Which two molecules form the backbone of the DNA ladder?

• A. Deoxyribose sugar and nitrogenous bases
• B. Ribose sugar and nitrogenous bases
• C. Ribose sugar and phosphate
• D. Deoxyribose sugar and phosphate

Answer: (D)

Verified step by step guidance

1. Understand the structure of DNA: DNA is a double helix composed of two strands that form a ladder-like structure.
2. Identify the components of the DNA structure: The sides of the ladder are known as the backbone, and the rungs are composed of nitrogenous base pairs.
3. Recognize the components of the DNA backbone: The backbone is made up of alternating sugar and phosphate groups.
4. Differentiate between the types of sugars: DNA contains deoxyribose sugar, while RNA contains ribose sugar.
5. Conclude that the DNA backbone is formed by deoxyribose sugar and phosphate groups, not nitrogenous bases.