Deoxyribonucleic acid or D.N.A. is a molecule that is a double helix composed of subunits known as nucleotides. A nucleotide consists of a phosphate group, a sugar called deoxyribose and one of four nitrogenous bases. A nucleotide is joined to another nucleotide at the nitrogenous base end of the molecule with weak hydrogen bonds holding the complementary bases together. What your example above has are correct bases paired together. In D.N.A., adenine or A bonds to thymine or T, cytosine C bonds to guanine or G.