Nucleotides and Nucleic Acids Structures of the four ribonucleotides NH2 G FOPOCH2 OPOCH2 NH> Adenine Guanine OH OH OH OH Adenosine 5'-phosphate Guanosine 5'-phosphate Ribonucleotides NH> U 0 OPOCH2 Cytosine Uracil OHOH OH OH Cytidine 5'-phosphate Uridine 5'-phosphate Cengage Learing.All Rights Reserve Structures of the four ribonucleotides Nucleotides and Nucleic Acids