Life their DNA inside the cell nucleus and some of their DNA in organelles, such as mitochondria or chloroplasts. In contrast, prokaryotes (bacteria and archaea) store their DNA only in the cytoplasm. Within the chromosomes, chromatin proteins such as histones compact and organize DNA. These compact structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed. DNA was first isolated by Friedrich Miescher in 1869. Its molecular structure was identified by James Watson and Francis Crick in 1953, whose model-building efforts were guided by X-ray diffraction data acquired by Rosalind Franklin. Life is
Francis Crick some of which were performed by Crick. The details of the code came mostly from work by Marshall Nirenberg and others who synthesized synthetic RNA molecules and used them as templates for "in vitro" protein synthesis. Nirenberg first announced his results to a small audience in Moscow at a 1961 conference. Crick's reaction was to invite Nirenberg to deliver his talk to a larger audience. An enduring controversy has been generated by Watson and Crick's use of DNA X-ray diffraction data collected by Franklin and Wilkins. The controversy arose from the fact that some of Franklin's unpublished data were used