I did exactly what you are talking about. I didnt have time to take all of my prereqs before graduating, so i graduated on time, but then took orgo in summer school at my undergrad. institution as an alumna (which was actually cheaper than being a student). after that, i moved home and took physics 1 and 2 in the fall and spring at a university in my home town...took the mcat in april, applied, and now will be starting in the fall. so it can definitely be done...it put 2 years between graduating and starting med school, but i appreciated the time off. i would have to agree with everyone else though and say that you should definitely take these classes at a reputable institution. but taking them after graduating shouldnt matter... and yes like someone else said, amcas calculates your gpa in the format they want, which includes post bac. classes, study abroad courses, transfer credits, etc., and they will require you to send them a transcript from every place you have taken course work so that they can verify it.