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1、第十章 遗传的分子基础,Proof of DNA as Genetic Material,Transformation转化 in Bacteria,( Frederick Griffith . 1928 ),Characteristics of S.pneumoniae肺炎(链)双球菌 Strains When Grown on Blood Agar Medium,Colony Morphology菌落形态 Type Appearance Size Capsule荚膜 Virulence毒性 II R Rough Small Absent Avirulent II S Smooth Large
2、 Present Virulent,Colony Morphology Type Appearance Size Capsule Virulence IIIR Rough Small Absent Avirulent IIIS Smooth Large Present Virulent,Reaction with Antiserum Prepared Against Type Type II S Type III S II R None None II S Agglutination凝集 None,Reaction with Antiserum Prepared Against Type Ty
3、pe II S Type III S III R None None III S None Agglutination,DNA : the Transformation Material,( Oswald Avery and his colleagues 1944),The analytical tools Avery etc. used were the following: 1.Ultra- centrifugation超速离心 2. Electrophoresis电泳 3.Ultraviolet Absorption紫外吸收 4. Elementary Chemical Analysis
4、化学元素分析,The Hershey-Chase Experiment,Proof of RNA as Genetic Material,A variety of strains of tobacco mosaic virus tobacco mosaic virus (TMV) exist. Many strains cause distinctive symptoms on indicator plants,TMV particles can be dissociated into解离 RNA and protein components. The separated RNA and pr
5、otein can be mixed together to reform infectious viral particles.,第二节 核酸的化学组成及结构分析,Nucleic Acid Chemistry,Johann Misecher ( 1844 1895 ) “ nuclein ”.,Ribonucleic acids ( RNA ),Deoxyribonucleic acids ( DNA ),核 糖 核 苷 酸,1,2,3,4,5,脱 氧 核 糖 核 苷 酸,核糖,2-脱氧核糖,嘧啶环,嘌呤环,胞嘧啶,尿嘧啶,胸腺嘧啶,鸟嘌呤,腺嘌呤,尿苷,脱氧腺苷酸,蛋白质生物合成,脂质代谢
6、,能量代谢,3-5磷酸二酯键,DNA Structure,Erwin Chargaff and Chargaff rules A+G = T+C,The Double Helix,Watson and Crick ( 1953 ),X-ray diffraction photograph of the B form of purified DNA fibers.,The Nobel Prize in Physiology or Medicine 1962,DNA双链构象改变因素: 1、核苷酸顺序 2、碱基组成 3、盐的种类 4、相对湿度,Tm ( melting temperature解链温度
7、 ),The temperature at which a population of double-stranded nucleic molecules is half-dissociated into single strands. This is taken to be the melting temperature for that species of nucleic acid.,Denaturation变性 and Renaturation复性,DNA紫外吸收,rRNA ( ribosomal RNA ) mRNA (messenger RNA ) tRNA ( transfer RNA ) snRNA ( small nuclear RNA ) antisense RNA telomerase RNA primer ( in vivo ),DNA的复制,The Meselson-Stahl experiment,Enzymology酶学 of DNA Replication,电镜下显示的DNA的复制图象,环状双链DNA复制方式,滚环复制:噬菌体X174 D环复制:线粒体,质粒 -型复制:大肠杆菌DNA,滚环复制,D环复制,
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