The structure of nucleotide monomers. A nucleotide is made of a nucleobase (also termed a nitrogenous base), a five-carbon sugar (either ribose or 2-deoxyribose) depending on if it is DNA or RNA, and one or, depending on the definition, more than one phosphate groups.his nucleotide contains the five-carbon sugar deoxyribose, a nitrogenous base called adenine, and one phosphate group.