碱基、核苷、核苷酸的概念和关系 Pyrimidines Purihes H.N Cytosine Thymine Uracil Adenine Guanine Nitrogenous base Phosphate Pentose sugar HOCH2 0 OH O HO Ribose (in RNA) Doxyribose(in DNA) ✉碱基、核苷、核苷酸的概念和关系 Nitrogenous base Pentose sugar HOCH2 H OH Doxyribose (in DNA) HOCH2 HO OH Ribose (in RNA) Phosphate Pyrimidines Cytosine Thymine Uracil C T U Purihes Adenine Guanine A G