Do they weigh the courses you take in senior year heavily? Moreover, do they see your senior year grade? Is it okay to have 2-3 C’s out of 6 AP classes?
Senior rigor is considered in admissions but passing grades are required to maintain your provisional acceptance (3.0 Weighted for all UC’s except UCLA/UCB which require a 3.0 Unweighted GPA) and to make sure you meet all the a-g course requirements. If you are a borderline applicant, some UC’s may send you a supplemental review where they ask for 1st semester senior grades. Your best approach to Senior year is to maintain your current GPA and get no D’s or F’s which could result in you being rescinded.
UCSC says that your senior year grades need to be “consistent with your previous course work”. Unlike most other UCs, UCSC does not have an obvious “safe harbor” (like >= 3.0 GPA) if your senior GPA drops from your previous GPA.
http://admissions.ucsc.edu/apply/conditions-faq.html