THC is biochemically synthesized in the Cannabis genera of plants. But I suppose you already know that. GGP (see below) is a very common precursor in plant biosynthesis. This chart gives the steps and necessary enzymes. read more
Although Cannabidiol (CBD) has no psychoactivity, it does antagonize THC and produces other valuable sedative, antibiotic, and anti-epileptic effects. CBD can be isomerized to THC. If the plant is Phenotype III (containing mainly CBD in its resin), isomerization can double the yield of THC. read more