noun 下载 🔗分享 嘧啶 A diazine in which the two nitrogen atoms are in the meta- positions; it is the basis of three of the bases found in DNA and RNA: thymine, uracil and cytosine Examples : "The science lesson explained that pyrimidines, like thymine and cytosine, are essential building blocks of DNA's genetic code. " 科学课上解释说,嘧啶,比如胸腺嘧啶和胞嘧啶,是DNA遗传密码的重要组成部分。 chemistry biochemistry biology compound 与AI对话词汇游戏阅读练习