsaredefinedby

thisDNAsequence:ATGTTTGGACTA?

A)fourB)twoC)twelveD)sixE)three

Ans:ASection:1.4

16.Whatisthe[H+]concentrationinaurinesamplethathasapHof6?

A)IO"M

B)IO-*M

C)106M

D)10-l4M

E)8M

Ans:BSection1.3

17.Whichofthefollowingisconsideredasanoncovalentbond?

A)electrostaticinteractionsD)Alloftheabove.

B)hydrogenbondsE)Noneoftheabove.

C)vanderWaalsinteractions

Ans:DSection:1.3

18.Theenergiesforhydrogenbondsareapproximately

A)400kJ/mol.D)200kJ/mol.

B)100-240kJ/mol.E)Noneoftheabove.

C)4-20kJ/mol.

Ans:CSection:1.3

19.Whatpairsofatomsinbasesarcinvolvedinhydrogenbonds?

A)N-HandO一HD)Alloftheabove.

B)N—HandS—HE)Noneoftheabove.

C)O—HandP—O

Ans:ASection:1.3

20.TypicalvandorWaalsenergiesareabout

A)4-20kJ/mol.D)Alloftheabove.

B)2-4kJ/mol.E)Noneoftheabove.

C)200kJ/mol.

Ans:BSection:1.3

21.Whattwopropertiesofwaterareimportantforbiologicalinteractions?

A)thepolarityofwaterD)aandc

B)thedensityofwaterE)bandc

C)thecohesivepropertiesofwater

Ans:DSection:1.3

22.TheFirstLawofThermodynamicsstates

A)diversityistheresultofgradualevolution.

B)thetotalentropyofasystemanditssurroundingsalwaysincreasesforaspontaneous

process.

C)thetotalenergyofasystemanditssurroundingsisconstant.

D)lightisbothparticleandwave.

E)Noneoftheabove.

Ans:CSection:1.3

23.TheSecondLawofThennodynamicsstates

A)thetotalentropyofasystemanditssurroundingsalwaysincreasesforaspontaneous

process.

B)temperatureswillalwaysdecrease.

C)thetotalenergyofasystemanditssurroundingsisconstant.

D)diversityistheresultofgradualevolution.

E)Noneoftheabove.

Ans:ASection:1.3

24.Listatomscommonlyfoundinbiologicalmoleculesthatareoftenhydrogen-bondacceptors.

A)carbonB)oxygenC)nitrogenD)bandcE)Alloftheabove.

Ans:DSection:1.3

25.Enthalpyisdefinedas

A)aspontaneousreaction.D)Alloftheabove.

B)theentropyofthesystem.E)Noneoftheabove.

C)theheatcontentofasystem.

Ans:CSection:1.3

26.IfaparticularreactionhasanegativeAG,isitlikelytooccur?

A)Notunlessenergyisaddedtothesystem.

B)Yes,ifitiscoupledtoanotherreaction.

C)Yes,itisspontaneous.

D)No,itwillneveroccur.

E)Yes,ifittakesplacewithinaconstrainedarea.

Ans:CSection:1.3

27.Whathappenstononpolarmoleculesinwater?

A)Theydissolveindependently.D)Alloftheabove.

B)Theyaggregatetogether.E)Noneoftheabove.

C)Theyprecipitate.

Ans:BSection:1.3

28.Whatisthe[A]/[HA]ratiowhentheweakacidisinasolutiononepHunitaboveitsp/fa?

A)1:1D)2:1

B)1:10E)Noneoftheabove.

C)10:1

Ans:CSection1.3

29.WhydoesDNAdenaturewhenthepHisraisedabove9?

A)Protonsdissociatefromguaninebasesdisruptingthehydrogenbondingtotheother

strand.

B)Protonsbindtoguanineresiduesgivingthemadditionalpositivechargeswhichdisrupt

thehydrogenbondingtotheotherstrand.

C)Protonsbindtofunctionalgroupsthatserveashydrogen-bondacceptors,thusdisrupting

thehydrgogenbondingtotheotherstrand.

D)Protonsdissociatefromthephosphategroupsinthebackbone,whichdisruptsthe

hydrogen-bondingpatternbetweenstrands.

E)Noneoftheabove.

Ans:ASection1.3

30.Stereochemistrycanbeeasilydepictedinasimpleformusing

A)Ball-and-stickmodels.D)Fisherprojections.

B)ribbondiagrams.E)Noneoftheabove.

C)Space-fillingmodels.

Ans:DSection:Appendix

31.WhichofthefollowingistheHenderson-Hasselbachequation?

Ans:ASection1.3

32.WhatarctheprimarychemicalcomponentspresentinaphosphatebufferatpH7.4?

2

A)H3PO4andPOjD)H2PO4-andHPO4*

32

B)H2PO4-andPO4-E)H3PO4andHPO4-

2

C)HPO4-andPOj

Ans:DSection1.3

Short-AnswerQuestions

33.Whataresomeofthemedicalimplicationsofthehumangenomeproject?

Ans:Theobvioususeisindiagnosingdiseaseandindevelopingmethodstotreatandcure

diseases.Physicianswillbeabletoaccountforindividualgeneticdifferencesin

determiningthebestmedicaltreatment.

Section:Introduction

34.WhatisthesignificanceofhydrogenbondinginbiochemicalstructuressuchasDNA?

Ans:Thebondsareweakenoughtobeeasilydisrupted;yetwhenmanyarepresent,they

providethestabilizationnecessaryforlargerstructuressuchasDNA.

Section:1.2

35.Whatadaptationaffectedevolutionarydiversity?

Ans:Alterationofbiochemicalmoleculesandcomponentstonewrolesiskeytodiversityand

evolution.

Section:1.1

36.Describeresonancestructures.

Ans:Resonancestructuresarewaysofwritingcovalentbondsinwhichtwoormorealternate

bondingpatternscanbeachieved.Thisisduetothesharingofelectronsoverseveral

atoms.Commonexamplesarefoundinpeptidebonds,andinsomeofthebases.Benzene

isshowninthetext.

Section:1.3

37.Whatisanelectrostaticinteraction?Giveanexample.

Ans:Itistheattractiveforceoftwooppositelychargedatoms.Salts(suchasNaCl)area

commonexample.

Section:1.3

38.Howiswaterabletobeasolventforsomanybiologicalmolecules?

Ans:Manybiologicalmoleculeshavepolarcharacteristics.Waterisextremelypolarandis

capableofcompetingwithotherpolarmoleculesbyweakeningtheirelectrostaticand

hydrogenbonds.Theoxygencanactasahydrogen-bondacceptor,andthehydrogencan

actasadonor.

Section:1.3

39.WhatistheneteffectofmanyvanderWaalsinteractions?

Ans:Attheinterfaceoftwolargemolecules,thenumerousvanderWaalsinteractionscan

substantiallyaffectandstabilizetheinteraction.

Section:1.3

40.Ifmostproteinsarefoundsurroundedbywaterinthecell,whattypeoffunctionalgroups

wouldyouexpecttofindonthesurfaceofawatersolubleprotein?

Ans:Polarandchargedamino-acidresidueswouldbepresentonthesurfaceoftheprotein.

Section:1.3

41.Howareelectrostaticforcesusedinproteinfolding?

Ans:Theattractionoftwooppositelychargedfunctionalgroupswouldbeoneoftheforces

helpingtoformthethree-dimensionalshapeoftheprotein.

Section:1.3

42.IftheFirstLawofThermodynamicsistrue,howcanbiologicalprocessesbecarriedout?

Ans:Althoughenergycannotbecreatedordestroyed,itcantakeondifferentforms,suchas

heatorchemicalenergy.Thus,theenergycanbestoredaschemicalbondenergy,which

canbeusedtodowork.

Section:1.3

43.HowcanacellexistiftheSecondLawofThermodynamicsistrue?

Ans:Entropyinalocalareacanbedecreased,butonlyattheexpenseofincreasedentropyin

thelargerarea,oruniverse.

Section:1.3

44.Provideasimpleexampleofentropyprocesses.

Ans:Severalexamplescanbeprovided,includingtherandommixtureofatomswhentwo

differentgasesaremixed,orthecreationofwatermoleculesfromenergygained

followingthemixtureofoxygenandhydrogenundercertainconditions.

Section:1.3

45.Whatdoesthisequationmean:

△G=AHSyStem一TASsystem<0?

Ans:Thefreeenergychange(AG)mustbenegativeforareactiontobespontaneous.Only

undertheseconditionscanthetotalentropyincrease.

Section:1.3

46.WhatisthesignificanceofusingAGinbiochemistry?

Ans:Gibbs-freeenergy,alsocalledthefree-energychange,isusedtodescribetheenergetics

ofareaction.Thissymbolisusedtodetermineifparticularreactionswillbespontaneous

orbiologicallyfeasible.

Section:1.3

47.Whatthermodynamicandfree-energychangesparticipateinproteinfolding?

Ans:AcombinationofhydrogenbondsandvanderWaalsforcesaffectenthalpyandthe

entropyassociatedwithhydrophobicinteractions.

Section:1.3

48.Howdohydrophobicinteractionsaidinproteinfolding?

Ans:Hydrophobicinteractioncausessomenonpolaraminoacidstoaggregateandformthe

interioroftheprotein.Thisresultsinanetreleaseofheatandafavorablechangeinthe

systementhalpy.

Section:1.4

49.WhatarctheenthalpyandentropychangesthataccompanytheformationofDNAdouble

helixesfromcomplementarysinglestrandsofDNA?

Ans:Thereisalossofentropyfromthesystembecausetherearefewerdegreesoffreedomin

thedoublehelixascomparedtothesinglestrands.Therefore,heatmustbereleased

whenthetwostrandscombinetoformthedoublehelixsoasnottoviolatetheSecond

LawofThermodynamics.

Section1.3

50.Describetheshapeofmethane.

Ans:Methaneistetrahedralandsp3hybridized,withbondanglesofabout109°.

Section:Appendix

Chapter2ProteinCompositionandStructure

MatchingQuestions

Usethefollowingtoanswerquestions1-10:

Choosethecorrectanswerfromthelistbelow.Notalloftheanswerswillbeused.

a)L-aminoacids

b)water

c)protons

d)Zwitterions

e)secondarystructure

f)tertiarystructure

g)Ramachandran

h)cysteine

i)extracellular

j)histidine

k)proline

1)Sanger

m)D-aminoacids

1Chiraltypeofaminoacidsfoundinproteins.

Ans:a

Section:2.1

2Anothernamefordipolarmolecules.

Ans:d

Section:2.1

3Disulfidebondsarcformedbypairsofwhichaminoacid?

Ans:h

Section:2.1

4TheaminoacidwithapK&nearneutralpH.

Ans:j

Section:2.1

5Whenapeptidebondisfbnned,whatmoleculeisalsomade?

Ans:b

Section:2.2

6Wherearcproteinswithextensivedisulfidelinkslikelytobefound?

Ans:i

Section:2.2

7Thisaminoacidresiduedisruptstheahelixbecauseitssidechaincontainsa

uniqueringstructurethatrestrictsbondrotations.

Ans:k

Section:2.1

8Nameoftheplotthatallowsonetoinvestigatethelikelyorientationofcertain

aminoacidpairs.

Ans:g

Section:2.2

9Thetypeofstructuretowhichahelices,psheets,andturnsarereferred.

Ans:e

Section:2.3

10Theoverallstructureofaproteinisreferredtoas

Ans:f

Section:2.4

FillintheBlankQuestions

11Theaminoacidthatcontainsaweaklyacidic"phenolic”groupis.

Ans:tyrosineSection2.1

12isafibrousproteinandistheprimarycomponentofwoolandhair.

Ans:AkeratinSection2.3

13Everythirdresidueintheproteincollagenis.

Ans:glycineSection2.3

14Disulfidebondsinproteinscanbereducedtofreesulfhydrylgroupsbyreagentssuchas

Ans:pmecaptoethanolSection2.6

15Aproteinisconsideredtobewhenitisconvertedintoarandomlycoiled

structurewithoutitsnormalactivity.

Ans:denaturedSection2.6

16isthemajorfibrousproteinpresentinskin,bone,tendon,cartilage,

andteeth.

Ans:CollagenSection2.3

17Collagencontains,amodifiedaminoacid.

Ans:hydroxyprolineSection2.6

18Agentssuchasandguanidinehydrochloridedenatureproteinsby

disruptingthenoncovalentinteractions.

Ans:ureaSection2.6

19referstothespatialarrangementofsubunitsandthenature

oftheirinteractions

Ans:QuaternarystructureSection2.5

20Thep-sheetstructureoccurswhenthetwostrandsareorientedin

oppositedirections(N—>C).

Ans:antiparallelSection2.3

MultipleChoiceQuestions

21Whatdeterminesaprotein'sfunction?

A)structureD)Noneoftheabove.

B)genesequenceE)Alloftheabove.

C)N-terminalaminoacids

Ans:ASection:Introduction

22Keypropertiesofproteinsinclude

A)awiderangeoffunctionalgroups.

B)anabilitytopossesseitherrigidorflexiblestructuresasdictatedbyfunctional

requirements.

C)theabilitytointeractwithotherproteins.

D)aandb.

E)Alloftheabove.

Ans:ESection:Introduction

23Whatchargedgroup(s)arepresentinglycineatapHof7?

++

A)-NH3B)-COO-C)-NH2D)aandbE)a,b,andc

Ans:DSection:2.1

24AtapHof12,whatchargedgroup(s)arepresentinglycine?

A)-NH3+B)?COCFC)-NH2+D)aandbE)a,b,andc

Ans:BSection:2.1

25InwhatpHrangeiszwitterionicAlaninethepredominatestructure?

A)0-2D)2-4

B)9-14E)2-9

C)8-10

Ans:ESection2.1

26Whichaminoacidscontainreactivealiphatichydroxylgroups?

A)serineandmethionineD)cysteineandmethionine

B)serineandthreonineE)cysteineandthreonine

C)methionineandthreonine

Ans:BSection:2.1

27NamethreeaminoacidsthatarepositivelychargedataneutralpH.

A)lys,arg,andhisD)lys,arg,andpro

B)his,arg,andcysE)arg,glu,andhis

C)cys,arg,andmet

Ans:ASection:2.1

28Inthefollowingpeptide,whichaminoacidistheN-tenninus?

Phe-Ala-Gly-Arg

A)AlaB)PheC)PheandArgD)ArgE)Noneoftheabove.

Ans:BSection:2.2

29Whatistheapproximatemassofaproteincontaining200aminoacids?(Assumethereareno

otherproteinmodifications.)

A)20,000B)11,000C)22,000D)222,000E)Noneoftheabove.

Ans:CSection:2.2

30WhichindividualwonaNobelPrizeforhislandmarkworkinsequencingtheproteininsulin?

A)PaulingB)McClintockC)GilbertD)MaxamE)Sanger

Ans:ESection:2.2

31Whyisthepeptidebondplanar?

A)Bulkysidechainspreventfreerotationaroundthebond.

B)Itcontainspartialdouble-bondcharacter,preventingrotation.

C)HydrogenbondingbetweentheNHandC=Ogroupslimitsmovement.

D)Noneoftheabove.

E)Alloftheabove.

Ans:BSection:2.2

32Theconfigurationofmosta-carbonatomsofaminoacidslinkedinapeptidebondis

A)cis.B)circular.C)parallel.D)trans.E)perpendicular.

Ans:DSection:2.2

33Whatstructure(s)didPaulingandCoreypredictin1951?

A)ahelixB)psheetC)pturnsD)a,b,andcE)aandb

Ans:ESection:2.4

34Whichofthefollowingprotein(s)containexamplesofahelicalcharacter?

A)keratinB)ferritinC)myosinD)tropomyosinE)Alloftheabove.

Ans:ESection:2.4

35WhereareCandPturnsandloopsoftenfound?

A)inahydrophobicpocketD)onthesurfaceofproteins

B)ontheinteriorcleftE)Noneoftheabove.

C)attheproteininterfacewithligand

Ans:DSection:2.3

36Whataresomeofthemodificationsthatproteinsacquire?

A)cleavageandtrimmingoftheproteinD)a,b,andc

B)additionofcarbohydrategroupsE)bandc

C)phosphorylationofcertaingroups

Ans:DSection:2.6

37Whichofthefollowingaminoacidresidueswouldmostlikelybeburiedintheinteriorofa

watersoluble,globularprotein?

A)AspD)Lys

B)SerE)Gin

C)Phe

Ans:CSection2.5

Short-AnswerQuestions

38Howdoesaprotein'saminoacidsequenceinfluencethetertiarystructure?

Ans:Aproteinwillspontaneouslyfoldintoathree-dimensionalstructuredeterminedbythe

aminoacidsequence.

Section:Introduction

39Whatistheadvantageofhaving20differentaminoacidsavailabletoformproteins?

Ans:Theaminoacidsprovidearichdiversityoffunctionalgroups,whichcanindependently

contributetoproteinstructureandfunction.Inaddition,manycanbemodified,

increasingthediversityoffunctionalgroups.

Section:Introduction

40Whatistheadvantageofproteininteractionandassemblywithotherproteins?

Ans:Whenproteinsinteractorassemble,newfunctionsandspecificitybecomeavailable.

Proteininteractionsallownewbindingsitesattheassemblyinterface,aswellas

providingmultifunctionalactivityandspecificity,suchasfoundinpolymerasesand

signaltransduction.

Section:Introduction

41Whatarethethreearomaticaminoacids?

Ans:phenylalanine,tyrosine,andtryptophan

Section:2.1

42Whichaminoacidsidechainsarecapableofionization?

Ans:Theaminoacidsare:Asp,Glu,His,Cys,Tyr,Lys,andArg.

Section:2.1

43Howdoestheproteinbackboneaddtostructuralstability?

Ans:Theproteinbackbonecontainsthepeptidebond,whichhasNHmoleculesandC=O

(ketone)groups.Hydrogen-bondformationbetweenthehydrogenonthenitrogenandthe

oxygensupporttheproteinconformation.

Section:2.2

44Whyarcallthetheoreticalcombinationsofphiandpsinotpossible?

Ans:Sterichindrancesofthesidechainsmakecertaincombinationsandanglesimpossible.

Section:2.2

45Describesomeofthefeaturesofanahelix.

Ans:Theahelixiscoilstabilizedbyintrachainhydrogenbondsbetweenthecarbonyloxygen

ofaresidueandtheamidehydrogenofthefourthresidueaway.Thereare3.6amino

acidsperturn.Thehydrogenbondsarebetweenaminoacidresiduesthathavetwo

interveningresidues.Thus,theseaminoacidresiduesarcfoundonthesamesideofthe

coil.Thehelixisalmostalwaysright-handed,althoughleft-handedhelicesare,intheory,

possible.

Section:2.3

46Whatisthe"hydrophobiceffeef9asitrelatestoproteinstructure?

Ans:Thethree-dimensionalstructureofawatersolubleproteinisstabilizedbythetendencyof

hydrophobicgroupstoassembleintheinteriorofthemolecule.

Section:2.1

47Whatisaproteindomain?

Ans:Adomainisadefinedregionofaprotein.Often,adomainisdefinedbyaparticular

function.

Section:2.4

48Whatarcprions?

Ans:Prionsareproteinsthatcanassume(afterinfectionorbyothercauses)anewprotein

structure,whichisself-propagating.Thediseasehasseveralvariants,andatleastoneis

fataltohumans.

Section:2.6

49IntheribonucleaseexperimentsperformedbyAnfinson,whatwasthesignificanceofthe

presenceofthereducingagentpmercaptoethanol?

Ans:Thereducingagentreducedincorrectlypaireddisulfidebondsallowingthemtoreform

withthecorrectpairinguntilthemoststableconformationoftheproteinhadbeen

obtained.

Section:2.6

50Whatistheadvantageofhavingcertainregionsofpartiallycorrectfoldedregions?

Ans:Ifsomeregionsinteractpreferentially,lendingstabilitytocertainconformationsasthe

proteinfolds,theycanimpacttheoverallstructureoftheprotein.

Section:2.6

Chapter3ExploringProteinsandProteomes

MatchingQuestions

Usethefollowingtoanswerquestions1-10:

Choosethecorrectanswerfromthelistbelow.Notalloftheanswerswillbeused.

a)HPLC

b)specificactivity

c)MALDI-TOFmassspectrum

d)zonalcentrifugation

e)nascent

f)SDS

g)epitope

h)Svedberg

i)immunoglobulin

j)centrifugation

k)overlappeptides

1)affinitychromatography

51Theratioofenzymeactivityrelativetototalproteiniscalled.

Ans:b

Section:3.1

52Thefirststepinproteinpurificationfromahomogenateisusually.

Ans:j

Section:3.1

53Atypeofpurificationthatisbasedontheattractionoftheproteinforaparticular

chemicalgroup.

Ans:1

Section:3.1

54canbeaddedpriortogelelectrophoresistodenaturetheproteins.

Ans:f

Section:3.1

55Sedimentationcoefficientsaredescribedasunits.

Ans:h

Section:3.1

56Proteinswithdifferentsedimentationcoefficientscanbeseparatedby.

Ans:d

Section:3.1

57Inordertosequenceawholeprotein,areused.

Ans:k

Section:3.2

58Thenameusedtodescribetheoriginal,unclcavedprotein.

Ans:e

Section:3.2

59Anothernameforanantibody.

Ans:j

Section:3.3

60Anothernameforanantigenicdeterminant.

Ans:g

Section:3.3

FillintheBlankQuestions

61Proteinscanbeseparatedfromsmallmoleculesandionsthroughasemi-permeablemembrane

by?

Ans:dialysisSection:3.2

62Exclusiongelorgel-filtrationchromatographyseparatesmoleculesonthebasisof

Ans:sizeSection:3.1

63isachemicalreagentthatisoftenusedtodetectthepresenceofamino

acids.

Ans:NinhydrinSection:3.2

64IntheEdmanprocedureforpeptidesequence,phenylisothiocyanateisusedtoselectively

removetheresidueasaPTH-derivative.

Ans:N-terminalSection:3.2

65Disulfidebondsinpeptidesandproteinsarereadilyoxidizedtocysteicacidresiduesby

treatmentwith.

Ans:perfbrmicacidSection:3.2

66MALDI-TOFistheabbreviationfbr.

Ans:Matrix-AssistedLaserDesorptionandIonizationTimeofFli