Isoprene is at the basis of a large class of biologically-relevant lipids known as terpenoids or isoprenoids. Isoprene is a five-carbon molecule with a single branch point (2-methyl-1,3-butadiene).
When multiple isoprene units are combined in the metabolic process they may lose their double bonds, but the branching is fairly characteristic of the group.
(a) How many isoprene units were incorporated in the following structure?