Which of the following descriptions best fits the class of molecules known as nucleotides?

• A. Lipids consisting of glycerol and three fatty acids
• B. Polymers of amino acids linked by peptide bonds
• C. Simple sugars containing only carbon, hydrogen, and oxygen
• D. Molecules composed of a nitrogenous base, a five-carbon sugar, and one or more phosphate groups

Answer: (D)

Verified step by step guidance

1. Step 1: Begin by understanding the term 'nucleotide.' Nucleotides are the building blocks of nucleic acids, such as DNA and RNA. They consist of three key components: a nitrogenous base, a five-carbon sugar, and one or more phosphate groups.
2. Step 2: Analyze the options provided in the question. Each option describes a different class of biomolecules: lipids, proteins, carbohydrates, and nucleotides.
3. Step 3: Evaluate the first option, 'Lipids consisting of glycerol and three fatty acids.' Lipids are not nucleotides; they are hydrophobic molecules primarily involved in energy storage and membrane structure.
4. Step 4: Evaluate the second option, 'Polymers of amino acids linked by peptide bonds.' This describes proteins, which are composed of amino acids, not nucleotides.
5. Step 5: Evaluate the third option, 'Simple sugars containing only carbon, hydrogen, and oxygen.' This describes carbohydrates, which are monosaccharides or polysaccharides, not nucleotides. The correct description of nucleotides is the fourth option: 'Molecules composed of a nitrogenous base, a five-carbon sugar, and one or more phosphate groups.'