What does macromolecule mean?
A macromolecule is a molecule of exceptionally large size, particularly one made from many repeating chemical units. The term is common in chemistry and molecular biology, where macromolecules include proteins, nucleic acids, carbohydrates, and lipids. Such molecules perform structural, informational, energetic, and catalytic roles in living organisms. Proteins, for example, form the working machinery of cells, while DNA and RNA store and transmit genetic information. The boundary between a macromolecule and a smaller molecule is not always sharply defined, and the word is often used more broadly than “polymer,” especially in biological contexts. Within polymer science, however, macromolecule generally emphasizes the large size of a substance composed of covalently connected repeating units. The term is distinct from “molecule” in general: every macromolecule is a molecule, but most molecules are not macromolecules.
nounA very large molecule, especially one composed of many repeating units. In biology, macromolecules include polymers such as proteins, nucleic acids, carbohydrates, and lipids.
- A chemical entity consisting of a very large number of atoms, especially a polymer composed of many repeating monomer units.
- In biology, a large organic molecule such as a protein, nucleic acid, carbohydrate, or lipid.
"The protein molecule folded into a complex three-dimensional macromolecule."
"The bacterium produced a defensive macromolecule that bound to the bacterial toxin."
"Researchers designed a synthetic macromolecule with unusual electrical properties."
Used when referring to multiple large molecular structures.
"Cellular membranes contain macromolecules that selectively control molecular transport."
Proteins, DNA, and carbohydrates are molecular machines whose work depends on every part of one enormous molecular structure.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does macromolecule come from?
Macromolecule combines the combining form macro-, from Greek makros, meaning “long” or “large,” with molecule, from the Latin diminutive of moles, meaning a mass or quantity of matter. The prefix helped emphasize molecules of unusually great size, while the compound became especially important in polymer chemistry and molecular biology. It shares its large-scale sense with words such as macroscopic, macrocosm, and macrocyte, which also derive from Greek makros.
Related word forms
How macromolecule is actually used
The term is primarily scientific and formal. Although it was once associated especially with polymeric substances, it is also used for large biological molecules whose structures are not necessarily simple chains of repeating units.
Easily confused with macromolecule
A molecule is any chemically bonded group of atoms, whereas a macromolecule is distinguished by its very large size and often its polymeric structure.