How to study for AP Biology, from unit tests to the May 3, 2027 exam

What’s on the AP Biology exam in May 2027

The exam takes 3 hours, split into two halves that each count for 50% of your score.

The six free-response questions always come in the same order:

Four things to know before you start:

• It’s hybrid digital. You answer the multiple choice in College Board’s Bluebook app and read the free-response questions there, but you handwrite your free-response answers in a paper booklet.
• Graphing calculators are banned in 2027. You can bring a four-function calculator (with square root) or a scientific nongraphing one, or use the Desmos scientific calculator inside Bluebook. Plenty of guides, and even College Board’s own older course documents, still say graphing calculators are allowed.
• You get a formula sheet, with chi-square, Hardy–Weinberg, standard error, water potential, population growth and more. Practice using it, not memorizing it.
• There’s no penalty for guessing. Your multiple-choice score is the number you got right.

The exam is on Monday, May 3, 2027, in the afternoon session, which starts at 12 p.m. local time at most U.S. schools.

Which units matter most

These weights are for the multiple-choice section. College Board doesn’t publish unit weights for the free response, but each of the four short questions covers a different unit.

Unit 7 is the heaviest, and it also has the most topics. Units 3 and 6 come next. The deck at the end of this page covers Unit 7.

What to memorize and what to practice

Memorize with flashcards:

• Terms with their exact meaning. Gene versus allele, allele frequency versus phenotype, even protein versus proton: College Board’s own notes say students mix these up, and precise wording decides free-response points.
• Structure and function pairs. Students can name an organelle but not say what it does.
• The inputs, outputs and locations of pathways: photosynthesis, cellular respiration, fermentation.
• Process sequences: signal transduction, cell cycle checkpoints, transcription and translation.
• Definitions with conditions: the five Hardy–Weinberg conditions, the biological species concept, prezygotic versus postzygotic barriers.

Practice, because flashcards can’t do it for you:

• Designing experiments: variables, controls and null hypotheses.
• Building a graph from a table: axes, units, scale and error bars. It’s 4 of the 9 points on question 2.
• Reading data: trends, points, relationships.
• Calculations with the formula sheet: chi-square, Hardy–Weinberg, standard error, water potential.
• Claim, evidence and reasoning: the “predict and justify” parts appear in five of the six questions.

Why flashcards for the first list: practice testing and spaced practice were the only two of ten common techniques rated high utility in a major review, and rereading and highlighting were rated low (Dunlosky et al., 2013).

Testing beats rereading. In one well-known experiment, students who tested themselves on reading passages remembered 56% a week later, against 42% for students who restudied (Roediger and Karpicke, 2006).

What you can skip

College Board’s course description lists things that will not be on the exam. Students waste hours on them:

You also don’t need to memorize formulas; they’re on the sheet. Learn when to use each one.

How to study for an AP Bio unit test

1. Use the unit’s learning objectives in the course description as your checklist, and cross off anything on the skip list above.
2. Turn the unit’s key ideas into flashcards as you go, not the night before.
3. Review them in three or four short sessions spread across the week before the test.
4. Do the unit’s AP Classroom Progress Check, or one free-response question on the unit, under time.

Unit 1, the usual first test, covers:

• Water’s polarity and hydrogen bonding, and what they cause (cohesion, adhesion, surface tension).
• The elements in each macromolecule.
• Dehydration synthesis versus hydrolysis.
• The monomers and polymers of carbohydrates, lipids, nucleic acids and proteins, including the four levels of protein structure.

What exam readers marked down in 2025

Every year College Board publishes a report on how students answered. The 2025 report is a list of points students could have kept:

• The four short free-response questions averaged 1.7 to 2.0 points out of 4: half marks at best.
• Few students could justify an experimental control; many just called it “a baseline”.
• Students wrote the same thing for “provide evidence” and “justify the claim”. Evidence is what the data show; justification uses biology to explain why.
• Evolution answers used “phenotype” and “gene frequency” as if they meant the same thing. They don’t.

Watch out: “Ribosomes make amino acids” was one common error. They don’t; they link amino acids into proteins.

A plan from now to May 3, 2027

Short sessions spread over days beat one long session. A meta-analysis of 317 experiments found that spacing study across days, rather than cramming it into one sitting, is extremely useful for long-term memory (Cepeda et al., 2006).

The catch is doing the 15 minutes every day. That’s what prettysmart is for: it keeps the apps you pick locked until your due cards are done. If you’d rather use something else, we compared the best app blockers for studying and the best study apps for high school students.

Tip: Taking more than one AP exam? AP Psychology is on May 14 and AP U.S. History on May 7: see how to study for AP Psychology and how to study for APUSH.

If you have one week, or two days

One week out:

1. Order the units: 7, 3 and 6 first, then 4 and 8, then 1, 2 and 5.
2. Each day: review yesterday’s cards first, add one new unit’s cards, do one timed free-response question of a different type, and 15 mixed multiple-choice questions.
3. Day 6: one full timed section.
4. Day 7: review lightly and sleep.

Two days out:

1. Read the formula sheet once, so nothing on it is new on the day.
2. Learn the command words: identify, describe, explain, justify, and the difference between a claim, evidence and reasoning.
3. Do two or three short recall sessions on your Unit 7, 3 and 6 cards, hours apart, instead of rereading notes. In the same experiment as above, testing beat restudying even when the final test came two days later.
4. Nothing new the night before.

Self-studying AP Bio

You can take the exam without taking the course.

• Sign up through a school. Join an exam-only section with a code from the AP coordinator at the school where you’ll test. If your school doesn’t offer AP Biology, call another school’s coordinator early.
• Deadline and fee: schools order exams by November 13, 2026, and the exam costs $99 in the U.S.
• The hard part on your own is the free response, which is built on lab-style experimental design and data, so start the six question types early.

How AP Bio scores look