I got a C in general chemistry I. It is absolutely not a problem. I thought my life was over. I did better in chem 2, with a B. And after that I just rocked out all my other science classes. If you have a competitive GPA or other good grades in science, especially other chem type classes, the only schools that will even question it is the Ivy leagues. And if you do get a question, I feel like it is more to see how you will respond to it, were there any extraneous circumstances, and what you learned from that time period. Keep your head up, keep working hard, do well on your MCATs, and put the grade behind you (after you try to bump it up). You cannot change the past, so don't dwell on it and just put your energy into improving stuff that is in your power. I had no problem getting interviews or acceptances even with a C.