If a topic being passage based makes it unnecessary to study for, then technically you don't need to study for (almost) any section since nearly the whole test is passage based.
Just cross your fingers that your discrete questions are all on the topics you do study...
I don't know anything about your upper-division morphing class, but there is a list of recommended classes in the FAQ. Make it a priority to take your pre-reqs completely first, and then take classes like bio-chem, anatomy, etc. Noone knows what that class is like, so you are best off asking someone who took the class, but for sure it is not something you need.
If you are debating between taking a bio class and studying for the mcat bio, you are best off studying on your own since most college classes don't put an emphasis on preparing you for the MCAT, which is a whole different science in its own right. I just realized that was one freaken long sentence.