The Advanced Placement Biology exam is an important exam for many high school students because it can give them a head start on earning college credit. This extra credit, however, is available only to students who score well on the exam and at colleges that accept it. Earning a high score requires understanding the types of questions that appear on the exam and the content that is tested.

Format of the Exam

The Advanced Placement Biology exam includes two large sections with different styles of questions. Section I contains multiple-choice questions, divided into two subsections. Part A includes 63 multiple-choice questions to assess students' general knowledge of the principles of biology and focuses on factual knowledge. Part B is shorter, with six "grid-in" questions that assess students' abilities to integrate science knowledge with mathematical abilities. The grid-in section requires students to write in numerical answers and then fill in numbered bubbles in the grid. In total, students have 90 minutes to finish both parts of Section I. Section II consists of two free-response subsections with two different types of questions: two "long" free-response and six "short" ones. In total, students get 90 minutes, including a 10-minute reading period, to complete all of Section II.

Content Tested on AP Biology

The content tested on the AP Biology exam is based on the College Board's biology curriculum framework. To simplify this framework, the College Board divides the curriculum into four main "big ideas": First, evolution drives the diversity and unity of life. Second, biological systems utilize free energy and molecular building blocks to grow, reproduce and maintain homeostasis. Third, living things store, retrieve, transmit and respond to information essential to life. Finally, students should understand the complex ways in which biological organisms interact. To be best prepared to answer the exam questions, students should be able to name concepts and facts that fall within these four big picture categories.

Free-Response Questions

While the multiple-choice and grid-in questions test students' factual and mathematical abilities, the free-response section supplements this to make sure students can integrate their knowledge and see the big picture. In addition, students are expected to go beyond mere biology knowledge and show an understanding of broader scientific methodologies. At least one of the free-response questions presents students with a hypothetical experiment or with an experiment's data and results. Students must interpret this information and make informed statements about the scientific method and how to use the experiment's results. To be prepared, students should be familiar with conducting and evaluating lab work.

Grading the Exam

Scoring is a critical part of any AP exam, because a good score often means that colleges and universities will award the student with some academic credit. The questions from Section I -- multiple-choice and grid-in questions -- are scored by a machine. The free-response questions, however, and read and graded by professionals and experts in biology. Once these two sections are graded, the raw scores are combined and converted to a 1 to 5 total score. The 5 score is designed to equate to an "A" grade in a college-level introductory biology class.

The College Board publishes past AP Biology exams so that students can practice taking the test and scoring their answers. In addition, several test-prep companies publish sample questions and answers so that students can simulate taking the test. In addition to learning the material, students' best bet for test preparation is to take sample tests under the same time restrictions as the official exam.