The Central Dogma of Molecular Biology: Proposed by Francis Crick (1958), genetic information flows strictly from $\text{DNA} \xrightarrow{\text{Transcription}} \text{mRNA} \xrightarrow{\text{Translation}} \text{Protein}$.
Complementary Base Pairing: Chargaff's rules dictate Watson-Crick double hydrogen bonds between Adenine-Thymine ($A=T$, in RNA $A=U$) and triple bonds between Cytosine-Guanine ($C \equiv G$).
Genetic Code Degeneracy: 64 triplet codons code for 20 amino acids and 3 termination signals (UAA, UAG, UGA). Translation always initiates at the start codon $\text{AUG}$ (Methionine).
Mutational Dynamics: Point substitutions can cause silent (synonymous), missense (amino acid substitution), or nonsense (premature stop) mutations. Indel insertions/deletions alter reading frames (frameshift).