What organic macromolecule is composed of nucleotides?

The correct answer is nucleic acid, which is indeed composed of nucleotides. Nucleotides are the building blocks of nucleic acids, which include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Each nucleotide consists of three components: a phosphate group, a five-carbon sugar (deoxyribose in DNA and ribose in RNA), and a nitrogenous base (which can be adenine, guanine, cytosine, or thymine in DNA, and uracil in RNA).

Nucleic acids serve essential functions in the storage and transfer of genetic information. DNA houses the instructions necessary for the development and functioning of living organisms, while RNA plays a critical role in translating these instructions into proteins, which are responsible for various cellular functions.

Other macromolecules like proteins, carbohydrates, and lipids have different structural units. Proteins are composed of amino acids, carbohydrates consist of monosaccharides, and lipids are primarily made up of fatty acids and glycerol. Understanding these distinctions is fundamental when studying biochemistry and molecular biology, as each class of macromolecule has unique roles in biological systems.