Non-science major wanting to take science classes?

Hey guys!
I am an anthropology major and want to go to dental school. I was accepted as a transfer student and my concern is, how difficult is it for a non-science major to enroll into science classes? I need to take biology, physics and biochemistry. Just the core classes, and I know that lowest priority is given to the non-science majors. Is it impossible to enroll into the science classes? Would it help if I take summer classes? This is the main question that will decide whether I go to UCI or UCR.
Thanks!

There’s plenty of spots in the big lecture classes. The problem would be biology labs. UCI doesn’t have lower division bio labs, so you’ll have to take upper division labs to fulfill your requirements. These lab classes have tons of prerequisites and are usually full. Summer labs are full as well.