Question

question 9 of 10
which best describe the structure of dna?
a. base backbones with sugars on the inside
b. pyrimidine backbones with purines on the inside
c. sugar-phosphate backbones with bases on the inside
d. a backbone of bases with sugars on the outside

Explanation:

DNA has a double - helix structure. The sugar (deoxyribose) and phosphate form the backbone of each strand (on the outside). The nitrogenous bases (adenine, thymine, cytosine, guanine) are on the inside and pair with bases on the complementary strand via hydrogen bonds. Option A is incorrect as bases are not the backbone. Option B is wrong because neither pyrimidines nor purines form the backbone. Option D is incorrect as the backbone is sugar - phosphate, not bases.

Answer:

C. Sugar - phosphate backbones with bases on the inside