生化英文习题Word格式.docx
- 文档编号:19174621
- 上传时间:2023-01-04
- 格式:DOCX
- 页数:25
- 大小:7.54MB
生化英文习题Word格式.docx
《生化英文习题Word格式.docx》由会员分享,可在线阅读,更多相关《生化英文习题Word格式.docx(25页珍藏版)》请在冰豆网上搜索。
(Allsequencesarewrittenaccordingtostandardconvention.)
A.CTAGATG
B.GTAGATC
C.GAUCUAC
D.CUAGAUG
E.GUAGAUC
3.Afour-year-oldchildwhobecomeseasilytiredandhastroublewalkingisdiagnosedwithDuchennemusculardystrophy,anX-linkedrecessivedisorder.Geneticanalysisshowsthatthepatient’sgeneforthemuscleproteindystrophincontainsamutationinitspromoterregion.Whatwouldbethemostlikelyeffectofthismutation?
A.Initialtionofdystrophintranscriptionwillbedeficient.
B.Terminationofdystrophintranscriptionwillbedeficient.
C.CappingofdystrophinmRNAwillbedefective.
D.SplicingofdystrophinmRNAwillbedefective.
E.TailingofdystrophinmRNAwillbedefective.
Answer
E.thetwoDNAstrandsarecomplementarytoeachother,withAbase-pairedwithT,andGbasepairedwithC.So,forexample,the20A’sonthefirststrandwouldbepairedwith20T’sonthesecondstrand,the25G’sonthefirststrandwouldbepairedwith25C’sonthesecondstrand,andsoforth.Whenthesearealladdedtogether,thecorrectnumbersofeachbaseareindicatedinchoiceG.Noticethat,inthecorrectanswer,A=TandG=C
E.Allsequencesarewritteninthestandardconvention(5’-3’).TheRNAproducthasasequencethatiscomplementarytothesequenceofthetemplatestrandofDNA.Uracil(U)isfoundinRNAinplaceofthethymine(T)inDNA.Thus,theDNAtemplate5’-GATCTAC-3’wouldproducetheRNAproduct3’-CUAGAUG-5’or,writtencorrectlyinthestandarddirection,5’-GUAGAUC-3’.
A.MutationsinthepromoterpreventformationoftheRNApolymeraseIItranscriptioncomplex,andtheinitationofmRNAsynthesiswillbegreatlydecreased.AdeficiencyofdystrophinmRNAwillresultinadeficiencyintheprocductionofthedystrophinprotein,
Whichoneofthefollowingcorredtlypairsanaminoacidwithavalidchemicalcharacteristic?
A.Glutamine:
Containsahydroxylgroupintissidechain
B.Serine:
Canformdisulfidebonds
C.Cysteine:
Containsthesmallestsidechain
D.Isoleucine:
isnearlyalwaysfoundburiedinthecenterofproteins
E.Glycine:
Containsanamindegroupinitssidechain
Whichoneofthefollowingstatementsconcerningglutamineiscorrect?
A.Containsthreetitratalbegroups
B.Isclassifiedasanacidicaminoacid
C.Containsanamidegroup
D.HasEasitsone-lettersymbol
E.Migratestothecathode(negativeelectrode)duringelectrophoresisatpH7.0
Apeptidebond:
A.hasapartialdouble-bondcharacter.
B.isionizedatphysiologicpH
C.iscleavedbyagentsthatdenatureproteins,suchasorganicsolventsanhighconcentrationsofurea
D.isstaletoheatinginstrongacids
E.occursmostcommonlyinthecisconfiguration.
Whichoneofthefollowingstatementsiscorrect?
A.Theα-helixcanbecomposedofmorethanonepolypeptidechain.
B.β-sheetsexistonlyintheantiparallelform.
C.β-Bendsoftencontainproline.
D.Motifsareatypeofsecondarystructure.
E.Theα-helixisstabilizedprimarilybyionicinteractionsbetweenthesidechainsofaminoacids.
D.Inproteinsfoundinaqueoussolutions,thesidechainsofthenonpolaraminoacids,suchisoleucine,tendtoclustertogetherintheinterioroftheprotein.Glutaminecontainsanamideinitssidechain.Serineandthreoninecontainahydroxylgroupintheirsidechain.Cysteinecanformdisulfidebonds.Glycinecontainsthesmallestsidechain.
C.Glutaminecontainstwotitratablegroups,α-carboxylandα-amino.Glutamineisapolar,neutralaminoacidthatshowslittleelectrophoreticmigrationatpH7.0.Thesymbolforglutamineis“Q”.
A.thepeptidebondhasapartialdouble-bondcharacter.Unlikeitscomponents–theα-aminoandα-carboxylgroups–thecomponentsofthepeptidebonddonotacceptorgiveoffprotons.Thepeptidebondisnotcleavedbyorganicsolventsorurea,butislabiletostrongacids.Itisusuallyinthetransconfiguration
C.β-bendsoftencontainproline,whichprovidesakink.Theα-helixdiffersfromtheβ-sheetinthatitalwaysinvolvesthecoilingofasinglepolypeptidechain.Theβ-sheetoccursinbothparallelandantiparallelforms.Motifsareelementsoftertiarystructure.Theα-helixisstabilizedprimarilybyhydrogenbondsbetweenthe–C=Oand–NH-groupsofpeptidebonds.
Whichoneofthefollowingstatementsaboutproteinstructureiscorrect?
A.Proteinsconsistingofonepolypeptidecanhavequaternarystructure.
B.Theformationofadisulfidebondinaproteinrequiresthatthetwoparticipatingcysteineresiduesbeadjacenttoeachotherintheprimarysequenceoftheprotein.
C.Thestbilityofquaternarystructureinproteinsismainlyaresultofcovalentbondsamongthesubunits.
D.thedenaturationofproteinsalwaysleadstoirreversiblelossofsecondaryandtertiarystructure.
E.Theinformationrequiredforthecorrectfoldingofaproteiniscontainedinthespecificsequenceofaminoacidsalongthepolypeptidechain.
An80-year-oldmanpresentedwithimpairmentofhigherintellecutualfunctionandalterationsinmoodandbehavior.Hisfamilyreprotedprogressivedisorientationandmemorylossoverthelastsixmonths.Thereisnofamilyhistoryofdementia.ThepatientwastentativelydiagnosedwithAlzeheimerdisease.Whichoneofthefollowingbestdescribesthedisease?
A.Itisassociatedwithβ-amyloid----anabnormalproteinwithanalteredaminoacidsequence.
B.Itresultsfromaccumulationofdenaturedproteinsthathaverandomconformations.
C.Itisassociatedwiththeaccumulationofamyloidprecursorprotein.
D.Itisassociatedwiththeaccumulationofamyloidpeptideaggregates.
E.Itisanenvironmentallyproduceddiseaseuninfluencedbythegeneticsoftheindividual.
Acompetitiveinhibitorofanenzyme:
A.increasesKmwithoutaffectingVmax
B.dncreasesKmwithoutaffectingVmax
C.increasesVmaxwithoutaffectingKm
D.dncreasesVmaxwithoutaffectingKm
E.dncreasesbothKmandVmax
E.Thecorrectfoldingofaproteinisguidedbyspecificinteractionsamongthesidechainsoftheamninacidresiduesofapolypeptidechain.Thetwocysteineresiduesthatreacttoformthedisulfidebondmaybeafreatdistaqnceapartintheprimarystructure(oronseparatepolypeptides),butarebroughtintocloseproximitybythethree-dimensionalfoldingofthepolypeptidechain.Denaturationmayeitherbereversibleorirreversible.Quaternarystructurerequiresmorethanonepolypeptidechain.Thesechainsassociatethroughnoncovalentinteractions.
D.Alzheimerdiseaseisassociatedwithlong,fibrillarproteinassembliesconsistingofβ-pleatedsheetsfoundinthebrainandelsewhere.Thediseaseisassociatedwithabnormalprocessingofanormalprotein.Theaccumulatedalteredproteinoccursinaβ-pleatedsheetconfigurationthatisneurotoxic.TheAβamyloidthatisdepositedinthebraininAlzheimerdiseaseisderivedbyproteolyticcleavagesfromthelargeramyloidprecursorprotein----asingletransmembraneproteinexpressedonthecellsurfaceinthebrainanothertissues.MostcasesofAlzheimerdiseasearesporadic,althoughatleastfivetotenpercentofcasesarefamilial.
A.Inthepresenceofacompetitiveinhibitor,anenzymeappearstohavealoweraffinityforsubstrate,butasthesubstratelevelisincreased,theobservedvelocityapproachesVm.
Whichoneofthefollowingstatementsconcerningthebingdingofoxygenbyhemoglobiniscorrect?
A.TheBohreffectresultsinaloweraffinityforoxygenathigherpHvalues.
B.Carbondioxideincreasestheoxygenaffinityofhemoglobinbybindingtotheaminoterminalgroupsofthepolypeptidechains.
C.Theoxygenaffinityofhemoglobinincreasesasthepercentsaturationincreases.
D.Thehemoglobintetramerbindsfourmoleculesof2,3-BPG.
E.Oxyhemoglobinanddeoxyhemoglobinhavethesameaffinityforprotons(H+)
TheMichaelis’constant,Km,is:
A.numericallyequlto1/2Vmax
B.dependentontheenzymeconcentration
C.independentofpH
D.numericallyequaltothesubstrateconcentrationthargiveshalf-maximalvelocity
E.increasedinthepresenceofanoncompetitiveinhibitors
Whichoneofthefollowingstatementsconcerningthecomponentsoftheelectrontransportchainiscorrect?
A.Allofthecomponentsoftheelectrontransportchainarepresentinlarge,multisubunitproteincomplexesembeddedintheinnermitochondrialmembrane.
B.OxygendirectlyoxidizescytochromeC.
C.SuccinatedehydrogenasedirectlyreducescytochromeC.
D.TheelecrontransportchaincontainssomepolypeptidechainscodedforbythenuclearDNAandcomecodedforbymtDNA
E.Cyanideinhibitselectronfolw,butnotprotonpumpingorATPsynthesis.
C.Thebindingofoxygenatonehemegroupincreasestheoxygenaffinityoftheremaininghemegroupsinthesamemolecule.CarbondioxidedecreasesoxygenaffinitybecauseitlowersthepH;
alsobingdingofcarbondioxidestabilizesthetaut,deoxyform.Hemoglobinbindsonemoleculeof2,3-BPG.Deoxyhemoglobinhasagreateraffinityforprotonsand,therefor,isaweakeracid.
D.RememberKmhasthedimensionsofconcentrationandisacharacteristicofanenzymeunderagivensetof
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 生化 英文 习题