Question

Rosalind Franklin’s photographs of the X-ray diffraction pattern of DNA provided important clues about the structure of the DNA molecule. What was revealed by the photograph that enabled Watson and Crick to build their model of the DNA molecule? Select all that apply. A. The nitrogenous bases form the backbone on the outside of each DNA strand. B. The DNA strands are twisted around each other. C. There are two strands in the DNA molecule. D. The nitrogenous bases are near the center of the DNA molecule.

Answer 1

Answer:

The correct answers: B, C and D.

Explanation:

• X-ray diffraction studies of the DNA reveal the following:

1. The DNA is comprised of two strands which are coiled around each other in the shape of a helix.
2. The backbone of the DNA is made up of phosphate and deoxyribose groups, alternately, which are exposed towards the outside of the helix.
3. The nitrogenous bases which form the hydrogen bonds that link the two helices are directed towards the centre of the helix.