Oh and for 3i03, the course is mostly based on journal articles. They are pretty straight forward and the TAs explain the stuff in tutorial, so i would definately go.
As for 3v03, that course was hard...its got to be one of the most challenging Biology course I`ve taken - and I`ve taken a lot because I`m in the genetics specialization.
3v03 is a useful course but lots of hard work - 5 lab reports of about 15+ pages, 5 quizzes, 6 hours of lab per week and 1 hour of class and a final exam. During second semester I felt I was only studying 3V03 and never any other courses...I didn`t even have time to study for 3i03...but did well because its a very concept based course and not much memorization