Isoprenes

Part of speech: noun

Definitions

1. A class of hydrocarbon compounds characterized by a branched molecular structure and a fundamental unit consisting of five carbon atoms and eight hydrogen atoms
2. Organic molecules that serve as building blocks in the biosynthesis of various natural products, including terpenes and steroids
3. A group of compounds essential in various biological processes, recognized for their role in cellular signaling and as precursors to vital biomolecules

Etymology: The word "isoprenes" is simply the plural of "isoprene," the name of a five-carbon hydrocarbon. Its name is a misnomer, and that is the most surprising thing about it. In 1860, the British chemist C. G. Williams coined "isoprene" by combining three pieces: "iso-", meaning "equal" or "different, isomeric"; "pr(op)-", a three-carbon prefix; and "-ene", the suffix marking an alkene, a hydrocarbon with a carbon-carbon double bond. The name was meant to describe a molecule related to propene, a three-carbon alkene, but the compound Williams was studying actually has five carbons. The "pr" in the name points to the wrong chain length, so the word keeps a label that does not match the molecule it names.