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,
Rosalind Franklin and DNA was a general consensus at the time that they were at the inside); and the other is that DNA exists in two forms, a crystalline (dry form) A-DNA and a hydrated (wet form) B-DNA. With her PhD student Raymond Gosling, she produced a series of X-ray images of DNA. The photograph (number 51, hence, popularised as Photo 51) of B-DNA taken in May 1952 was especially crucial. X-ray crystallography did not immediately show the precise helical structure. Franklin chose to work on A-DNA, while B-DNA was given to Maurice Wilkins. By the early 1953, Franklin was aware that both A