DNA: The Molecule of Heredity - The Biology Corner Review the structure of DNA and the experiments that lead to the establishment of it as the molecule of heredity. ... Reinforcement: The Molecule of Heredity (DNA) 1. A nucleotide is made of three parts: a _____ group, a five carbon _____, and a nitrogen containing _____ 2.The sides of the DNA ladder consist of alternating _____ and phosphates. ...