At my school,
For each class, Each quarter is 20% of the overall grade, while midterm and final grades are each 10% of the overall grade.
Today, I think that I messed up one my midterm exams. I most likely got a B or C. Will harvard, or any other college for that matter, care about this score? Or will they only care about the final grades in the classes? Or does it depend on what my school actually puts on the transcript?
All colleges, including Harvard, look at whatever grades are on your transcript that your guidance counselor sends them. As transcripts, and the grades they contain, vary from high school to high school, ask your GC what grades appear on your initial transcript and mid-year report. See: http://www.redlands.edu/docs/Admissions/2013MidYear_download.pdf
usually, you’re exam grades alone are not listed on your transcript. Your exam grade could however lower your course grade, and so yes, they will see a lower course grade than you had before you took the exam