The prerequisite coursework requirements vary tremendously from program to program. Unlike medical and dental school requirements, we simply can't make a concise list of exactly which classes one must take to apply to PA school.
Unfortunately, this is something that will take considerable time on your part to research. Some programs require little outside of anatomy and physiology, while others have 20+ required classes. The only way to determine which classes you need to take is to get on each school's website and peruse their prerequisite coursework.
Many schools require something like the following:
Anatomy with Lab
Physiology with Lab
Chemistry with Labs (includes inorganic and organic)
Psychology (1-3 classes)
Other biology classes (usually 2-3)
English (2 classes, must include freshman English/Writing)
Stastics (1 course through any department)
Not all programs will accept AP credit to fill their prerequisite requirements, so be sure to check with the program beforehand to see if you meet the requirement.
If you are planning on taking prerequisites after you submit your application, make sure that your schools are aware of this. However, if you can, it is better to complete your prerequisites before you apply, as pending prerequisites might be a strike against you.
Only rarely will a school waive a prerequisite course requirement, and this is generally only done in situations where the applicant has above-average work experience.