Prenylated proteins have side chains of these compounds.  Since beta-carotene is also a member of this class, its presence helps prevent the proteins from triggering cancer.  
Prenylated proteins have side chains of these compounds.  Since beta-carotene is also a member of this class, its presence helps prevent the proteins from triggering cancer.  Found in botanical oils, their structure of branched five-carbon units yields polymers such as gutta-percha and rubber.  For ten points, what compound's basic structural unit is C5H8, also known as isoprene.
Prenylated proteins have side chains of these compounds.  Since beta-carotene is also a member of this class, its presence helps prevent the proteins from triggering cancer.  
terpenes or isoprenoids