Minimum is 3.0 that honestly doesn't mean much as i just talked to my friend about it, the average student GPA there is much much higher.
I talked to a teacher at UC Merced and he said that you need at least a 3.0 to get in but i don't know about the test scores.
A Ph.D.
Yale Blue and California Gold.
3.5 and above for just any UC school, but some like Berkley and L.A. require 4.0 and above.