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.
Use this study hub as a simple loop: start with the quick review, take the practice test, then return to the flashcards for the ideas that need another pass.
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.