Question

genes, chromosomes, and dna quick check
which answer choice below correctly describes the structure of dna? (1 point)
sugar-phosphate backbone with nitrogen bases coming off a single helix
sugar-nitrogen base backbone with phosphates in the middle forming a double helix
a sugar-phosphate backbone with nitrogen bases in the middle forming a double helix
nitrogen bases on the outside with sugar-phosphate in the middle of a double helix

Explanation:

DNA has a double - helix structure. The backbone is made of sugar (deoxyribose) and phosphate. The nitrogen bases (adenine, thymine, cytosine, guanine) are in the middle and form hydrogen bonds with their complementary bases.

Answer:

A sugar - phosphate backbone with nitrogen bases in the middle forming a double helix.