Which scientist contributed the X-ray diffraction image that helped Watson and Crick develop the DNA double helix model?

Which scientist contributed the X-ray diffraction image that helped Watson and Crick develop the DNA double helix model?

• A. Francis Crick
• B. James Watson
• C. Linus Pauling
• D. Rosalind Franklin

Answer: (D)

Rosalind Franklin provided crucial X-ray diffraction data that revealed DNA’s helical shape. Her high-quality X-ray images, including the famous Photo 51, showed patterns consistent with a regular helix and gave key measurements—the molecule’s width and the spacing between base pairs. This information helped Watson and Crick infer a double-helix structure with about 10 base pairs per turn and a consistent diameter, bringing the model in line with experimental evidence. The other names contributed in different ways—one helped build the model, and another proposed an alternative (incorrect) structure—but Franklin’s diffraction image supplied the decisive structural clue that pointed toward the double helix.

Rosalind Franklin provided crucial X-ray diffraction data that revealed DNA’s helical shape. Her high-quality X-ray images, including the famous Photo 51, showed patterns consistent with a regular helix and gave key measurements—the molecule’s width and the spacing between base pairs. This information helped Watson and Crick infer a double-helix structure with about 10 base pairs per turn and a consistent diameter, bringing the model in line with experimental evidence. The other names contributed in different ways—one helped build the model, and another proposed an alternative (incorrect) structure—but Franklin’s diffraction image supplied the decisive structural clue that pointed toward the double helix.