Can I get into a UC with a D first semester?

Okay here are the facts: My UC GPA is a 4.09. I have gotten straight As and four B’s in high school. My school is on a semester schedule where we receive one grade per semester. But right now I’m not doing so well in AP Calculus and I am almost at a D in the class. I’m going to try my hardest to bring that grade to a higher C at least but if I am not successful, will I get into a UC if i receive a D in Calc for my first semester? The UC I really wish to attend is UC Santa Barbara or Santa Cruz.

So, as per the minimum requirements for all UCs, a D will disqualify you from admission automatically. Do anything you can to get that D up to a C.

The D may or may not disqualify you should definitely email the schools because in the contract a D gives them the right to revoke your admission do anything you can to keep a C even if it means getting a tutor itll be worth it

Are you a Junior or a Senior? Is the D a quarter grade or will it be your semester grade? If you are a Senior, you are in jeopardy of losing any provisional admissions you may get unless you can get that grade up to a C. Find a tutor, talk to your teacher for extra credit, but do something to get that grade to at least a C for your semester grade.
If you are a Junior, the 2nd semester of an AP course with a C or higher grade will validate the D. Unfortunately the D will be factored into your UC GPA unless you repeat the exact class. UC’s are competitive schools, so having a D on your transcript will hurt your chances.