you can apply without having taken some of the pre-reqs but they must be done before school starts if you are accepted.
also, if you are missing many pre-reqs so that even if you try you will not be able to complete them by the time dent school starts you might not be accepted or even interviewed.
examle: i applied to ucla without having completed the psychology req. i got an interview before i took it, but during the interview the admissions person went over my pre-reqs and asked when I am planing on taking it. So i took it spring semester at a CC and now all my pre-reqs are done.
