In the context of nucleic acids, ATP (adenosine triphosphate) is best classified as which type of biomolecule?

• A. A nucleotide (a nucleoside triphosphate)
• B. A triglyceride (triacylglycerol)
• C. A polysaccharide used for energy storage
• D. A polypeptide (protein)

Answer: (A)

Verified step by step guidance

1. Recall the four major classes of biomolecules: carbohydrates, lipids, proteins, and nucleic acids.
2. Understand that ATP (adenosine triphosphate) consists of an adenine base, a ribose sugar, and three phosphate groups.
3. Recognize that a molecule composed of a nitrogenous base, a sugar, and phosphate groups is classified as a nucleotide.
4. Note that ATP is specifically a nucleoside triphosphate because it has three phosphate groups attached to the nucleoside (adenosine).
5. Conclude that ATP is best classified as a nucleotide (a nucleoside triphosphate), not as a triglyceride, polysaccharide, or polypeptide.