生物化学复习题Word文件下载.docx
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A.Hbond.B.Hydrophobicinteraction.C.Ionicinteraction.D.covalentlinkage.
6)whichofthefollowingmutationswouldyouexpecttocausethemostdrasticalterationinthefunctionalperformanceofapolypeptidechain?
(assumingthereplacementisn’tattheactivesite)
A.Replacementofglutamatewithlysine.B.Replacementofvalinewithalanine.
C.Replacementofasparticacidwithglutamicacid.D.Replacementoflysinewitharginine.E.Replacementoftyrosinewithphenylalanine.
7)Inducedfit
A.isaconformationalchangebroughtaboutbythebindingofsubstratetoanallostericsite.
B.isalsoknownascooperativebindingandrequiresenzymeswithmorethanonesubunit.
C.isaconformationalchangeevokedbybindingofsubstratetotheactivesiteofanenzyme.
8)thepeptidebondhasallofthefollowingcharacteristicsexcept
A.planarity.B.freedomtorotate.C.polarity.D.greaterstabilityintransconfiguration.E.partialdoublebondcharacter.
9)Intheregulationofanoverallmetabolicsequence,whichofthefollowingreactionsismostlikelytobemodulatedbyallostericeffectors?
A.Anyreactionofthesequence.B.Thelastreactionofthesequence.
C.Theinitialreactionofthesequence.D.Thefastestreactionofthesequence.
E.Theslowestreactionofthesequence.
10)Ligasesareenzymesthatcatalyzewhichofthefollowingtypeofreaction
A.formationofbondswithATPcleavage.B.additiontodoublebonds.
C.hydrolysisreactions.D.transferoffunctionalgroups.E.oxidation-reductionreactions.
11)Inthecaseofanenzymedisplayingasigmoidrelationshipbetween velocityandsubstrateconcentration,itcanbeconcludedthat
A.thebindingofonesubstratemoleculehindersthebinding ofothers.
B.theenzymecontainsonlyonebindingsiteforsubstrate.
C.substratebindsmoreeasilyatlowconcentrationsthanat highconcentrations.
D.theenzymemustcontainatleastfoursubunits.
E.theenzymedisplayscooperativityintermsofsubstrate binding.
12).threeproteins,a,bandc,withisoelectricpointsof8.8,6.8and4.7respectively,areappliedtothetopofadiethylaminoethylcellulosecolumn(anionexchanger)equilibratedwithabufferofph8.0.thesamebufferispassedthroughthecolumnandthesodiumchlorideconcentrationisprogressivelyincreased.thethreeproteinswillappearinthecolumneffluentintheorderof
A.A,B,C.B.B,C,A.C.C,B,A.D.A,C,B.
13).Drawageneralaminoacidandidentifythetwofunctionalgroupscommontoall.(作图题)
aminogroup,carboxylgroup
14)Drawthereactionthatjoinstwoaminoacidstoformapeptidebond.(作图题)
15)Thestructureoftheaminoacidisoleucineis:
(a)Howmanychiralcentersdoesithave?
2
(b)Howmanyopticalisomers?
4
(c)Drawperspectiveformulasforalltheopticalisomersofisoleucine.
16)accordingtothefollowinginformation,tellmethepIvalueofalaine,lysineandglutamicacid.(计算题)
PIofalanineequaltotheaverageof2.34and9.69,or6.02
PIofglutamicacidequaltotheaverageof2.19and4.25,or3.22
PIoflysine,PIequaltotheaverageof8.95and10.79,or9.87
17)judgement:
Amixtureofaminoacidscanbeseparatedonthebasisofpolarity.ifthesolidphasearepolarmaterials,Themostpolaraminoacidgofast.
False,Amixtureofaminoacidscanbeseparatedonthebasisofpolarity.ifthesolidphasearepolarmaterials,Themostpolaraminoacidgoslow,andtheleastaminoacidgofast.
18)Histidinehasthreeionizablefunctionalgroups.Drawthestructureofhistidineineachionizationstate.WhatisthenetchargeofhistidineatpH1,4,8,and12?
ForeachpH,willhistidinemigratetowardtheanode(+)orcathode(-)whenplacedinanelectricfield?
(综合题)
19)Ifthesamplecontain0.4gofNitrogen,tellmetheamountofproteinthatthesamplewillcontain.(计算题)
Answer:
Proteincontain16%Nitrogen.1gN=6.25gprotein,thesamplewillcontain_2.5_gprotein.(0.4X6.25=2.5)
20)judgement:
GlobularProteinsisUsuallywatersoluble,compact,roughlysphericalwithHydrophobicinterior,hydrophilicsurface.Correct
21)majorcomponentsofhairandnailsare:
A.Α-keratinsb.Collagenc.Globularproteins
22)apeptidecontainingmorethanadozenaminoacidsis:
a.dipeptideb.polypeptidec.multimers
23)TheIsoelectricPointofPepsinPepsinofgastricjuice(pH≈1.5)hasapIofabout1.WhatfunctionalgroupsmustbepresentinrelativelylargenumberstogivepepsinsuchalowpI?
Whataminoacidscancontributesuchgroups?
Answer:
Carboxylgroup,Aspartate,Glutamine
24)ThepIofhistoneisveryhigh,about10.8.Whataminoacidsmustbepresentinrelativelylargenumbersinhistone?
InwhatwaydotheseresiduescontributetothestrongbindingofhistonetoDNA?
Lysine,Arginine,HistidineElectrostaticattraction
25)onecancalculatetheapproximatenumberofaminoacidresiduesinasimpleproteincontainingnootherchemicalgroupbydividingitsmolecularweightby-_____.
A.138b.128c.110
26)Whatistheapproximatemolecularweightofaproteincontaining682aminoacidsinasinglepolypeptidechain?
682*110=75020
27)proteincontainonlyaminoacidandnootherchemicalgroupiscalled:
a.simpleproteinb.conjugatedproteinplexprotein
28)TheelectrophoreticmobilityofastandardproteinonanSDSpolyacrylamidegelisrelatedtoitsmolecularweight.comparedwiththepositionstowhichproteinsofknownmolecularweightmigrateinthegel,Estimatingthemwoftheunknownprotein.(log10158489=5.2;
log106309.6=3.8;
log1046418=4.67)(计算题)
Theslopeofthestandardlineis(y2-y1)/(x2-x1)
(5.2-3.8)/(0.08-0.92)=1.4/(-0.84)=-1.6667
Theslopeforunknowny/(0.4-0.92)=y/(-0.52)=-1.6667
Therefore,y=0.866684andthelogofthemolecularweightis3.8+0.866684=4.666684
Themolecularweightistheantilogof4.666684=46418
29)canactwithhighspecificityopeningpeptidebondsonthecarbonylsideofphenylalanine,tryptophanandtyrosine
a.chymotrypsinb.trypsinc.pepsin
30)ASOLUTIONCONTAINEDPROTEINAWITHAPIOF6ANDPROTEINBWHOSEPIWAS9.ATWHICHOFTHEFOLLOWINGPHVALUESWOULDBOTHPROTEINSMIGRATETOTHEANODE(POSITIVE(+)ELECTRODE)?
A.PH4B.PH6C.PH7D.PH9E.PH10
31)APARTICULARAMINOGROUPHASAPKAOF7.5.WHATISTHERATIOOFTHECONCENTRATIONSOFCHARGEDTOUNCHARGEDSPECIESINASOLUTIONATPH6.5?
A.100:
1B.10:
1C.1:
1D.1:
10
32)WHICHOFTHEFOLLOWINGPROPERTIESDOESNOTPERTAINTOPEPTIDEBONDS?
A.THEBONDCANBEHYDROLYZEDBYPROTEASESB.THEBONDCANBEHYDROLYZEDBYSTRONGACIDSATHIGHTEMPERATURESC.THEPEPTIDEBONDISPLANARD.ROTATIONABOUTTHEPEPTIDEBONDISALLOWEDE.THEPEPTIDEBONDDEMONSTRATESELECTRONRESONANCE
33)AllofthefollowingstatementsaboutserumlacticaciddehydrogenasearetrueEXCEPT:
(糖酵解一章内容)
A.itexistsasfivedifferentisoenzymes.B.itconsistsofidenticalsubunits.
C.differentformsoflacticaciddehydrogenaseattackthesamesubstratesbutwithdifferentkineticparametersD.itgivesmultiplebandsuponelectrophoresis.
34)GLUCOSE-6-PHOSPHATEDEHYDROGENASEHASANALTEREDELECTROPHORETICMOBILITYATPH8.6CAUSEDBYTHEMUTATIONOFAVALTOWHICHOFTHEFOLLOWINGAMINOACIDS?
(1.理解)
A.ASNB.GLUC.ILED.METE.SER
1. Whichofthefollowingaremetabolicproductsofpyruvateinhigherorganisms?
A.
Glycerol B.
Lacticacid C.
Acetone D.Acetyl-CoA E.
Ethanol
2.Acetyl-CoA
Aincludesathioesterlinkageaspartofitsstructure.
B,takespartintworeactionsofthecitricacidcycle.
C.canbeproducedonlybybreakdownofsugars.
D.doesnotplayaroleinanymetabolicpathwayotherthanthecitricacidcycle.(answer:
A.Correct!
Thethioesterbondiseasilyhydrolyzed,andthisstructuralfeatureaccountsforthereactivityofacetyl-CoA
B.No.Acetyl-CoAtakespartonlyinthefirstreaction,theonethatproducescitrate.
C.No.Acetyl-CoAisalsoaproductoffattyacidbreakdown(aswellasthebreakdownofsomeaminoacids)
No.Acetyl-CoAisakeyintermediateinanumberofmetabolicpathways.)
3.Regenerationofoxaloacetatefromsuccinyl-CoA
a.doesn’trequireoxidizingagent.b.includeahydrationreaction.c.requireanoxidationfollowedbyreductionofcycleintermediate.d.requireATP.
4.The6-carboncompoundcitricacid
a.isformedbycondensationoftwothree-carbonpyruvatemolecules.
b.isformedfromthereactionofa2carbonacetylgroupandoxaloacetate,whichhas4carbons.
c.iscleavedtoa2-carbonanda4-carboncompound.
d.iscleavedtotwo3-carbonpyruvate.
5.Theconversionofisocitratetoalpha-ketoglutarate,
a.isanoxidativedecarboxylation.b.requirethiaminepyrophosphate(TPP).
c.requirescoenzymeA.d.isthelaststepinthecitricacidcycle.
6.Theconversionofsuccinatetofumarateisuniqueamongthecitricacidcyclereactionsinthatit:
requirelipoicacid(硫辛酸);
involvecleavageofadoublebond;
isadehydrationreaction;
iscatalyzedbyamembrane-boundenzyme.
7.Thecitricacidcycleasawhole:
a.producesacetyl-CoA.b.consumeGT