[Campbell Biology P.367] Rosalind Franklin's X-ray diffraction images were crucial to unders... | Practice Question

Rosalind Franklin's X-ray diffraction images were crucial to understanding DNA structure. Which of the following was NOT a key insight derived from her work that contributed to the development of the double helix model?

  • A: Confirmation that DNA has a helical shape.
  • B: Evidence that the DNA helix is made up of two strands, not three.
  • C: Determination of the exact sequence of nitrogenous bases along a DNA strand.
  • D: Information about the width of the helix and the spacing of the nitrogenous bases along it.

Explanation

Rosalind Franklin's X-ray diffraction images revealed the helical shape of DNA, implied its two-stranded nature, and provided critical measurements for the helix's width and the spacing of its bases. However, X-ray diffraction cannot determine the specific sequence of nitrogenous bases; that requires other methods like sequencing.