The five-carbon hydrocarbon molecule: 2-methyl-l,3 butadiene. It is a recurring structural unit of the terpenoid molecules, which are either linear or cyclic. There exists a very large number of terpenes and many are major components of essential plant oils.
A five-carbon unit used in the synthesis of sterols.
A volatile hydrocarbon produced naturally by plants and animals and used in industry to make synthetic rubber and many copolymers. In humans it is involved in mevalonate and therefore cholesterol synthesis. Industrial exposures to high levels of isoprenes are toxic and potentially carcinogenic.