In part 1 of this two-part episode, I discuss the double helix shape of DNA, the structure of nucleotides, base-paring between nitrogenous bases, the genetic code, codons, DNA reading frames, the one-gene one-polypeptide hypothesis, and the Central Dogma of Molecular Biology. This basic structural knowledge will provide the basis for a more detailed discussion of the processes of DNA replication, transcription and translation in part 2 of this topic. Recommended background knowledge of episodes 10 (The Cell) and 18 (Biochemistry Basics).