分子生物学名词解释-英文

11.DNADenaturation(变性)WhenduplexDNAmoleculesaresubjectedtoconditionsofpH,temperature,orionicstrengththatdisruptbase-paringinteractions,theDNAmoleculehaslostits’nativeconformation,anddoublehelixDNAisseparatedtosinglestrandDNAasindividualrandomecoils.Thatis,theDNAisdenatured.2.Renaturation（复性）Removingthedenaturationfactorsslowlyorinproperconditions,thedenaturedDNA(ssDNA)restorenativestructure(dsDNA)andfunctions.ThisprocessisdependentonbothDNAconcentrationandtime.3.Hybridization（核酸分子杂交）whenheterogeneousDNAorRNAareputtogether,theywillbecometoheteroduplexviathebase-pairingrulesduringrenaturationiftheyarecomplementaryinparts(notcompletely).Thisiscalledmolecularhybridization.4.Hyperchromiceffect（增色效应）Theabsorbanceat260nmofaDNAsolutionincreaseswhenthedoublehelixisseparatedintosinglestrandsbecauseofthebasesunstack.5.Ribozyme（核酶）aretheRNAmoleculeswithcatalyticactivity.Theactivityoftheseribozymesofteninvolvesthecleavageofanucleicacid.6.Denovosynthesis(从头合成)Denovosynthesisofnucleotidesbeginswiththeirmetabolicprecursors:aminoacids,ribose-5-phosphate,onecarbonunits,CO2.mostlyinliver.7.Salvagepathways（补救合成）Salvagepathwaysrecyclethefreebasesandnucleosidesreleasedfromnucleicacidbreakdown.Mostlyinbrainandmarrow.8.Semi-conservativereplication(半保留复制）DNAissynthesizedbyseparationofthestrandsofaparentalduplex,eachthenactingasatemplateforsynthesisofacomplementarystrandbasedonthebase-paringrule.Eachdaughtermoleculehasoneparentalstrandandonenewlysynthesizedstrand.9.Telomere（端粒）：Specializedstructureattheendofalineareukaryoticchromosome,whichconsistsofproteinsandDNA,tandemrepeatsofashortG-richsequenceonthe3'endingstrandanditscomplementarysequenceonthe5'endingstrand,allowsreplicationoftheextreme5'endsoftheDNA2withoutlossofgeneticinformationandmaintainsthestabilityofeukaryotechromosome.10.Telomerase（端粒酶）AnRNA-containingreversetranscriptasethatusingtheRNAasatemplate,addsnucleotidestothe3'endingstrandandthuspreventsprogressiveshorteningofeukaryoticlinearDNAmoleculesduringreplication.11.Reversetranscription(逆转录）Synthesisofadouble-strandDNAfromanRNAtemplate.12.Reversetranscriptase(逆转录酶）ADNApolymerasethatusesRNAasitstemplate.activity:RNA-dependentDNApolymerase;RNAseH;DNA-dependentDNApolymerase13.Thecentraldogma(中心法则）ItdescribedthattheflowofgeneticinformationisfromDNAtoRNAandthentoprotein.Accordingtothecentraldogma,DNAdirectsthesynthesisofRNA,andRNAthendirectsthesynthesisofproteins.14.asymmetrictranscription（不对称转录）1..TranscriptiongenerallyinvolvesonlyshortsegmentsofaDNAmolecule,andwithinthosesegmentsonlyoneofthetwoDNAstrandsservesasatemplate.2.ThetemplatestrandofdifferentgenesisnotalwaysonthesamestrandofDNA.Thatis,inanychromosome,differentgenesmayusedifferentstrandsastemplate.15.templatestrand（模板链）TheDNAstrandthatservesasatemplatefortranscription.(Therelationshipbetweentemplateandtranscriptisbaseparingandanti-parallel)16.non-templatestrand(orcodingstrand)（编码连）TheDNAstrandthatoppositestothetemplatestrand.(NotethatithasthesamesequenceasthesynthesizedRNA,exceptforthereplacementofUwithT)17.promoteristheDNAsequenceatwhichRNApolymerasebindstoinitiatetranscription.Itisalwayslocatedontheupstreamofagene.18.Splitgenes(断裂基因)SplitgenesarethoseinwhichregionsthatarerepresentedinmaturemRNAsorstructuralRNAs(exons)areseparatedbyregionsthataretranscribedalongwithexonsintheprimaryRNAproductsofgenes,butareremovedfromwithintheprimaryRNAmoleculeduringRNAprocessing3steps(introns).19.Exon(外显子)canbeexpressedinprimarytranscriptandarethesequencesthatarerepresentedinmatureRNAmolecules,itencompassesnotonlyprotein-codinggenesbutalsothegenesforvariousRNA(suchastRNAsorrRNAs)20.Intron（内含子）canbeexpressedandbetheinterveningnucleotidesequencesthatareremovedfromtheprimarytranscriptwhenitisprocessedintoamatureRNA.21.Spliceosome（剪切体）AmulticomponentcomplexcontainsproteinsandsnRNAsthatareinvolvedinmRNAsplicing.22.Translation（翻译）TheprocessofproteinsynthesisinwhichthegeneticinformationpresentinanmRNAmolecule(transcribedfromDNA)determinesthesequenceofaminoacidsbythegeneticcodons.Translationoccursonribosomes.23.geneticcodon（密码子）ThegeneticcodeisatripletcodereadcontinuouslyfromafixedstartingpointineachmRNA,alsocalledtriplet.GeneticcodedefinestherelationshipbetweenthebasesequenceofmRNAandtheaminoacidsequenceofpolypeptide.24.Degeneracyofcode（密码子简并性）Onecodonencodesonlyoneaminoacid;Morethan2codonscanencodethesameaminoacid;Mostcodonsthatencodethesameaminoacidhavethedifferenceinthethirdbaseofthecodon.25.ORF（开放阅读框架）ThenucleotideacidssequencesinmRNAmoleculefrom5’AUGto3’stopcodon(UAAUAGUGA).Itconsistsofagroupofcontiguousnonoverlappinggeneticcodonsencodingawholeprotein.Usually,itincludesmorethan500geneticcodons.26.Shine-Dalgarnosequence（SD）isasequenceupstreamthestartcodoninprokaryoticmRNAthatcanbasepairstoa•UCCU•sequenceatorverynearthe3'endof16SrRNA,therebybindingthemRNAandsmallribosomalsubunitbyeachother.27.Polyribosome（多聚核糖体）Ribosomes(10~100)aretandemlyarrangedononemRNAandmoveinthe4directionof5’to3’.SuchacomplexofonemRNAandanumberofribosomesiscalledpolyribosome.28.signalpeptide（信号肽）Itisashortcons