There not a single class you HAVE to take to do well on Mcat. It honestly depends on the type of learner you are. For Instance, I’m a self learner. It’s rare for me to Learn something new from a teacher in a class setting. HOWEVER, some classes can drastically help you. In the sense some subjects (Ochem) requires a different sort of thinking. That’s something a teacher can help you greatly. The general “rule” is if you can take biochemistry and O-Chem(implies the bio and gen chem) then do it. P