AP Biology Study Hub
Use one focused loop: map the main ideas, take the practice test, then return to quick review and flashcards for the topics that need another pass.
Practice Test 1
Complete the timed practice form, then review every answer explanation.
- 60 source-backed questions
- 90-minute countdown after Begin Test
- Explanations shown after submission
Quick Review
Review the source-backed boxes before or after you take the practice test.
- 48 source-backed review boxes
- One popup study view
- Return to the hub after review
Flashcards
Use active recall to review the terms and ideas in this subject.
- 319 source-backed cards
- Search, filter, shuffle, and flip
- Mark known cards as you study
Study Blueprint
Find your current unit and choose a linked lesson before your next study block.
- 8 course units
- 74 topics linked below
- Open a lesson for guided practice
Practice Resources at a Glance
This study hub centers the timed practice form, then gives you the quick-review boxes and flashcards you need to repair missed concepts.
AP Biology Lessons
Choose a topic from your current unit. Each linked lesson includes explanations, a teaching video, and practice with answers. Some closely related topics share a lesson.
Unit 1: Chemistry of Life
- 1.1Water, Hydrogen Bonding, and the Properties Life Runs On
- 1.2Carbon Skeletons, Functional Groups, and the pH Scale
- 1.3From Monomers to Polymers: How the Four Families Are Built
- 1.4Carbohydrates: One Monomer, Many Jobs
- 1.5Lipids: The Family Defined by What Water Rejects
- 1.6Proteins: Sequence, Folding, and Structure-to-Function Argument
- 1.7Nucleic Acids, Directionality, and the Link to Unit 6
Unit 2: Cell Structure and Function
- 2.1Cell Theory, Two Kinds of Cells, and the Organelle Inventory
- 2.2Compartmentalization and the Endosymbiotic Origin of Organelles
- 2.3Surface Area, Volume, and the Limits on Cell Size
- 2.4The Fluid Mosaic Membrane
- 2.5Membrane Permeability: What Gets Through and What Does Not
- 2.6Transport Across Membranes: Gradients, Diffusion, and Osmosis
- 2.7Facilitated Diffusion: Channels, Carriers, and Saturation
- 2.8Active Transport, Pumps, and Bulk Transport
- 2.9Tonicity, Cell Volume, and Osmoregulation
- 2.10Water Potential: Predicting Water Movement with Numbers
Unit 3: Cellular Energetics
- 3.1Free Energy, Coupling, and Why ATP Is the Cell's Currency
- 3.2Redox, Electron Carriers, and the Shape of a Metabolic Pathway
- 3.3Enzymes: Active Sites, Kinetics, and Inhibition
- 3.4Temperature, pH, and the Limits of Enzyme Function
- 3.5Cellular Respiration and the ATP Ledger
- 3.6Inside the Matrix: Pyruvate Oxidation and the Krebs Cycle
- 3.7Electron Transport, the Proton Gradient, and Chemiosmosis
- 3.8Fermentation and the NAD⁺ Problem
- 3.9Photosynthesis: Pigments, Light, and the Thylakoid Reactions
- 3.10The Calvin Cycle: Turning Gas into Sugar
- 3.11Photorespiration and the C4 and CAM Adaptations
- 3.12Putting the Two Pathways Side by Side
Unit 4: Cell Communication and Cell Cycle
- 4.1Signal Types: Contact, Local, and Long Distance
- 4.2Reception, Transduction, and Response
- 4.3Inside the Pathway: Cascades, Branching, and Shutting Off
- 4.4Feedback: Loops That Hold Steady and Loops That Finish
- 4.5The Cell Cycle and Its Checkpoints
- 4.6Cyclins, Cdks, and the Machinery Behind the Checkpoints
- 4.7Mitosis, Cytokinesis, and Reading Cell-Cycle Data
- 4.8Reading Cell-Cycle Experiments
- 4.9When Cell-Cycle Control Fails
Unit 5: Heredity
- 5.1Meiosis Stage by Stage, and the Accounting That Goes With It
- 5.2Mitosis Versus Meiosis, Separated Once and For All
- 5.3Where the Variation Comes From
- 5.4Mendel's Laws, Crosses, and the Probability Rules
- 5.5Chi-Square: Testing a Genetic Hypothesis Against Real Counts
- 5.6Inheritance Patterns Mendel Did Not See
- 5.7Chromosomal Inheritance: Linkage, Nondisjunction, and Pedigrees
- 5.8The Environment Writes on the Phenotype
Unit 6: Gene Expression and Regulation
- 6.1DNA and RNA: The Molecules That Hold the Message
- 6.2DNA Replication, Enzyme by Enzyme
- 6.3Transcription and RNA Processing
- 6.4Translation and the Genetic Code
- 6.5Mutation: What Changes, and When It Matters
- 6.6Regulation of Gene Expression: Operons and Transcription Factors
- 6.7Gene Expression and Cell Specialization
- 6.8Viruses: Information That Borrows a Cell's Machinery
- 6.9Biotechnology: PCR, Gels, Plasmids, and CRISPR
Unit 7: Natural Selection
- 7.1Variation, Differential Reproductive Success, and Fitness
- 7.2Modes of Selection and the Cost of Attracting a Mate
- 7.3Artificial Selection: The Same Mechanism With a Chooser
- 7.4Drift, Gene Flow, and Mutation: The Other Three Mechanisms
- 7.5Hardy--Weinberg Equilibrium and How to Calculate With It
- 7.6Speciation and Reproductive Isolation
- 7.7Evidence, Phylogeny, and Reading a Tree
- 7.8Phylogeny: Reading Trees and Building a Cladogram
- 7.9Evolution Is Still Running: Variation, Extinction, and Change We Can Watch
- 7.10Variation in Populations: The Reserve a Species Draws On
- 7.11Origins of Life on Earth
Unit 8: Ecology
- 8.1Levels of Organization, Body Size, and the Cost of Being Alive
- 8.2Behavior as a Product of Natural Selection
- 8.3Energy Flow and the Cycling of Matter
- 8.4Population Growth, Carrying Capacity, and Limiting Factors
- 8.5What Applies the Brake: Density-Dependent and Density-Independent Regulation
- 8.6Community Interactions, Niches, and Succession
- 8.7Biodiversity: Richness, Evenness, and the Value of Redundancy
- 8.8Disruptions in Ecosystems
Study Blueprint
Follow the eight-unit sequence, or use a missed question to choose the lesson you need.
Chemistry of Life
7 topics with linked lessons above.
Cell Structure and Function
10 topics with linked lessons above.
Cellular Energetics
12 topics with linked lessons above.
Cell Communication and Cell Cycle
9 topics with linked lessons above.
Heredity
8 topics with linked lessons above.
Gene Expression and Regulation
9 topics with linked lessons above.
Natural Selection
11 topics with linked lessons above.
Ecology
8 topics with linked lessons above.
AP Biology spans 38 topics across four big ideas, from water chemistry and enzymes through genetics, evolution and ecosystem disruption. This hub follows the College Board unit order, pairs every topic with flashcards, and ends with a 60-question practice test whose explanations walk through the reasoning rather than just naming the answer.
Study path
- Map the main domains in the Study Blueprint.
- Take the practice test and read every explanation.
- Use Quick Review and Flashcards to repair weak spots, then retest.
The practice tools open in a focused study window so you can keep your place on this hub.
60 questions · 90 minutes
No timer is running on this screen. The countdown starts only after you select Begin Test.
Answer every question, then use the explanations to choose what to review next.