What Is AP Biology?
AP Biology is a College Board course on the principles of biology, from the chemistry of life and the workings of cells to genetics, evolution, and ecology. College Board gives its college equivalent as a two-semester introductory biology course for biology majors, and recommends high school courses in biology and chemistry beforehand.
The course has eight units. College Board publishes the share of the exam score that each one carries.
| Unit | What it covers | Share of exam score |
|---|---|---|
| 1. Chemistry of Life | Water as the basis of life and the functions of carbohydrates, lipids, nucleic acids, and proteins | 8% to 11% |
| 2. Cells | The makeup of cells and the structure and function of organelles | 10% to 13% |
| 3. Cellular Energetics | Enzymes, photosynthesis, and cellular respiration | 12% to 16% |
| 4. Cell Communication and Cell Cycle | How cells communicate and replicate | 10% to 15% |
| 5. Heredity | How traits pass from one generation to the next | 8% to 11% |
| 6. Gene Expression and Regulation | DNA and RNA, replication, transcription, translation, and biotechnology | 12% to 16% |
| 7. Natural Selection | Natural selection, population genetics, and the evidence for evolutionary change | 13% to 20% |
| 8. Ecology | How populations interact within communities and ecosystems | 10% to 15% |
The skills College Board names are designing experiments to test a prediction, collecting and analyzing data, interpreting data to draw conclusions, and supporting a scientific claim with evidence. Three of those four concern experiments and data.
Is AP Biology Hard?
On the 2026 exam, 71% of students scored 3 or higher and 15% earned a 5. About three students in ten scored below a 3.
| Year | 5 | 4 | 3 | 2 | 1 | 3 or higher | Test takers |
|---|---|---|---|---|---|---|---|
| 2026 | 15% | 25% | 31% | 21% | 8% | 71% | Not yet published |
| 2025 | 18.9% | 24.1% | 27.4% | 21.0% | 8.6% | 70.4% | 287,232 |
| 2024 | 16.8% | 23.1% | 28.4% | 21.7% | 10.0% | 68.3% | 260,062 |
| 2023 | 14.3% | 23.0% | 27.2% | 23.6% | 12.0% | 64.4% | 239,470 |
The share scoring 3 or higher has ranged from 64.4% to 71% since 2023, and the number of test takers grew from 239,470 in 2023 to 287,232 in 2025. The share earning a 5 was 18.9% in 2025 and 15% in 2026. Our guide to AP score distributions sets these results beside every other exam.
In our experience at Oriel Admissions, two things make the course demanding: the volume of material across eight units, and free-response questions that ask a student to interpret and evaluate the results of an experiment. A student who memorizes well but has had little practice with data tends to find the second part harder.
What Is on the AP Biology Exam?
College Board describes it as a hybrid digital exam. Students answer the multiple-choice questions and view the free-response questions in the Bluebook testing app, and handwrite their free-response answers in paper booklets. The exam lasts 3 hours.
| Section | Questions | Time | Share of score |
|---|---|---|---|
| Section I: Multiple choice | 60 | 1 hour 30 minutes | 50% |
| Section II: Free response | 6 (two long and four short) | 1 hour 30 minutes | 50% |
Calculators are permitted, and an equations and formulas sheet is available. The free-response section asks students to interpret and evaluate experimental results, graph and analyze data, and predict the causes or effects of a change in a biological system. The 2027 exam is on Monday, May 3, 2027. The length of every exam is listed in how long AP exams are.
In Which Grade Should a Student Take AP Biology?
College Board recommends high school biology and chemistry first, so a student who takes biology in 9th grade and chemistry in 10th grade has met both for 11th grade. Schools set their own rules, and the course catalog shows whether 10th graders may enroll.
At Oriel Admissions we plan the course for the first year after chemistry, because it opens with a unit called Chemistry of Life and College Board recommends chemistry beforehand. For a 9th grader the task is to take the strongest biology and chemistry courses the school offers in 9th and 10th grade, and to keep the grades high. Our guide to honors classes covers those two years, and the four year high school plan shows where the AP sciences fall.
Should a Student Take AP Biology or AP Chemistry First?
A student with room for one AP science in 11th grade has to choose. The two courses ask for different preparation: College Board recommends biology and chemistry before AP Biology, and chemistry and Algebra II before AP Chemistry.
In our view, the intended field should decide. A student heading toward biology, medicine, or public health can take AP Biology in 11th grade and AP Chemistry in 12th. A student heading toward engineering or the physical sciences is better served by AP Chemistry or AP Physics first. Our guide to AP courses for junior year sets out the choices by intended field.
What Do MIT, Caltech, and Yale Say About High School Biology?
MIT, Caltech, and Yale each publish what they expect, and none of the three asks for one particular AP science. MIT says that most students who are well prepared for it will have taken at least some physics, chemistry, and/or biology by the end of high school, and recommends at least introductory coursework across all three subjects if available. Once enrolled, every MIT student must take, or receive credit for, one semester of biology. Caltech requires one year of physics and one year of chemistry and lists one year of biology as recommended. Yale states that it does not prescribe a set of courses and looks for difficult coursework across a range of subjects, done well.
Biology is one subject among several in those statements. A student interested in medicine or the life sciences should plan chemistry, physics, and mathematics with the same care. The guides to the best colleges for pre-med and the best pre-med majors cover the college side, and BS/MD programs set expectations of their own.
Does AP Biology Earn College Credit?
Policies differ by college and by score. College Board gives the course equivalent as a two-semester introductory sequence for biology majors, but each college decides what a score is worth, and the AP Credit Policy Search shows the policy at each one. A student planning a biology major or a pre-med path should check whether the colleges on the list want the introductory sequence taken on campus.
For other courses, see our guides to AP Human Geography, AP World History, AP Seminar, AP Precalculus, AP Chemistry, AP Physics 1, and AP Computer Science Principles.
Frequently Asked Questions About AP Biology
It is demanding. On the 2026 exam, 71% of students scored 3 or higher and 15% earned a 5. The course covers eight units, and the exam asks students to analyze data and experiments.
College Board recommends high school courses in biology and chemistry.
That depends on the school. College Board recommends biology and chemistry first, so a 10th grader who has not yet taken chemistry has met only one of the two.
It lasts 3 hours. There are 60 multiple choice questions in 1 hour 30 minutes and 6 free response questions in 1 hour 30 minutes, and each section counts for half of the score.
The 2027 exam is on Monday, May 3, 2027.
Yes. College Board states that calculators are permitted, and an equations and formulas sheet is available.
Natural Selection carries the largest share, at 13% to 20% of the exam score. Cellular Energetics and Gene Expression and Regulation each carry 12% to 16%.
At Oriel Admissions we advise taking both where the school offers them. AP Biology in 11th grade and AP Chemistry in 12th grade is one sound order, and the reverse is another.
Sources: College Board: AP Biology course page, College Board: AP Biology Exam, College Board: AP Biology Score Distributions, 2023 to 2026, MIT Admissions: Academic foundations, Caltech: Academic Requirements for First-Year Applicants, Yale Undergraduate Admissions: Course Selection
About Oriel Admissions
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