Here's the dealio.
It doesn't matter what university/college/online school you come from, the difference in the amount of information you'll be expected to absorb and retain for exams will exponentially increase from undergrad to here.
The difference is substantial enough that it's pretty much impossible to understand until you get here. I don't say this to say you didn't study in undergrad, I say this as a person who thought he studied a /lot/ in undergrad, was consistently at the top of classes, and thought it would be similar here.
Being completely honest here, if you would have shown me the information I would be expected to completely understand enough to apply to second and third order questions, I would have thought you were joking. I truly didn't know how much the human mind was capable of obtaining in such a short time before I got here.
The reasons I say studying at this point is useless are multiple.
1 - You can't really understand how much information you'll be expected to know until you get here, and the time you spend studying over the entire summer will probably equate to about a weeks worth when you get here. This isn't really an exaggeration at all, unless you literally plan on studying 80+ hours a week over the summer.
2 - Even if you do plan on studying 80+ hours, you're probably not going to be studying the right material. In a class of cell biology, anatomy, biochem, etc., there are about a billion things available to learn, and your profs will make pretty clear which million and a half they think are important. You'll wind up spending hours studying some stuff that never comes up in class.
3 - It's incredibly easy to get burnt out when you get here. After studying day in and day out for more hours than a full time job, week after week, for classes that don't even seem to relate to your eventual goal, the last thing you really want to do is to have started school already being tired of studying.
If you just absolutely have to study, the thing to do is to review information that you'll already be expected to know going in. DMU offered some primers of material for preparing students for biochem, anatomy terms, things like that. If you want to study, study things like that, otherwise you'll be studying things you don't need, not be studying enough, and spending some of your last few precious days that you don't have to be studying doing exactly that. I agree with flyhi here, that as far as studying goes, it wouldn't be terrible to review things you have a base in.
Even the differences in how I study from last semester to this one are substantial. Last semester I would think, "Oh no! just three days to study for 150 pages of biochem!" And we're not talking 150 easy pages, these are dense, and all material is open for testing.
Now, I think "Oh, thank God I've got these 2 days for 1000 slides in pathology, or I'd be in trouble".
Even on the exams that I performed the worst on, I have learned far more than I expected or thought possible. Your mind will be forced to adapt, and you will be pushed to the limits and be forced to find the fastest and most efficient ways to retain mass quantities of information.
It's like trying to prepare for playing basketball by reading a book. Yeah...you'll learn some stuff, but it doesn't really do a whole lot. You just have to play to figure it out.
Here's a hint, and maybe the most valuable piece of information I've learned here that I feel I should charge you for. Typing > writing. I used to write all my notecards out, until it started taking so long that I didn't have enough time to study them. Now I have a template on a word document, 4x2 squares double sided. One side the label, one side the info. I've exponentially increased my performance in studying and on exams.
Take that to the bank.