What forms the backbone of DNA?

What forms the backbone of DNA?

• A. Base pairs
• B. Sugar and phosphate groups
• C. Lipids
• D. Proteins

Answer: (B)

DNA's backbone is the sugar-phosphate chain formed by deoxyribose sugars linked to phosphate groups through phosphodiester bonds. This repeating sugar-phosphate framework creates the exterior scaffold of the DNA molecule, running in a 5' to 3' direction, while the nitrogenous bases extend inward to pair with the complementary strand. The base pairs themselves are crucial for encoding genetic information, but they form the rungs of the ladder, not the backbone. Lipids and proteins are important for other cellular roles, but they do not constitute the DNA backbone.

DNA's backbone is the sugar-phosphate chain formed by deoxyribose sugars linked to phosphate groups through phosphodiester bonds. This repeating sugar-phosphate framework creates the exterior scaffold of the DNA molecule, running in a 5' to 3' direction, while the nitrogenous bases extend inward to pair with the complementary strand. The base pairs themselves are crucial for encoding genetic information, but they form the rungs of the ladder, not the backbone. Lipids and proteins are important for other cellular roles, but they do not constitute the DNA backbone.