Do what it takes to keep your GPA up
What people said earlier "GPA > MCAT > LOR = Research > Clinical experience > Other EC's"
Im sure moderators will come here and tell you otherwise, don't believe them.
If you successfully did a brain transplant and have a low GPA and MCAT computers screen out. The MCAT is a bit weirder now and is super catered to bio majors. Take courses you can balance and get A's and be the top of your class in, balance them in order to be able to manage your course load. In general you want Physiology, Cell + Molecular Biology, and base- biochemistry to go along in the MCAT, a light amount of biotechnology might help depending on the scenario, Organic Chemistry, the easiest set of physics you can take (believe me the MCAT physics is a joke), dont risk your grades by taking any physics higher than what your major requires, psych and sociology.