Chapter5 Nucleotides.ppt

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1、Chapter5Nucleotides,Outline,NitrogenousBasesNucleosidesNucleotides,KnowthebasicstructuresPyrimidinesCytosine(DNA,RNA)Uracil(RNA)Thymine(DNA)PurinesAdenine(DNA,RNA)Guanine(DNA,RNA),NitrogenousBases,PyrimidineandPyrimidinebases,PurineandPurinebases,Severalmodifiedpurinebases,StrongabsorbanceofUVlightT

2、heabsorbancepeakvalueis260nmPoorwater-solubility:thispropertyaffectsthelocationofbasepairsonthedouble-helixKeto-enoltautomerism:thispropertycanchangebase-pairingspecificityonthedouble-helix,PropertiesofPyrimidinesandPurines,Keto-enoltautomerism,KnowthesestructurestooD-ribose(inRNA)2-deoxy-D-ribose(i

3、nDNA)Thedifference-2-OHvs2-HThisdifferenceaffectssecondarystructureandstability,PentosesofNucleotides,D-riboseandD-deoxyribose,LinkageofabasetoasugarBaseislinkedviaaglycosidicbondThecarbonoftheglycosidicbondisanomericNamedbyadding-idinetotherootnameofapyrimidineor-osinetotherootnameofapurineConforma

4、tioncanbesynoranti,butonlyantiforpyrimidinenucleotidesSugarsmakenucleosidesmorewater-solublethanfreebases,Nucleosides,Thestructureofnucleosides,Conformationofnucleosidescanbesynoranti,NucleosidephosphatesKnowthenomenclatureMostnucleotidesareribonucleotidesNucleotidesarepolyproticacids,Nucleotides,Ri

5、bonucleotides,ConversionofAMPintoADPandADPintoATP,Deoxyribonucleotides,Cyclicnucleotides,BuildingblocksofDNAandRNANucleoside5-triphosphatesarecarriersofenergy-ATPiscentraltoenergymetabolism-GTPdrivesproteinsynthesis-CTPdrivesphospholipidsynthesis-UTPdrivesglycogensynthesisComponentsofsomecoenzymes:coenzymeIandISignaltransduction:CyclicnucleotidesaresignalmoleculesandregulatorsofcellularmetabolismandreproductionControlofmetabolism:Allostericeffector,FunctionsofNucleotides,