Nucleotide is a compound consisting of a nucleoside linked to a phosphate group. Nucleotides is the molecular building blocks of nucleic acids, RNA and DNA, both of which are essential biomolecules within all life-forms on Earth. The four bases used in DNA are adenine (A), cytosine (C), guanine (G) and thymine (T). In RNA, the base uracil (U) takes the place of thymine