God I agree. Unit 1 and 2 chem is pretty crucial for unit 3 and 4, specifically for redox, stoichiometry, chem calculations, moles, organic chem, etc. I've heard of people doing it, but I really wouldn't recommend it. I've personally found chem hard enough this year, even though I've done all the units, and units 1 and 2 have been a massive help. There is an overlap with food chem and enzymes/proteins in bio, but you don't need to do bio for this chem content to make sense (and if anything, it can be problematic because certain phrases and words are not interchangeable between each subject). Bio isn't all that helpful for chem (I'd honestly say that I've found chem to be more helpful for bio).
