Which components make up the backbone of a DNA molecule?

• A. Phosphate groups and deoxyribose sugars
• B. Phosphate groups and nitrogenous bases
• C. Deoxyribose sugars and ribose sugars
• D. Nitrogenous bases and deoxyribose sugars

Answer: (A)

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 present in DNA, which is deoxyribose, distinguishing it from ribose found in RNA.
3. Understand that the backbone is formed by alternating phosphate groups and deoxyribose sugars linked together through phosphodiester bonds.
4. Recognize that nitrogenous bases (adenine, thymine, cytosine, guanine) are attached to the deoxyribose sugars but do not form the backbone itself.
5. Conclude that the components making up the backbone of DNA are the phosphate groups and deoxyribose sugars.