I went to a mid tier UC and did some of my courses at community college. I didn't have any extra credit opportunities in CC and I never knew what a curve was. Classes are very similar in the way material is taught between the two. The main difference is the way exams are made. At CC if you know the material you did well and the exam reflected that, no need to set a distribution. In university the professors deliberately make exams more difficult to distribute students. In the end they curve and boost everyones grade by a grade and a half (sometimes more) which is just really stupid for me. I wish they would instead write reasonable exams and allow that to distribute students. For the life of me I can't understand how a 40% is a B-. I thought CC was more difficult because if you messed up you didn't have leeway with a curve. Your raw score is your actual score. I'm not sure if CC's vary by state but the UC's are pretty strict in material/chapters overlapping the same way. We even used the same textbooks as the UC's (Bio, Ochem, Biochem). I would say the GE's might be really easy at community college but I've had science classes at my UC that are a walk in the park (Pathology class - no exams, just weekly summaries of what we learned, a take home final essay). Another class had averages of ~82% and still had a curve and extra credit. Another upper div bio had weekly quizzes that averaged out to >90% in the class. No exams, just one group project as a final.. safe to say everyone got A's and maybe a few B's.
If you do well on your MCAT then that can speak on how well you know the pre-req material (ochem, chem, bio).