What's on the AP Biology exam comes down to eight units, two scored sections, and a few clear priorities. The exam does not weigh every topic the same, so your study time should not be split evenly either. In this guide, you will see the unit weight ranges, what the heavier units mean for your plan, and how the $5 AP Biology study guide and the $19 course line up with the test.
You will also see the May 3, 2027 exam date, what stayed the same for 2027, and where to use a free practice test and score calculator. If you are trying to spend less, or just keep prep simple, the numbers below make the choice easier.
The units on AP Biology, and how much they matter
If you are asking what's on the AP Biology exam, start with the unit weights. The table below shows all eight units and the share each one can take on the test. Those ranges matter because they tell you where more questions are likely to come from.
| # | Unit | Share of exam |
|---|---|---|
| 1 | Chemistry of Life | 8%–11% |
| 2 | Cells | 10%–13% |
| 3 | Cellular Energetics | 12%–16% |
| 4 | Cell Communication and Cell Cycle | 10%–15% |
| 5 | Heredity | 8%–11% |
| 6 | Gene Expression and Regulation | 12%–16% |
| 7 | Natural Selection | 13%–20% |
| 8 | Ecology | 10%–15% |
Do not read that table as eight equal boxes. They are not. Natural Selection carries the biggest range, 13%–20%. Two more units, Cellular Energetics and Gene Expression and Regulation, each sit at 12%–16%. Those three areas can take a large part of the exam, so they deserve more of your study time than a unit with an 8%–11% range.
That does not mean you should skip lower-weight units. Chemistry of Life and Heredity are still testable, and missed points still count. It means you should match your time to the weights. A simple way to do that is to spend your first passes on the heavier units, then tighten up the lighter ones.
The $5 study guide is built that way. It has one chapter per official unit, and it starts with the heaviest-weighted units first. That sounds small, but it saves time because it tells you what to study now, not just what exists on the outline.
What heavier units should mean for your study time
Unit weights are not just facts to memorize. They should change your calendar. If one unit can take up to 20% of the exam, and another sits at 8%–11%, you should not give both the same amount of time.
A smart split looks like this: start with Natural Selection, Cellular Energetics, and Gene Expression and Regulation. Then move to Cells, Cell Communication and Cell Cycle, and Ecology. Finish by cleaning up Chemistry of Life and Heredity. You are still covering everything, but you are putting more of your effort where the exam can draw more points.
The printable guide was built from the official units and weights, so the order already follows that logic. It is a 54-page PDF with 225 key terms, each with an example, 59 practice questions with every answer explained, common exam traps flagged, and a 2-page cram sheet for the night before. It also includes 2-, 4- and 8-week study plans built from the exam weights.
If you want to test yourself before you buy anything, use the free practice test. It has 25 original practice questions that follow the official course units and weights, and each answer comes with an explanation. That makes it a good way to spot weak units before you set your plan.
How the AP Biology exam is scored and structured
The AP Biology exam has two scored sections, and each one counts the same. Multiple choice is 50% of the score, and free response is 50% of the score. The table below gives the basic structure.
| Section | Questions or tasks | Share of score |
|---|---|---|
| Multiple choice | 60 questions | 50% |
| Free response | 6 tasks | 50% |
That even split matters. If you only drill multiple choice, you are preparing for half the score. If you only write free responses, same problem. Your prep should include both question types.
For May 2027, the official materials agree on these notes: the format is unchanged from 2026, the free-response section has a raw total of 34 points, and the official materials do not give per-question percentage weights inside the free-response set. So, you should not build a plan around rumors that one free-response type matters more than another by percent. Use the known facts instead: six free-response tasks, half the score, 34 raw points total.
AP scores run from 1 to 5. After practice, you can plug your raw section points into the free AP score calculator to see an estimated 1-5 score. It is an estimate, not an official conversion, but it helps you see if your multiple-choice work and free-response work are balanced.
The AP Biology study guide: $5, instant PDF
54 printable pages built from the official units, heaviest first: 225 key terms with examples, 59 practice questions with every answer explained, a 2-page cram sheet and 2-, 4- and 8-week study plans. Try 10 free sample questions on the page first.
See the AP Biology guide →What changed for the May 2027 exam
For AP Biology, the main May 2027 note is simple: the format stayed the same. The official exam page lists May 3, 2027, and the official course and exam description, AP Students page, and 2026 scoring guidelines all line up on the basic format. So if you are wondering what's on the AP Biology exam in 2027, the answer is not a redesign or a new section. It is the same eight units and the same two-section scoring split.
That is useful because it lowers the risk of using prep built around an older structure. You do not need to relearn a different format for 2027. You need to prepare for the same 60 multiple choice questions and 6 free-response tasks, with each section worth 50%.
This is also where the $19 AP Biology prep course stands out. It is built for the May 2027 exam. It includes 10 chapters, 64 lessons, 66 quizzes, and 18 interactive labs. It also has a timed final practice exam and a final exam, and each one includes a written part and a scoring guide.
If you want a wider view of AP subjects before you buy anything, the AP prep hub page shows the rest of the AP options. But for Biology, the key 2027 fact is steady format, not change.
How the $5 guide matches the exam
The $5 guide is the better fit if you want the fastest, cheapest way to cover the tested content in order. It is not an official material. It is built from the official units and weights, and that matters because AP Biology is not evenly balanced.
The guide gives you one chapter per unit, starting with the heaviest-weighted topics first. That mirrors how you should study. Instead of guessing what deserves the most time, the order does that work for you. Inside the PDF, you get 225 key terms with examples, 59 practice questions with every answer explained, common exam traps flagged, and the 2-page cram sheet for the night before. The built-in 2-, 4- and 8-week study plans are also based on the exam weights, which is more useful than a generic checklist.
This option also keeps the math simple. The $5 AP Biology study guide is a one-time purchase and an instant download. You can print it, mark it up, and use the 10 free sample questions on the guide page before buying.
Choose the guide if you mostly need structure, a weight-based order, and a low price. If you know you learn better from lessons, quizzes, labs, and fuller practice, the course may be worth the extra $14, since $5 plus $19 equals $24 for both.
When the $19 course makes more sense, and when a plan does
The course makes more sense when you want more than a summary and question set. It goes beyond a printable review by giving you 10 chapters, 64 lessons, 66 quizzes, 18 interactive labs, and two end-of-course exams, one timed final practice exam and one final exam, each with a written part and a scoring guide. That is useful if you need to relearn parts of the class, not just review them.
The $19 prep course is a paid-once option, so it is still pretty low-cost if AP Biology is the only subject you care about. Pairing it with the guide can work well too: use the guide to set priorities by weight, then use the course to practice those units in more detail.
Plans can make sense if you want more than AP Biology alone. AP Monthly is $29 a month and AP Lifetime is $149 once. Both include all 42 AP study guides and 36 AP prep courses. For one subject, a $5 guide plus a $19 course is $24 bought once. You can compare them on the plans and pricing page or go straight to the AP plans page.
One more budget note: AP exam fees are separate. In the U.S., U.S. territories, or Canada, the exam costs $99. Outside the U.S., it costs $129. Each college sets its own AP credit policy, so check your college before you register.
Frequently Asked Questions about AP Bio Exam Guide
There are eight units on the AP Biology exam: Chemistry of Life, Cells, Cellular Energetics, Cell Communication and Cell Cycle, Heredity, Gene Expression and Regulation, Natural Selection, and Ecology. The exam does not weigh them evenly, so your study time should not be even either.
Natural Selection is the heaviest at 13%–20%. Cellular Energetics and Gene Expression and Regulation are next at 12%–16% each. Those three units should get a bigger share of your time than units with an 8%–11% range, like Chemistry of Life and Heredity.
The exam has two scored sections. Multiple choice has 60 questions and counts for 50% of the score. Free response has 6 tasks and counts for the other 50%. For the free-response section, the official materials list a raw total of 34 points.
No format change is listed for May 2027. The official exam page lists May 3, 2027, and the official materials agree that the format is unchanged from 2026. That means the same eight units and the same split between multiple choice and free response.
Pick the $5 guide if you want a low-cost, printable review built around the unit weights. Pick the $19 course if you want lessons, quizzes, labs, and fuller practice. Buying both costs $24, which can make sense if you want both structure and deeper practice.
Maybe, but that is up to your college. AP scores run from 1 to 5, and each college sets its own policy for what score it accepts and what credit it gives. Check your college policy before you count on exam credit.
Final Thoughts on AP Bio Exam Guide
If you want the short version of what's on the AP Biology exam, it is this: eight units, uneven weights, and a 50-50 split between multiple choice and free response. Let those facts drive your prep. If you want the cheapest clear plan, start with the $5 study guide. If you want lessons, quizzes, labs, and final exam practice built for May 2027, add the $19 prep course. Your next step is simple: check the 10 sample questions on the guide page, then decide if the guide alone is enough or if you also want the course.
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