I'm going to go out on a limb and assume you're asking if medical schools require you to have above a certain grade for pre-requisite classes, and your grade falls below the criteria set for one of those classes, will they eliminate you from consideration.
From what I know most schools require at least a C for the pre-reqs. If you found a school that requires a 2.5, which I can only assume is a C+, then I guess for that school you'd have to have a minimum of a C+. I'm not sure whether they would reject you outright, though.
You might want to consider either retaking the pre-req or at the very least, get an A in a more advanced class in the same subject area. You want to limit the number of C's you have in science courses, especially pre-reqs. Medical schools not only look at overall GPA, but they also consider your science/math GPA too (although I don't know why they include math considering you don't see any in med school).
One good thing about osteopathic medical schools is that they tend to give people another chance by how they calculate GPA. If you get an F, then replace it with an A, DO schools will throw out the F and replace it with the A in your GPA calculation (although the F will still be listed in your transcripts). MD schools include the F and the A into your GPA.