In DNA structure, which two molecules form the sugar-phosphate backbone of DNA?

• A. Phosphate groups and hydrogen bonds
• B. Ribose sugar and phosphate groups
• C. Deoxyribose sugar and nitrogenous bases
• D. Deoxyribose sugar and phosphate groups

Answer: (D)

Verified step by step guidance

1. Understand the structure of DNA, which consists of a long chain of nucleotides.
2. Each nucleotide is composed of three parts: a phosphate group, a sugar molecule, and a nitrogenous base.
3. The sugar in DNA is deoxyribose, which differs from ribose by lacking one oxygen atom.
4. The sugar-phosphate backbone is formed by covalent bonds between the phosphate group of one nucleotide and the deoxyribose sugar of the next nucleotide.
5. Hydrogen bonds connect the nitrogenous bases between the two DNA strands, but they do not form the backbone.