Which component of the DNA double helix forms the backbone of each strand?

• A. Nitrogenous base pairs
• B. Hydrogen bonds
• C. Amino acids
• D. Alternating sugar and phosphate groups

Answer: (D)

Verified step by step guidance

1. Recall the structure of the DNA double helix, which consists of two strands twisted around each other.
2. Identify the main components of each DNA strand: nitrogenous bases, sugar molecules, and phosphate groups.
3. Understand that the nitrogenous bases pair with each other via hydrogen bonds to form the rungs of the helix ladder.
4. Recognize that the sugar and phosphate groups alternate along each strand, forming a continuous chain.
5. Conclude that this alternating sugar-phosphate chain forms the backbone of each DNA strand, providing structural support.