Yet another one of the infamous Advance Placement exams given by the College Board, the AP Biology exam covers an introductory, theoretically college-level course in, what else, Biology, with a one-shot exam in May. Like most of the AP's, it consists of two main parts:

    Section I: Multiple Choice

        120 Questions, 90 minutes, 60% of your grade.
   
    Section II: Essay

        4 Questions, 90 minutes, 40% of your grade.

Grading:

    Like the other Advance Placement exams, on a 1-->5 scale.
   Approximate Percentages:

Grade/Percentage of Students receiving grade
  1. 13%
  2. 22%
  3. 25%
  4. 21%
  5. 19%
What it covers:

  
It's divided into three broad categories, and then several smaller sub-categories:
  1. Molocules and Cell --> 25% of the test
  2. Genetics and Evolution  --> 25% of the test
  3. Organisms and Populations --> 50% of the test

Sub-Categories and Percentage of Test:

Note on the essay section:

It is important to note that the essay-grading scale, unlike the history AP's, is very objective and non-style oriented. Get your facts out, in clear, easy-to-see fashion, and include as much as you know about the subject. Oh, and on 3 out of 4 practice AP biology essays I've had, a Punnet Square got you some points, so throw one in there.

Sources: Coach Taylor's wonderful (haha) biology class notes and CliffsAP book, highly recommended.