Prions are believed to cause some diseases, Mad Cow disease being one that comes to mind. Where the amino acids join, prions invade and use the mechanism to manufacture themselves.
Teleology there, what with "invading".. not that I wouldn't say that as well.
Yeh. I graduated in microbiology, but long ago, practiced in that and related fields for about fifteen years, and now read on some of this sporadically - all of it presently sort of a new subject to my brain with familiar words. Anecdotally, a friend of a friend died of Creutzfeldt Jakob disease.