If you can retake the D and do well, as well as offer an explanation for your poor performance the first time around (death in the family, maybe a bad break up?) and your other grades are good, I don't think it would prevent you from getting in. I'd imagine going from a D in the pre-requisite to a B+ in the subsequent class would reflect somewhat positively, you must have had some serious catching up to do. (FYI I'm also a pre-med, so I don't know anything that you don't, but personally I wouldn't give up over it).