YoungJock:
I think it all depends. I took Bio. 1 and 2 as an undergrad and recieved a C and C+. I thought retaking them would be a waste of time.Instead, what I did was take some upper level biology courses and did well in them to show I know my Biology. I took Cell Biology in which I recieved a B, and Physiology in which I got a B+. I am taking Biochem. this spring, and Genetics next fall and am aiming to get a B or better in these 2 classes. So try and see if you can take some upper level Biology classes and do well in them to show you know your bio.,and take Biochem and get an A in it and show you have mastered Orgo.
Once again, this is just my own take on it. You may want to talk to your school's pre-med adviser.
Laavp