The 2026 AP Biology Exam: Format and What Changed
The AP Biology exam for the 2025–26 school year is a hybrid digital format. Multiple-choice questions are viewed and answered digitally in the College Board's Bluebook app, while free-response answers are handwritten in paper booklets. This combination means you need to be comfortable working both on-screen and on paper during the same testing session.
The exam contains 60 multiple-choice questions and 6 free-response questions — 2 long-form and 4 short-form. Calculators are permitted throughout, including a four-function, scientific, or graphing calculator, and a reference sheet with equations and formulas is available in the app.
For the 2025–26 cycle specifically, College Board updated the AP Biology course framework in meaningful ways. Unit 1 was reorganized to reflect a more logical sequence of biological macromolecules. Content related to photosynthesis and cellular respiration in Units 2 and 3 was restructured for clearer concept engagement. Biogeochemical cycles were added to Topic 8.2, and redundant content was trimmed to offset the addition. If you are using study materials from before July 2025, verify they align with the updated framework.
AP Biology's 8 Units at a Glance
| Unit | Topic | Exam Weight (MCQ) | Key Focus Area |
|---|---|---|---|
| Unit 1 | Chemistry of Life | 8–11% | Water, macromolecules, carbon-based systems |
| Unit 2 | Cell Structure & Function | 10–13% | Organelles, membranes, homeostasis |
| Unit 3 | Cellular Energetics | 12–16% | Photosynthesis, cellular respiration, enzyme function |
| Unit 4 | Cell Communication & Replication | 10–15% | Signal transduction, cell cycle, mitosis |
| Unit 5 | Heredity | 8–11% | Mendelian genetics, meiosis, non-Mendelian inheritance |
| Unit 6 | Gene Expression & Regulation | 12–16% | DNA structure, transcription, translation, gene regulation |
| Unit 7 | Natural Selection & Evolution | 13–20% | Natural selection, Hardy-Weinberg, speciation, phylogenetics |
| Unit 8 | Ecology | 10–15% | Population dynamics, community ecology, biogeochemical cycles |
Units 3, 6, and 7 collectively account for roughly 37–52% of multiple-choice questions, making Cellular Energetics, Gene Expression, and Evolution the highest-leverage areas for focused study. Unit 7 alone can span 13–20% of the MCQ section — and free-response questions frequently use evolutionary reasoning as a scaffold for other biological topics.
Cells and Genetics: The Two Pillars of AP Bio Prep
Understanding Cellular Structure and Energetics
Units 2 and 3 form the mechanical foundation of the course. Students who grasp how cells are structured — the roles of the plasma membrane, mitochondria, chloroplasts, ribosomes, and the endoplasmic reticulum — are far better positioned to understand energetics, signal transduction, and even gene expression later in the year.
Cellular respiration is one of the most consistently tested processes on the AP Biology exam. Students must be able to trace a glucose molecule through glycolysis, the Krebs cycle, and the electron transport chain, accounting for ATP production at each stage and explaining the role of electron carriers like NADH and FADH₂. Photosynthesis, particularly the relationship between the light-dependent reactions and the Calvin cycle, appears equally often.
Genetics: From Mendel to Molecular
Unit 5 (Heredity) and Unit 6 (Gene Expression) together cover what most students think of as genetics. The Heredity unit starts with Mendelian inheritance — dominant and recessive alleles, monohybrid and dihybrid crosses, and the laws of segregation and independent assortment — and extends into non-Mendelian patterns including codominance, incomplete dominance, sex-linkage, and polygenic traits.
Unit 6 then connects heredity to the molecular level: the structure of DNA and RNA, the process of DNA replication, transcription (including promoter recognition, RNA polymerase, and mRNA processing), and translation (codons, anticodons, ribosomes, and the genetic code table). Gene regulation — including the lac operon in prokaryotes and chromatin remodeling in eukaryotes — is a consistent source of free-response material.
Common Pitfalls on the AP Biology Exam
- Confusing correlation with causation in data questions. AP Bio free-response questions frequently present experimental data and ask students to "describe" or "explain" results. Many students lose points by claiming a variable "caused" an outcome when the data only shows a relationship. Practice language like "as X increased, Y also increased" rather than "X caused Y."
- Memorizing without understanding. The AP Bio exam tests application, not recall. Knowing that the mitochondria produces ATP is not enough — you need to explain how the proton gradient generated by the electron transport chain drives ATP synthase through chemiosmosis.
- Neglecting evolution's role across units. Evolution is not just Unit 7. AP Biology embeds evolutionary reasoning into every unit. Questions about why cells share structural similarities, why genetic code is nearly universal, and why certain metabolic pathways are conserved across domains all reference evolutionary logic.
- Skipping the laboratory component. The AP Biology lab investigations — especially the ones on enzyme activity, osmosis, PCR, and gel electrophoresis — appear on the exam as data-analysis scenarios. Students who are unfamiliar with what these labs actually measure struggle disproportionately on the quantitative FRQs.
- Underestimating the reading load on FRQs. Long-form free-response questions on AP Biology often run 200–300 words of setup before the actual question. Slow or careless readers frequently misidentify the question being asked. Practice reading and annotating FRQ stems quickly.
How to Build an AP Bio Study Guide Using StudyGuidesAI
Here is the workflow that works best for AP Biology students using StudyGuidesAI. It takes about 15 minutes to set up and produces a study guide you can use for the rest of the school year.
First, gather your class notes organized by AP Bio unit. If your notes are messy or incomplete, grab your textbook's chapter summaries or a unit outline from your AP Classroom. Paste that content into the StudyGuidesAI generator, specify the unit and topic (for example, "Unit 3: Cellular Respiration — Calvin Cycle and Light Reactions"), and select the output format you want: structured notes, a concept map outline, a flashcard-ready glossary, or a set of practice questions.
The generated guide organizes your material into a hierarchy — Big Ideas at the top, unit themes in the middle, and specific content details at the bottom. This hierarchy mirrors the structure of the AP exam itself, which rewards students who can connect specific facts to broader biological principles. Generated flashcards from the same session make daily review ten minutes instead of an hour.
| StudyGuidesAI Output Type | Best Used For | When in Your Prep Cycle |
|---|---|---|
| Concept Summary Guide | Initial content review by unit | September – January |
| Flashcard Set | Daily vocabulary and term review | Ongoing throughout year |
| Practice Question Set | Active recall before unit tests | Before each unit exam |
| Exam Cram Guide | Full-course review synthesis | April – early May |
Turn Your AP Bio Notes Into a College-Credit Prep Guide
Paste any AP Biology unit's worth of notes and receive an organized, exam-ready study guide in under a minute. Free trial available — no account required to get started.
Generate My AP Bio Guide →Is Khan Academy Good for AP Biology Prep?
Khan Academy's AP Biology content is thorough and genuinely well-made, covering all 8 units with video lessons and practice questions. For visual learners, the animations on photosynthesis, DNA replication, and meiosis are particularly effective. The platform is completely free and tracks your progress over time.
That said, Khan Academy has real limitations for AP-level prep. Its practice questions tend toward the lower end of AP difficulty and do not replicate the data-analysis framing that defines modern AP Biology FRQs. It is best used early in the year for foundational content and supplemented with College Board's official AP Classroom resources, past FRQs from AP Central, and a personalized tool like StudyGuidesAI for custom guide generation as the exam approaches.