20th century in science biologically relevant molecules, they were, till the end of the 20th century, more a collection of rules, observations, and recipes than rigorous ab initio quantitative methods. This heuristic approach triumphed in 1953 when James Watson and Francis Crick deduced the double helical structure of DNA by constructing models constrained by and informed by the knowledge of the chemistry of the constituent parts and the X-ray diffraction patterns obtained by Rosalind Franklin. This discovery lead to an explosion of research into the biochemistry of life. In the same year, the Miller–Urey experiment demonstrated that basic constituents of protein, simple amino acids,
Timeline of United States discoveries chloride 1936 Elliptical galaxies 1936 Muons 1936 Vitamin E 1936 Sodium thiopental 1937 Niacin 1937 Electron capture 1938 Fluropolymers 1938 Animal echolocation 1938 Carme 1938 Lysithea 1940 Plutonium 1942 Cyanoacrylate 1943 Streptomycin 1944 Americium 1944 Curium 1946 Cloud seeding 1948 Warfarin 1948 Miranda 1948 Serotonin 1948 Tetracycline 1949 Nereid 1949 Berkelium 1950 Californium 1951 Barium stars 1951 Ananke 1952 Polio vaccine 1952 Einsteinium 1952 Rapid eye movement 1953 DNA structure In 1953, based on X-ray diffraction images and the information that the bases were paired, James D. Watson along with Francis Crick co-discovered what is now widely accepted as the