I never had time for biochem as an undergrad but knew it would be helpful for med school. I am taking it now and LOVE IT. It is so human based. We go over stuff and then relate it all back to the human body and what things do, how things are affected, etc... I would highly recommend it.
Now that said.... I would HIGLY recommend taking from a non-chemistry professor unless chemistry is your major. Biology profs teach this class sooooo much better and you get more out of the class that can be helpful in your MSI year. Our instructor is awesome!!!! It brings together ALL the things I have larned in 4 years of being a bio major and clears up a whole bunch of things.
Like I never knew that there were more than 20 amino acids. I thought that was all. Now I know differently. You find out what the Omega 3 and 6 stand for (the last C in the lipid chain is named the "omega carbon). I had heard about how important the Omega 3's are for you diet, but I had no idea what this was talking about, until now.
There is a lot of work, but no more than most upper level science courses. Plus med school is lot of work thrown at you all at once, so you might as well get some practice in.
Oh, and I might mention i have a lot of friends who are now MSII and they recommend 2 course to take BEFORE med school
1) Biochem (biology based and taught)
2) Histology