1·Adenine and guanine are purines and cytosine and thymine are pyrimidines.
腺嘌呤和鸟嘌呤是嘌呤和胞嘧啶和胸腺嘧啶是嘧啶。
2·The most abundant bases are cytosine, thiamine , and uracil ( pyrimidines ) and adenine and guanine ( purines ) .
最丰富的碱基是胞嘧啶， 胸腺嘧啶， 尿嘧啶，腺嘌呤和鸟嘌呤。
3·The CDR makes cells put their ordinary activities on hold and instead switch on their defence systems, in reaction to high levels in the bloodstream of chemicals called purines.
即cdr系统会让细胞暂时停止它们的日常活动，反而让其打开了它们的防御系统，以应对血液中高浓度的，一种称为嘌呤的化学物质。
4·It is important in the growth and reproduction of cells, participating in the synthesis of purines and thymine.
在细胞生长和再生中也很重要，参与了嘌呤和嘧啶的合成。
5·The most abundant bases are cytosine, thiamine, and uracil (pyrimidines) and adenine and guanine (purines).
最丰富的碱基是胞嘧啶，胸腺嘧啶，尿嘧啶，腺嘌呤和鸟嘌呤。