三、基因的化学本质和作用染色体的主要化学组成是 DNA 和组蛋白,染色体上的基因带有遗传信息,从各方面的资料来看,基因的化学成分就是 DNA。(一)DNA 的结构与遗传信息DNA 分子是由两条多核苷酸链所形成的双螺旋结构。每条链都由多个核苷酸相连而成。每个核苷酸由一个脱氧核糖、一个磷酸、一个碱基所构成。构成 DNA 的碱基包括两种嘌呤和两种嘧啶,即腺嘌呤(A)、鸟嘌呤(G)、胞嘧啶(G)和胸腺嘧啶(T)。因此,依所含碱 Third, the chemical nature and role of the gene The main chemical composition of the chromosome is DNA and histone, the gene on the chromosome with genetic information, from all aspects of the data, the chemical composition of the gene is DNA. (A) DNA structure and genetic information DNA molecules are double helix structures formed by two polynucleotide chains. Each chain consists of multiple nucleotides. Each nucleotide consists of one deoxyribose, one phosphate, and one base. The bases that make up the DNA include two purines and two pyrimidines, adenine (A), guanine (G), cytosine (G), and thymine (T). Therefore, according to the alkali