biogen

{ } n. [ Gr. bi`os life + &unr_;, &unr_;, birth. ] (Biol.) (a) A doctrine that the genesis or production of living organisms can take place only through the agency of living germs or parents; -- called also biogeny; -- opposed to abiogenesis. (b) Life development generally. [ 1913 Webster ]

2. the production of a chemical compound by a living organism.
Syn. -- biosynthesis. [ WordNet 1.5 ]