Adenine molecule and phosphate group. Molecular model of adenine (right),one of four nucleotide bases found in DNA (deoxyribonucleic acid),and a phosphate group (left). Atoms (spheres) are colour-coded: carbon (yellow),nitrogen (green),hydrogen (white),oxygen (pink,small) and phosphorus (red,large). In the DNA molecule,adenine bonds with thymine,holding the double helix together. Phosphate-sugar groups form the backbone of the helical strands. It is the sequence of the bases along a DNA strand that encodes the genetic information that is the basis of all life on Earth |