[SCI] Molecular Biology & Biochemistry

Molecular Biology is the study of biological processes at the molecular level — DNA, RNA, proteins, and the mechanisms of gene expression — founded in the 1940s–1950s at the intersection of physics, chemistry, and biology.

Overview

Schrödinger's What is Life? (1944) proposed that genes must be aperiodic crystals storing information, inspiring physicists (Crick, Wilkins) to enter biology. Chargaff's rules (1950) showed base pairing in DNA. Franklin's X-ray diffraction (1952) revealed the helical structure. Watson and Crick's double helix model (1953) showed how genetic information is stored and copied. Crick's Central Dogma (1958) described the information flow: DNA → RNA → Protein. The genetic code was cracked (1961–1965). PCR (Mullis 1983) allowed amplification of specific DNA sequences, democratising molecular biology.

Biochemistry — the chemistry of living systems — developed in parallel, elucidating metabolic pathways (Krebs cycle 1937, ATP synthesis), enzyme kinetics, and membrane transport.

Key Figures & Recognition

• James Watson (1928–) & Francis Crick (1916–2004): DNA double helix. Nobel Prize 1962 (shared with Wilkins; Franklin died 1958).
• Rosalind Franklin (1920–1958): X-ray diffraction of DNA. No Nobel (died before award; widely considered an injustice).
• Frederick Sanger (1918–2013): Protein sequencing (Nobel 1958) and DNA sequencing (Nobel 1980) — two separate prizes.
• Kary Mullis (1944–2019): PCR. Nobel Prize 1993.

Seminal Papers

• Watson, J. & Crick, F. "A Structure for Deoxyribose Nucleic Acid." Nature 171 (1953).
• Crick, F. "On Protein Synthesis." Symp. Soc. Exp. Biol. 12 (1958) — Central Dogma.
• Sanger, F. et al. "DNA sequencing with chain-terminating inhibitors." PNAS 74 (1977)

What This Enables

• [SCI] Genomics & Computational Biology — Genomics is molecular biology applied at genome scale: sequencing, assembly, and annotation extend molecular biology methods.

Discovery Character

Surprise level: High — The discovery that the biological blueprint is a digital code stored in a linear sequence of four bases — and that it operates via a simple copying mechanism — was surprising in its elegance and simplicity. That physics and chemistry could fully explain the basis of life and heredity was not accepted until the 1950s.

Mode: Systematic with competitive pressure and ethical shadow. Watson and Crick used model-building, Chargaff's base-pairing rules, and Franklin's X-ray data in a systematic race against Pauling. Franklin's Photo 51 was shown to Watson by Wilkins without her knowledge — the ethical complexity surrounds what was scientifically systematic. Crick and Watson's key insight (antiparallel strands, base-pairing) was a creative leap that clicked into place when they saw the right model.