Question

What did this X-ray crystallography indicate about DNA?

a. The ratios of the base pairs were always one to one
b. The structure of DNA was helical
c. DNA contained hydrogen bonds
d. The building blocks of DNA were called nucleotides.

Answer 1

The correct answer is: b. The structure of DNA was helical

This photo known as Photo 51 is an X-ray diffraction image of crystallized DNA made by Rosalind Franklin. This photo helped Watson and Crick to define the final structure of DNA molecule. This diffraction pattern was essential for the construction of DNA model and it determined the helical nature of the double antiparallel helix strands.