Which components make up the backbone of a DNA molecule?

• A. Nitrogenous bases and ribose sugars
• B. Amino acids and phosphate groups
• C. Alternating deoxyribose sugars and phosphate groups
• D. Deoxyribose sugars and nitrogenous bases

Answer: (C)

Verified step by step guidance

1. Recall the structure of a DNA molecule, which consists of a sugar-phosphate backbone and nitrogenous bases attached to the sugars.
2. Identify the sugar involved in DNA, which is deoxyribose, a five-carbon sugar lacking one oxygen atom compared to ribose found in RNA.
3. Understand that the backbone of DNA is formed by alternating units of deoxyribose sugars and phosphate groups linked by phosphodiester bonds.
4. Recognize that nitrogenous bases (adenine, thymine, cytosine, guanine) are attached to the deoxyribose sugars but are not part of the backbone itself.
5. Conclude that the correct components making up the backbone of DNA are alternating deoxyribose sugars and phosphate groups.