Which term best describes a molecule of ATP?

• A. Polysaccharide
• B. Nucleotide
• C. Lipid
• D. Amino acid

Answer: (B)

Verified step by step guidance

1. Step 1: Begin by understanding the structure and function of ATP (adenosine triphosphate). ATP is a molecule that serves as the primary energy currency in cells, storing and transferring energy for various biological processes.
2. Step 2: Break down the components of ATP. ATP consists of three main parts: a nitrogenous base (adenine), a sugar molecule (ribose), and three phosphate groups. This structure is characteristic of nucleotides.
3. Step 3: Compare ATP to the given options. A polysaccharide is a carbohydrate made of many sugar units, which does not match ATP's structure. Lipids are hydrophobic molecules like fats and oils, which also do not match ATP's structure. Amino acids are the building blocks of proteins, and ATP is not a protein or composed of amino acids.
4. Step 4: Recognize that ATP fits the definition of a nucleotide. Nucleotides are the building blocks of nucleic acids (DNA and RNA) and consist of a nitrogenous base, a sugar, and phosphate groups, which aligns with ATP's structure.
5. Step 5: Conclude that the term 'nucleotide' best describes ATP based on its molecular structure and components.