What is a nucleotide composed of?

A nucleotide is indeed composed of a phosphate group, a pentose sugar, and a nitrogenous base. This structure is fundamental to the formation of nucleic acids like DNA and RNA. The phosphate group contributes to the backbone of the nucleic acid structure, linking together the sugar molecules through phosphodiester bonds. The pentose sugar, which can be either ribose (in RNA) or deoxyribose (in DNA), provides the framework to which the nitrogenous base is attached. The nitrogenous base, which can be adenine, thymine, cytosine, guanine, or uracil, is crucial for coding genetic information and pairing with complementary bases during DNA replication and RNA transcription.

The other options contain components that are not part of a nucleotide's structure. Amino acids and glucose molecules do not comprise nucleotides; rather, amino acids are the building blocks of proteins, and glucose is a simple sugar that serves as an energy source. Carbohydrates and lipids are entirely different biomolecules with distinct roles in biological systems, and they do not combine to form nucleotides. Lastly, proteins and fatty acids do not relate to nucleotide composition in any direct way. Understanding the components of nucleotides is key