DNA: THE MOLECULE OF HEREDITY. CHAPTER 9. Big Idea. The Big Idea! The structure of DNA, the molecule of heredity, enables the molecule to copy itself. Enduring Understanding. Students will understand that:
Purines and Pyramidines
1. Enzymes called DNA helicases begin to unzip the double helix at numerous places along the chromosomes called origins of replication. That is, the hydrogen bonds connecting base pairs are broken, the original molecules separates, and the bases on each strand are exposed.