Question

Describe three features of the structure of DNA that X-ray crystallography helped Rosalind Franklin identify. a) Helical structure, base pairing, and sugar-phosphate backbone

b) Double-stranded nature, hydrogen bonding, and alpha-helix formation
c) Triple helix structure, peptide bonds, and minor grooves
d) Single-stranded nature, disulfide linkages, and beta-sheet formation

Answer 1

X-ray crystallography helped Rosalind Franklin identify the helical structure, base pairing, and sugar-phosphate backbone of DNA.

Step-by-step explanation:

Rosalind Franklin used X-ray crystallography to identify three features of the structure of DNA:

1. Helical structure: X-ray crystallography helped in determining that DNA has a double helix shape, with two strands of nucleotides coiling around each other.
2. Base pairing: The X-ray diffraction pattern provided by Franklin revealed that the two strands of DNA are held together by complementary base pairing. Adenine (A) always pairs with thymine (T), and guanine (G) always pairs with cytosine (C).
3. Sugar-phosphate backbone: X-ray crystallography revealed that the two strands of DNA are connected by a sugar-phosphate backbone, alternating between deoxyribose sugar and phosphate groups.