Final answer:
Enzymes are not a component of nucleotides. Nucleotides are composed of a phosphate group, a sugar, and a nitrogenous base, while enzymes are proteins that act as catalysts in biochemical reactions.
Step-by-step explanation:
The part that is not a component of nucleotides is b. enzyme. Nucleotides are the building blocks of nucleic acids like DNA and RNA, and each nucleotide is made up of three parts: a phosphate group, a pentose sugar, and a nitrogen-containing base. These components can combine in different ways to form the nucleotides that then are assembled into the long chains of DNA or RNA. The phosphate group, the sugar, and the nitrogenous base like adenine, cytosine, guanine, thymine (in DNA), or uracil (in RNA) are crucial for the structure and function of nucleic acids. Enzymes, however, are proteins that catalyze biochemical reactions and are not a part of the nucleotide structure.