I am sorry but it depends on your school and the individual, don't take any one person's advice as fact. Here at UMDNJ it is notoriously one of the harder first year classes, especially since we have Biochem and Physio first in the fall and Anatomy and Micro in the spring. I feel that I would be having a much more difficult time with it if I hadnt taken it in undergrad. In fact, I would say biochem is the most valuable class to have taken in undergrad in preparation for medical school. Having seen the cycles, pathways, and enzymes before helps put it all in perspective when you are doing it for "real". (I say that because undergrad to me was always learning to get a good grade while in med school I feel like I am learning to understand). Anyway, my vote is taking it and pay attention.