Final answer:
Rosalind Franklin captured critical X-ray diffraction images of DNA, contributing to the understanding of its double helix structure. Erwin Chargaff formulated rules about DNA base pairing critical for understanding DNA's structure. James Watson and Francis Crick used Franklin's data to construct the first accurate model of DNA's structure, which earned them a Nobel Prize.
Step-by-step explanation:
The discovery of the structure of DNA was a pivotal moment in the history of science, with key contributions from several scientists:
Rosalind Franklin was a British chemist whose expertise in X-ray crystallography enabled her to capture X-ray diffraction images of DNA. These images provided critical information about DNA's structure, revealing it to be a double helix and helping to determine its size. Franklin's research also uncovered that DNA can exist in two forms – the 'A' form, which is short and wide, and the 'B' form, which is long and thin.
Erwin Chargaff contributed to our understanding of DNA through Chargaff's rules, which state that DNA from any cell of any organism should have a 1:1 ratio of pyrimidine and purine bases and, more specifically, that the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine. This finding was crucial for elucidating DNA's base-pairing mechanism.
James Watson and Francis Crick are widely credited with the first accurate model of DNA's structure. Using the data from Franklin's X-ray diffraction images, they proposed the double helix model of DNA and deduced the pairing method of the nucleotide bases. Their work earned them, along with Maurice Wilkins, the 1962 Nobel Prize in Physiology or Medicine.