Shared Phosphate in Nucleotides

Steps:

• DNA consists of nucleotides with deoxyribose, phosphate backbone, and bases (A, T, C, G).
• RNA consists of nucleotides with ribose, phosphate backbone, and bases (A, U, C, G).
• ATP is adenosine triphosphate, featuring adenine, ribose, and a chain of three phosphate groups.
• The phosphate group links sugars and bases in DNA/RNA and forms the energy-carrying chain in ATP.

Why C is correct:

• Nucleotides, the building blocks of DNA and RNA, are defined by a phosphate group esterified to a sugar and base; ATP's formula (C₁₀H₁₆N₅O₁₃P₃) includes multiple phosphates for energy transfer.

Why the others are wrong:

• A. Adenosine (adenine + ribose) occurs only in A-based nucleotides of DNA/RNA and fully in ATP, not universally.
• B. Hydrogen bonds facilitate base pairing in DNA/RNA but are interactions, not structural components, and minimal in ATP.
• D. Ribose sugar is in RNA and ATP but replaced by deoxyribose in DNA.

Final answer: C