Molecular design. Computer artwork of plans for a molecular model of the nucleotide adenine with the finished model. The atoms are shown as spheres and are colour coded: carbon (yellow), nitrogen (blue) and hydrogen (white). Adenine is a nucleotide. It is one of the four nucleotide bases that are found in deoxyribonucleic acid (DNA). DNA is split into sections called genes. The sequence of nucleotides within a gene determine its protein product.