A nucleotide is comprised of which of the following?

A nucleotide is the basic building block of nucleic acids, such as DNA and RNA. Its structure consists of three fundamental components: a five-carbon sugar (either ribose in RNA or deoxyribose in DNA), a phosphate group, and a nitrogenous base (which can be one of four different bases: adenine, thymine, cytosine, or guanine in DNA, and adenine, uracil, cytosine, or guanine in RNA).

The sugar provides the structural framework, the phosphate group is essential for linking nucleotides together through phosphodiester bonds, and the nitrogenous base encodes genetic information. This combination allows nucleotides to participate in the formation of long chains, which are critical for the storage and transmission of genetic information.

Other options present components that do not correctly reflect the structure of a nucleotide. For instance, including amino acids, proteins, or lipids diverts from the established composition of nucleotides, reinforcing that only a sugar, a phosphate, and a base collectively define their structure.