Question: My child's high school gives quarter and semester grades. Do colleges just look at just the end-of-semester grades or at all grades?
Most high schools put all grades on the transcript that goes to colleges; some high schools, however, will put only the final grade for each course. (For half-year classes or Block System classes, this is usually the semester grade. At schools with four quarters per class or three trimesters, it will be the cumulative grade for that class, as determined by the teacher at the end of the year.)
Assuming that all grades, not just the final ones, are indeed on the transcript, then college admission officials will look at them but they won't really "use" them except sometimes as potential puzzle pieces ... i.e., to help them to discern patterns or problems. For instance, if an A student ends the year with several B's, the admission committee may notice that he or she had one disastrous quarter (C's, D's, maybe even an F) and A's in all the others. If concerned, an admission officer might call the school to get more information about why that student slipped so much in that single term (Illness? Family crisis? etc.)
Occasionally, seeing the quarter grades may raise some flags. If a student is bouncing all over the place with up and down marks in every subject, the college folks may question this candidate's focus and work ethic.
More typically however, the grades don't vary egregiously from quarter to quarter. So if a "B" student has a "C" in one marking period, the admission committees will barely give this a second glance, and the focus will really be just on the final grade.
Hope that answers your question. Be sure to check with your child's school so that you'll know what the colleges will ... and won't ... actually see on the transcript.