Nucleosides NH OH NH2 oH N HON N HO N HO N HOCH2 O HOCH HOQ2 O HOCHO O HH HH H H H H H OH OH OHOH OHOH OHOH 腺嘌呤核苷鸟嘌呤核苷 胞嘧啶核苷 尿嘧啶核苷 Adenosine Guanosine Cytidine UridineAdenosine Guanosine Cytidine Uridine Nucleosides 腺嘌呤核苷 鸟嘌呤核苷 胞嘧啶核苷 尿嘧啶核苷 N N OH HO N N NH2 HO N N OH H2N N N N N N N NH2 O H H OH H OH H HOCH2 HOCH2 O H H OH H OH H O H H OH H OH H HOCH2 O H H OH H OH H HOCH2