Welcome to science of things not fully yet understood.
It's worse: when you look at any software for "pretty well understood" chemistry, you'll find that of the code handling bonds, about 10% deals with the textbook kind of bonds, with electrons jumping orbitals and stuff. The other 90% handles all the other kinds that are special and don't fit into the textbook model of the atom as a tiny solar system. And every kind is different.
And then you make long polymer chains out of it and they bond into "secondary structures" and "tertiary structures", and when some of those chains decide to crawl forth and multiply... "not fully understood" my *ss. The best you can do is believe it because it doesn't make any sense.
</rant>
