Not even remotely. Nobody does. I remember upper-level classes where the professor would ask a question, and the entire class would collectively say, "Hmm, I vaguely remember maybe learning something about that; I think it has something to do with telomeres," but that was about it. Every once in a while someone would be able to cobble together a somewhat correct answer, but it was generally a group effort or just stuck in someone's head for some reason. I know there's some class of worms that has "-can-" in it's name somewhere from Freshman biology, but I can never remember the whole name, although if I mention that, someone else can occasionally dig up the entire word. Even for obvious stuff like mitosis, which we had had in grade school, high school, intro to bio, cell bio, and perhaps something else. We'd get to biochem and think, "Yeah, I remember the chromosomes line up and then move apart at some point, right? And there's something about crossing over, too, although any specifics elude me." Obviously there were some people who remembered a little better than others, but as far as retaining good, comprehensive knowledge of previous classes, no way.
As for the OAT, everybody has to restudy for that anyway.
