How important is senior year grades?

<p>I have 7 period of classes and 3 periods are taking AP classes. I have high grades in all of the classes, except my 2 AP classes. I can maybe get 80s for the final grade in AP chemistry, but I definitely won't pass the AP Calculus. If I only fail one class out of my 4 years of highschool, how bad will it affect my college admissions? Will colleges reject me for failing one class, but the other grades are high?</p>