For the long term, general knowledge and understanding would be great, but you will learn all that in med school (I presume they will tech it the way they want to).
I took the MCATs without ever taking a biology course (not even intro). I DO NOT RECOMMEND THIS, nor am I being cocky. I am a non trad and that is just the way the schedules worked out so I could work and still take night classes. That being said, I got an 8 in the Biological Sciences portion (not great, but it got me in).
The reason I mention my own situation is that I truloy studied my tail off since I had no BIO. I used Examkrackers complete set of books (no class was offered) and supplimented it with audio Osmosis from EK and took a all the practice exams that were available.
so, IMHO, I would spend the time prepping for the MCATs rather than a BIO class. If you feel the need, I have been told by just about anyone, that biochem would be the best for your first year of med school (not necessarily the mcats).
sorry for the ong post, but hope I added value. Best of luck.