Rosalind Franklin (1920-1958) was a chemist and crystallographer who was instrumental in the discovery of the structure of DNA. Franklin set up an X-ray diffraction lab and photographed DNA. Unbeknownst to her, one of her photographs was seen by Watson and Crick, who used it (along with her data) to propose the double helix structure of DNA. She also did important work on viruses before her untimely death.
photo by Jewish Chronicle Archive/Heritage