The core principle of cellular biology governing genetic replication is the mechanism of complementary base pairing within the DNA double helix structure. This theory dictates that nitrogenous bases form specific pairs based on geometric compatibility and hydrogen bond count: purines (adenine, guanine) pair exclusively with pyrimidines (thymine, cytosine) via two or three hydrogen bonds, respectively, ensuring structural uniformity and high-fidelity information transfer. As a foundational concept in molecular genetics, this rule explains the fidelity of DNA replication and serves as the mechanistic basis for downstream biological processes including transcription, polymerase chain reaction (PCR), and genetic editing.
Prerequisite chain context: requires DNA Structure and Heredity.