碱基配对原则

在DNA分子的双螺旋结构中，位于两条多核苷酸链上的嘌呤碱基和嘧啶碱基可以围绕着螺旋轴通过形成氢键而互相搭配成对，碱基间这种形式的结合，就称为碱基配对.碱基配对的原则是：（1）嘌呤碱基专与嘧啶碱基配对，而且腺嘌呤（A）专与胸腺嘧啶（T）配对（在RNA分子中，腺嘌呤专与尿嘧啶（U）配对）；鸟嘌呤（G）专与胞嘧啶（C）配对.（2）四种可能的碱基对为A—T、T—A、G—C和C—G.A和T间构成两个氢键，G和C间构成三个氢键.四种碱基对的大小几乎相同.（3）配对的两个碱基之间是互补的，这样有利于氢键的形成，对双螺旋结构起稳定作用.碱基配对原则，对DNA的半保留复制，具有特别重要的意义.它对遗传信息的稳定传递提供了分子基础.保证亲代的遗传信息完整地传递给子代，使子代获得亲代的遗传性状.In the doublehelixstructure ofDNAmolecules, located in more than two purine nucleotide chain bases and pyrimidine bases can be around the screwaxisthrough the formation of hydrogenbonds with each other in pairs, this form of integration between bases on the is called base pairing. base pairing principles are: (1) purine and pyrimidine bases specifically base pairing, and adenine (A) specifically with thymine (T) pairs (in the RNA molecules, adenine College and uracil (U) pair); guanine (G) College and cytosine (C) pair. (2) four possible base pairs for the A-T, T-A, G-C and C-G.A , and T form two hydrogen bonds between, G, and C constitute the three hydrogen bonds between. four kinds of base pairs is almost the same size. (3) matching between the two bases are complementary, so that is conducive to hydrogen bond formation of the double helix structure has a stabilizing effect. the principle of base pairing of the semi-conservative DNA replication, has a special significance. It passed the stability of the genetic information provides a molecular basis. to ensure parental generation of the genetic information passed to the son of a complete generation, so that offspring receive parental genetic trait.