Many professional degrees such as law, medicine, pharmacy, veterinary, dentistry, etc. are exclusively offered at UC’s and a student could start at a state school and study animal biology, but they would have be admitted into the program at Davis to become a vet.
And as noted above, the UC’s are research oriented. My husband teaches at Cal Poly, and they have an excellent physics program that would prepare a student for teaching high school physics or lab work. However, if a student wanted to get a doctorate in Physics and do research, it would be a mistake to go to Poly as a Bachelors degree in Physics from there would not help you get into the top graduate programs. Some programs are comparable to a UC, however, my husband got an electrical engineering degree from Cal Poly and went to Berkeley for his doctorate, his cousin got an Aerospace engineering degree from Cal Poly and went for his doctorate at Stanford.