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

• A. A nitrogenous base & a phosphate group.
• B. A nitrogenous base & a sugar.
• C. A nitrogenous base, phosphate group & a sugar.
• D. A nitrogenous base, a carbohydrate, & a sugar.

Answer: (C)

Verified step by step guidance

1. Understand the basic structure of a nucleotide: A nucleotide is composed of three components - a nitrogenous base, a phosphate group, and a sugar (specifically, a pentose sugar).
2. Identify the nitrogenous bases: These are organic molecules with a nitrogen atom that have the chemical properties of a base. Common examples include adenine, thymine, cytosine, guanine, and uracil.
3. Recognize the role of the phosphate group: The phosphate group is crucial for forming the backbone of the nucleic acid structure, linking the sugar of one nucleotide to the sugar of the next nucleotide.
4. Understand the sugar component: In nucleotides, the sugar is a pentose sugar, which can be either ribose (in RNA) or deoxyribose (in DNA).
5. Evaluate the options given in the problem: Compare each option to the known structure of a nucleotide, which includes a nitrogenous base, a phosphate group, and a sugar, to determine the correct description.