I didn't do the whole program but I took ochem there and most of my friends took all four basic bio courses. Here is the answer you're looking for and then the answer you need. The answer you're looking for is the classes take into account spectacularly poor performance, like the semester where almost everyone failed the ochem midterm and Logan had to adjust the grades. I also know the 2013 ochem II final's midterm average was 200/300 and not all of us got C's, so I am assuming we received some boost.
The answer you need is you shouldn't be applying to the program if your biggest concern is whether the class is graded on a curve. That says to me that you're not sure you can do the work and don't plan on stepping up to the plate. Instead, you're hoping you can hit the mean and take advantage of that. Not a good attitude, especially since you're going to be among boatloads of gunners who all have the same pre-health plan as you do.
Beyond that, the courses are hard but extensive, the program seems supportive of its students, and you get a committee letter. First, you need to make sure your priorities are in order.