What is a Macromolecule?
The term macromolecule is used ambiguously to mean a molecule comprised of any “large number” of atoms, but more and more it is understood to mean only those molecules comprised of at least one-hundred atoms. Macromolecules may also be referred to less specifically as polymers. The bulk of macromolecules are found in biology and biochemistry, in the form of long protein chains and nucleic acids such as DNA. This class of molecules are sometimes referred to as biomacromolecules or biopolymers. It is rare to see a metal or crystal referred to as a macromolecule, even in cases where more than a hundred atoms are found linked together. More commonly the term is applied to plastics, where there are myriad examples of the type. Macromolecules are not simply an arbitrary distinction, as they do exhibit many physical properties that distinguish them from common molecules. One particularly interesting property is their inability to dissolve into solution without an outside assistance (in the fo
The literal definition of the term macromolecule implies any large molecule. In the context of science and engineering, the term may be applied to conventional polymers and biopolymers (such as DNA) as well as non-polymeric molecules with large molecular mass such as lipids or macrocycles. However, other large networks of atoms, such as metallic covalent networks or fullerenes, are not generally described as macromolecules. The use of the term macromolecule varies subtly from discipline to discipline. From the strict perspective of chemistry, a “molecule” comprises a number of atoms linked by covalent bonds. In biology and biochemistry, however, the term macromolecule may refer to aggregates of two or more macromolecules held together by intermolecular forces rather than covalent bonds but which do not readily dissociate. According to the recommended IUPAC definition the term macromolecule as used in polymer science refers only to a single molecule. For example, a single polymeric mole
