For IR, I think it's good to know carbonyl, alcohol, aliphatic, N-H, and aromatics.
For NMR, I did get an NMR question and you need to have a pretty good idea about H' NMR, how splitting works and what generally is more or less downfield. This can be daunting, and it's most likely not going to be on your MCAT, but if you want to be fully prepared, I'd get some practice solving NMR problems.