AP Biology

Everything for the AP Biology exam: the eight course units, multiple-choice and free-response practice, and the math you need on exam day.

About the exam

Next exam3 May 2027

AP Biology is equivalent to a two-semester introductory college biology course. It runs from molecules and cells to evolution and ecology, and it tests science practices (designing experiments, analysing data, arguing from evidence) as much as content.

A score of 3 or higher can earn college credit or placement at many universities. Policies differ, so check the universities you are applying to.

Exam format

Section I: Multiple choice50%
60 questions, single or in sets of 4–5 based on one graph, table or experiment
Time: 90 min
Section II: Free response50%
6 questions: 2 long (9 points each) and 4 short (4 points each)
Time: 90 min

Section	Questions	Time	Share of score
Section I: Multiple choice	60 questions, single or in sets of 4–5 based on one graph, table or experiment	90 min	50%
Section II: Free response	6 questions: 2 long (9 points each) and 4 short (4 points each)	90 min	50%

Hybrid digital exam: you answer the multiple-choice questions and read the free-response questions in the Bluebook app, then handwrite your free-response answers in a paper booklet.

Units and exam weighting

Weighting is each unit's share of the multiple-choice section, as published by the exam board.

Unit 1: Chemistry of Life
Water and hydrogen bonding · Elements of life · Carbohydrates, lipids, proteins and nucleic acids · Structure and function of macromolecules
Unit guide 1 practice questions
8–11%
Unit 2: Cells
Cell structure and organelles · Surface area-to-volume ratio · Membrane structure and transport · Osmosis and water potential · Compartmentalization and endosymbiosis
1 practice questions
10–13%
Unit 3: Cellular Energetics
Enzyme structure and catalysis · Environmental effects on enzymes · Photosynthesis · Cellular respiration
1 practice questions
12–16%
Unit 4: Cell Communication and Cell Cycle
Cell signalling · Signal transduction · Feedback mechanisms · Cell cycle and its regulation
10–15%
Unit 5: Heredity
Meiosis and genetic diversity · Mendelian genetics · Non-Mendelian inheritance · Environmental effects on phenotype · Chromosomal inheritance
8–11%
Unit 6: Gene Expression and Regulation
DNA and RNA structure · Replication · Transcription and RNA processing · Translation · Regulation of gene expression · Mutations · Biotechnology
12–16%
Unit 7: Natural Selection
Natural and artificial selection · Population genetics and Hardy–Weinberg · Evidence of evolution · Phylogeny · Speciation and extinction · Origin of life
13–20%
Unit 8: Ecology
Responses to the environment · Energy flow through ecosystems · Population ecology · Community ecology · Biodiversity · Disruptions to ecosystems
10–15%

Question types and strategy

Multiple choice (60 questions)

Many questions come in sets built on one graph, table or experiment. Read the stimulus carefully once, then answer the whole set. There is no penalty for a wrong answer, so never leave a question blank.

Long free response (2 × 9 points)

Both ask you to interpret and evaluate experimental results; one also asks you to draw a graph. Label both axes with units, choose a sensible scale and plot error bars when the data give them.

Short free response (4 × 4 points)

One each on a scientific investigation, a conceptual question, a model or visual, and a data set. Each part is usually worth one point, so answer exactly what the task verb asks: identify, describe, explain, justify.

Calculations

A calculator is allowed and a formula sheet is provided. Expect Hardy–Weinberg, chi-square, water potential, rates and percent change. Show your setup and give units.