In 1952, Rosalind Franklin produced an image of DNA that suggested it contained two strands twisted in a double helix with a phosphate backbone and bases inside.
Franklin calculated the diameter of DNA, the distance between strands and bases, the angle of the helix, and the number of bases per coil.
Watson and Crick used this information to build and accurate model of DNA.
Explanation:
after the question it asks what did you add & these are pretty much the answer
Discovery of structure of DNA by Franklin and Watson and Crick.
Explanation:
Rosalind Franklin was researching about DNA structure at the King’s College at London based on x-ray diffraction studies; while, Crick and Watson were researching on the same at the Cambridge University based on Linus Pauling discovery of proteins.
Once when Watson happen to listen to Franklin’s lecture upon DNA structure and how it depends on relative humidity of the air and other facts relating to DNA; he along with Crick made physical DNA models which became a big failure.
Later, Franklin found that a wet form of DNA with high humidity had a helix like structure. This point became the base of later discovery of Watson and Crick’s double helix model of DNA along with the discovery of DNA molecules being made up of double chain of nucleotides.
