Fountain of Knowledge

I need to know something from those of you who are/were adept at things like getting good grades in school. High school, college, whatever. I was not what you would call an idea student (ie 2.6 GPA), so I'm not sure if my scenario is plausible or not.

First of all - would a college professor ever say that a final grade was based only on a final exam/essay, and not on coursework? He still assigns and grades the coursework to make sure the students are learning the material, but it doesn't count toward the final grade. Could that happen?

Second - If that was the case and you were a good student (straight A's, acedemic scholarship kind of student). Being the academic star you are, you've also got a full classload. You've got vast knowledge about the subject in question (as in, its your minor). Would you still do the coursework, or would you skip it?