考题二.docx

考题二.docx

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考题二

Stemisthebase-pairedsegmentofahairpin.

StickyendsarecomplementarysinglestrandsofDNAthatprotrudefromoppositeendsofaduplexorfromendsofdifferentduplexmolecules;canbegeneratedbystaggeredcutsinduplexDNA.

Stopcodonsarethethreetriplets（UAA,UAG,UGA）whichterminateproteinsynthesis.

StranddisplacementisamodeofreplicationofsomevirusesinwhichanewDNAstrandgrowsbydisplacingtheprevious（homologous）strandoftheduplex.

StreptolydiginsinhibittheelongationoftranscriptionbybacterialRNApolymerase.

Stingentreplicationdescribesthelimitationofsingle-copyplasmidstoreplicationparipassuwiththebacterialchromosome.

StringentresponsereferstotheabilityofabacteriumtoshutdownsynthesisoftRNAandrigosomesinapoor-growthmedium.

StructuralgenecodesforanyRNAorproteinproductotherthanaregulator.

SupercoilingdexcribesthecoilingofaclosedduplexDNAinspacesothatitcrossesoveritsownaxis.

Superrepressedmeansthesameasuninducible.

SuppressiondescribestheoccurrenceofchangesthateliminatetheeffectsofamutationwithoutreversingtheoriginalchangeinDNA.

Suppressor（extragenic）isusuallyagenecodingamutanttRNAthatreadsthemutatedcodoneigherinthesenseoftheoriginalcondonortogiveanacceptablesubstitutefortheoriginalmeaning.

Suppressor（intragenic）isacompensatingmutationthatrestorestheoriginalreadingframeafteraframeshift.

Synapsisdescribestheassociationofthetwopairsofsisterchromatidsrepresentinghomologouschromosomesthatoccursatthestartofmeiosis;resultingstructureiscalledabivalent.

Synaptonemalcomplexdescribesthemorphologicalstructureofsynapsedchromosomes.

Syntenicgeneticlocilieonthesamechromosome.

TCellsarelymphocytesoftheT（thymic）lineage;maybesubdivivedintoseveralfunctionaltypes.TheycarryTcR（Tcellreceptor）andareinvolvedinthecell-mediatedimmuneresponse.

Tmistheabbreviationformeltingtemperature.

Tandemrepeatsaremultiplecopiesofthesamesequencelyinginseries.

TATAboxisaconservedA•T-richseptamerfoundabout25bpbdforethestartpointofeacheukaryoticRNApolymeraseIItranscriptionunit;maybeinvolvedinpositioningtheenzymeforcorrectintitiation.

Telomeraseistheribonucleoproteinenzymethatcreatesrepeatingunitsofonestrandatthetelomere,byaddingindividualbases.

Telomereisthenaturalendofachromosome;theDNAsequenceconsistsofasimplerepeatingunitwithaprotrudingsingle-strandedendthatmayfoldintoahairpin.

Temperature-sensitivemutationcreatesageneproductthatisfunctionalatlowtemperaturebutinactiveathighertemperature（thereverserelationshipisusuallycalledcold-sensitive）.

Termainalredundancydescribestherepetitionofthesamesequenceatbothendsof（forexample）aphagegenome.

Terminationcondonisoneofthreetripletsequences,UAG（amber）,UAA（ochre）,orUGAthatcauseterminationofproteinsynthesis;theyarealsocalled‘nonsense’codons.

terminatorisasequenceofDNA.representedattheendofthetranscript,thatcausesRNApolymerasetoterminatetranscription.

Tertiarystructureofaproteindescribestheorganizationinspaceofitspolypeptidechain.

Testcrossinvolvescrossinganunknowngenotypetoarecessivehomozygotesothatthephenotypesoftheprogenycorresponddirectlytothechromosomescarriedbytheparentofunknowngenotype.

Thalassemiaisdieaseofredbloodcellsresultingfromlackofeitherαorβglogin.

ThyminedimmercomprisesachemicallycrosslinkedpairofadjacentthymineresiduesinDNA,aresultofdamageinducedbyultravioletirradiation.

TopoisomeraseisanenzymethatcanchangethelikningnumberofDNA（instepsof1bytypeI;instepsof2bytypeII）.

TopologicalisomersaremoleculesofDNAthatareidenticalexceptforadifferenceinlinkingnumber.

Tracerisaradioactivelylabelednucleicacidcomponentincludedinareassociationreactioninamountstoosmalltoinfluencetheprogressofreaction.

Trailerisanontranslatedsequenceatthe3’endofanmRNAfollowingtheterminationcondon.

TransconfigurationoftwositesreferstotheirpresenceontwodifferentmoleculesofDNA（chromosomes）.

TranscribedspaceristhepartofanrRNAtranscriptionunitthatistranscribedbutdiscardedduringmaturation;thatis,itdoesnotgiverisetopartofrRNA.

TranscriptionissynthesisofRNAonaDNAtemplate.

TranscriptionunitisthedistancebetweensitesofinitiationandterminationbyRNApolymerase;mayincludemorethanonegene.

Transductionreferstothetransferofabacterialgenefromonebacteriumtoanotherbyaphage;aphagecarryinghostaswellasitsowngenesisstationandtransferofeukaryoticcellularsequencesbyretroviruses.

TransfectionofeukaryoticcellsistheacquistionofnewgeneticmarkersbyincorporationofaddedDNA.

TransformationofbacteriadescribestheqcquisitionofnewgeneticmarkersbyincorporationofaddedDNA.

Transformationofeukaryoticcellsreferstotheirconversiontoastateofunrestrainedgrowthinculture,resemblingoridenticalwiththetumorigeniccondition.

TransgenicanimalsarecreatedbyintroducingnewDNAsequencesintothegermlineviaadditiontotheegg.

Transitpeptideistheshortleadersequencecleavedfromproteinsthatareimportedintocellularorganellesbypost-translationalpassageofthemembrane.

Transitionisamutationinwhichonepyrimidineissubstitutedbytheotherorinwhichonepurineissubstitutedfortheother.

TranslationissynthesisofproteinonthemRNAtemplate.

Translocationofachromosomedescribesarearrangementinwhichpartofchromosomeisdetachedbybreakageandthenbecomesattachedtosomeotherchromosome.

Translocaationofagenereferstotheappearanceofanewcopyatlocationinthegenomeelsewherefromtheoriginalcopy.

Translocationofaproteinreferstoitsmovementacrossamembrane.

TranslocationoftherigbosomeisitsmovementonecodonalongmRNAaftertheadditionofeachaminoacidtothepolypeptidechain.

Transmembraneproteinisacomponentofamembrance;ahydrophobicregionofregionsoftheproteinresidesinthemembrane,andhydrophilicregionsareexposedononeorbothsidesofthemembrane.

Transplantationantigenisproteincodedbyamajorhistocompatibilitylocus,presuentonallmammaliancells,involvedininteractionsbetweenlymphocytes.

Transposaesistheenzymeactivityinvolvedininsertionoftransposonatanewsite.

TranspostionimmunityreferstotheabilityofcertaintransposonstopreventothersofthesametypefromtransposingtothesameDNAmolecule.

TransposonisaDNAsequenceabletoinsertitselfatanewlocationinthegenome（withoutanysequencerelationshipwiththetargetlocus）.

Transpostionreferstothemovementofatransposontoanewsiteinthegenome.Seealsononreplicativetransposition,replicativetransposition,andconservativetransposition.

Transvectiondescribestheabilityofalocustoinfluenceactiveityofanalleleontheotherhomoloueonlywhentwochromosomesaresynapsed.

Transversionisamutationinwhichapurineisreplacedbyapyrimidineorviceversa.

True-breedingorganismsarehomozygousforthetraitunderconsideration.

TwistingnumberofaDNAisthenumberofbasepairsdividedbythenumberofbasepairsperturnofthedoublehelix.

UnderwindingofDNAisproducedbynegativesupercoiling（becausethedoublehelixisitselfcoiledintheoppositesensefromtheintertwiningofthestrands）.

Unequalcrossing-overdescribesarecombinationeventinwhichthetworecombiningsiteslieatnonidenticallocationsinthetwoparentalDNAmolecules.

Unidirectionalreplicationreferstothemovementofasinglereplicationforkfromagivenorigin.

Uninduciblemutantscannotbeinduced.

UnscheduledDNAsynthesisisanyDNAsynthesisoccurringoutsidetheSphaseoftheeuikaryoticcell.

Uppromotermutationsincreasethefrequencyofinitiationoftranscription.

Upstreamidentifiessequencesproceedingintheoppositedirectionfromexpression;forexample,thebacterialpromoterisupstreamfromthetranscriptionunit,theinitiationcodonisupstreamofthecodingregion.

URFisanopen（unidentified）readingframe,presumedtocodeforprotein,butforwhichnoproducthasbeenfound.

Vgeneissequencecodingforthemajorpartofthevariable（N-termainal）regionofanimmunoglobulinchain.

VariableregionofanimmunoglobulinchainiscondedbytheVgeneandvariesextensivelywhendifferentchainsarecompared,astheresultofmultiple（different）genomiccopiesandchangesintroducedduringconstructionofanactiveimmunoglobulin.

Variegationofphenotypeisproducedbyachangeingenotypeduringsomaticdevelopment.

Vector—seecloningvector.

Vesiclesaresmallbodiesboundedbymembrane,derivedbybuddingfromonemembrane,oftenabletofusewithanothermembrane.

Virionisthephysicalvirusparticle（irrespectiveofitsabilitytoinfectcellsandreproduce）.

Virulentphagemutantsareunabletoestablishlysogeny.

WobblehypotheisaccountsfortheabilityofatRNAtorecognizemorethanonecondonbyunusual（non-G·C,A·T）pairingwiththethirdbaseofacodon.

Writhingnumberisthenumberoftimesaduplxaxiscrossesoveritselfinspace.

Zerotime-bindingDNAenterstheduplexformatthestartofareassociationreaction;resultsfromintramolecularreassociationofinvertedrepeats.

Zincfingerproteinhasarepeatedmotifofaminoacidswithcharacteristicspacingofcysteinesthatmaybeinvovedinbindingainc;ischaracteristicofsomeproteinsthatbindDNAand/orRNA.

ZooblotdescribestheuseofSouthernblottingtotestthe