AP Biology
Self-paced lessons — an introduction plus 126 lessons · 2125 ideas · 1262 questions. Work through at your own rate; each
part ends with a check you must pass to move on.
Introduction · Life at every scale What biology studies, and at what scales 11 ideas · 3 parts · 2 questions Zooming in on a living thing: cells, molecules and atoms 28 ideas · 5 parts · 8 questions Zooming out from one organism: populations, communities and ecosystems 19 ideas · 4 parts · 8 questions The four questions AP Biology asks at every level 26 ideas · 4 parts · 7 questions Unit 1 · Chemistry of Life Topic 1.1 · Structure of Water and Hydrogen Bonding Bonds and partial charges 27 ideas · 6 questions The hydrogen bond 23 ideas · 8 questions Water sticks to itself and to other things 21 ideas · 8 questions Slow to warm 16 ideas · 6 questions Cooling by evaporation 23 ideas · 6 questions How AP Biology asks you questions Four options, one answer 14 ideas · 4 questions What the verb is asking for: Describe, Explain, Predict 28 ideas · 10 questions What the verb is asking for: Justify, Identify, Represent 26 ideas · 8 questions How a point is earned 29 ideas · 8 questions A free-response question, step by step 13 ideas · 2 questions Topic 1.1 · Structure of Water and Hydrogen Bonding (continued) End-of-topic test: Structure of Water and Hydrogen Bonding 16 multiple choice · 2 free response Topic 1.3 · Introduction to Biological Macromolecules Chains: build and break 21 ideas · 7 questions Counting the water 29 ideas · 16 questions End-of-topic test: Introduction to Biological Macromolecules 16 multiple choice · 2 free response Topic 1.4 · Carbohydrates One sugar, many chains 20 ideas · 7 questions Starch, glycogen and cellulose 15 ideas · 5 questions End-of-topic test: Carbohydrates 16 multiple choice · 2 free response Topic 1.5 · Lipids Why oil and water don't mix 24 ideas · 6 questions Butter or olive oil 28 ideas · 9 questions Fats and steroids 24 ideas · 16 questions The membrane around every cell 28 ideas · 9 questions End-of-topic test: Lipids 16 multiple choice · 2 free response Topic 1.6 · Nucleic Acids One strand of DNA 37 ideas · 8 questions The second strand 23 ideas · 15 questions Antiparallel, and DNA versus RNA 21 ideas · 11 questions End-of-topic test: Nucleic Acids 16 multiple choice · 2 free response Topic 1.7 · Proteins: Structure and Function Inside one amino acid 26 ideas · 5 questions From amino acids to a chain 21 ideas · 6 questions Folding 26 ideas · 7 questions Shape is the job 29 ideas · 7 questions End-of-topic test: Proteins: Structure and Function 16 multiple choice · 2 free response Topic 1.2 · Elements of Life Where the atoms in you come from 27 ideas · 8 questions End-of-topic test: Elements of Life 16 multiple choice · 2 free response Unit 2 · Cells Topic 2.3 · Plasma Membrane Two watery worlds and the film between them 28 ideas · 9 questions A mosaic that flows 20 ideas · 7 questions End-of-topic test: Plasma Membrane 15 multiple choice · 2 free response Topic 2.4 · Membrane Permeability What gets through the hydrophobic interior 34 ideas · 10 questions Topic 2.5 · Membrane Transport A drop of dye spreads 35 ideas · 10 questions Topic 2.6 · Facilitated Diffusion Doors for ions and sugars 35 ideas · 12 questions End-of-topic test: Facilitated Diffusion 14 multiple choice · 2 free response Topic 2.8 · Mechanisms of Transport Pumping uphill 21 ideas · 4 questions Why the inside of a cell is negative 24 ideas · 8 questions End-of-topic test: Mechanisms of Transport 15 multiple choice · 2 free response Topic 2.5 · Membrane Transport (continued) Too big for any door 23 ideas · 7 questions End-of-topic test: Membrane Transport 15 multiple choice · 2 free response Topic 2.7 · Tonicity and Osmoregulation Red cells in three beakers 32 ideas · 8 questions Topic 2.4 · Membrane Permeability (continued) Why celery goes limp 28 ideas · 10 questions End-of-topic test: Membrane Permeability 15 multiple choice · 2 free response Topic 2.7 · Tonicity and Osmoregulation (continued) Keeping water in balance 19 ideas · 4 questions Water potential: a number for which way water goes 23 ideas · 16 questions Solute potential from a concentration 27 ideas · 20 questions The potato lab 20 ideas · 18 questions End-of-topic test: Tonicity and Osmoregulation 16 multiple choice · 2 free response Topic 2.2 · Cell Size Why a cell can't just grow bigger 29 ideas · 19 questions Bigger bodies, folded surfaces 35 ideas · 21 questions End-of-topic test: Cell Size 15 multiple choice · 2 free response Topic 2.1 · Cell Structure and Function Two kinds of cell 38 ideas · 10 questions Make and ship 39 ideas · 8 questions Three cells, three jobs 38 ideas · 10 questions End-of-topic test: Cell Structure and Function 16 multiple choice · 2 free response Topic 2.9 · Cell Compartmentalization Rooms with their own rules 26 ideas · 7 questions End-of-topic test: Cell Compartmentalization 14 multiple choice · 2 free response Topic 2.10 · Origins of Cell Compartmentalization The cell that moved in 26 ideas · 7 questions End-of-topic test: Origins of Cell Compartmentalization 14 multiple choice · 2 free response Unit 3 · Cellular Energetics Topic 3.1 · Enzymes The fizz on a cut 32 ideas · 18 questions Used again and again 17 ideas · 6 questions Why catalase ignores sugar 22 ideas · 19 questions Potato or liver? Designing a fair test 23 ideas · 8 questions End-of-topic test: Enzymes 16 multiple choice · 2 free response Topic 3.2 · Environmental Impacts Warm the tube 27 ideas · 17 questions Too sour, too bitter: pH 18 ideas · 14 questions Sometimes the fold comes back 16 ideas · 4 questions More substrate, more product? 19 ideas · 6 questions Blocking the door, or bending the frame 29 ideas · 5 questions Ten tubes, one number 20 ideas · 18 questions How sure are you? 37 ideas · 23 questions End-of-topic test: Environmental Impacts 16 multiple choice · 2 free response Topic 3.3 · Cellular Energy How a cell pays for work 29 ideas · 8 questions Order costs energy 24 ideas · 8 questions One big step or dozens of small ones 23 ideas · 6 questions End-of-topic test: Cellular Energy 16 multiple choice · 2 free response Topic 3.5 · Cellular Respiration Where sugar’s energy goes 36 ideas · 8 questions From glucose to carbon dioxide 27 ideas · 8 questions Downhill electrons, uphill protons 34 ideas · 8 questions Break the machine and see 21 ideas · 6 questions When oxygen runs out 20 ideas · 16 questions Graph the yeast 25 ideas · 20 questions End-of-topic test: Cellular Respiration 15 multiple choice · 2 free response Topic 3.4 · Photosynthesis Where a tree’s mass comes from 29 ideas · 8 questions A plant in a sealed jar, day and night 16 ideas · 11 questions Inside a chloroplast 34 ideas · 18 questions One electron’s journey 33 ideas · 6 questions Building sugar in the stroma 24 ideas · 14 questions One machine, one ancestry 27 ideas · 5 questions End-of-topic test: Photosynthesis 17 multiple choice · 2 free response Unit 4 · Cell Communication and Cell Cycle PLACEHOLDER ONLY · DEMO COMING SOON · NOT READY FOR REVIEW Cell Communication 21 ideas · 5 parts · 10 questions Introduction to Signal Transduction (part 1 of 3) 15 ideas · 2 parts · 10 questions Introduction to Signal Transduction (part 2 of 3) 15 ideas · 1 parts · 10 questions Introduction to Signal Transduction (part 3 of 3) 14 ideas · 1 parts · 10 questions Signal Transduction Pathways 20 ideas · 5 parts · 10 questions Feedback 21 ideas · 2 parts · 10 questions Cell Cycle (part 1 of 3) 21 ideas · 2 parts · 10 questions Cell Cycle (part 2 of 3) 21 ideas · 2 parts · 10 questions Cell Cycle (part 3 of 3) 11 ideas · 1 parts · 10 questions Regulation of Cell Cycle 14 ideas · 4 parts · 10 questions Unit 5 · Heredity PLACEHOLDER ONLY · DEMO COMING SOON · NOT READY FOR REVIEW Meiosis (part 1 of 4) 19 ideas · 1 parts · 10 questions Meiosis (part 2 of 4) 19 ideas · 1 parts · 10 questions Meiosis (part 3 of 4) 19 ideas · 1 parts · 10 questions Meiosis (part 4 of 4) 16 ideas · 2 parts · 10 questions Meiosis and Genetic Diversity (part 1 of 2) 16 ideas · 2 parts · 9 questions Meiosis and Genetic Diversity (part 2 of 2) 14 ideas · 1 parts · 10 questions Mendelian Genetics (part 1 of 2) 22 ideas · 2 parts · 10 questions Mendelian Genetics (part 2 of 2) 19 ideas · 1 parts · 10 questions Non-Mendelian Genetics (part 1 of 4) 19 ideas · 2 parts · 10 questions Non-Mendelian Genetics (part 2 of 4) 19 ideas · 1 parts · 10 questions Non-Mendelian Genetics (part 3 of 4) 19 ideas · 1 parts · 10 questions Non-Mendelian Genetics (part 4 of 4) 10 ideas · 1 parts · 10 questions Environmental Effects on Phenotype 15 ideas · 1 parts · 10 questions Unit 6 · Gene Expression and Regulation PLACEHOLDER ONLY · DEMO COMING SOON · NOT READY FOR REVIEW DNA and RNA Structure (part 1 of 2) 18 ideas · 2 parts · 10 questions DNA and RNA Structure (part 2 of 2) 17 ideas · 3 parts · 10 questions DNA Replication (part 1 of 2) 12 ideas · 2 parts · 10 questions DNA Replication (part 2 of 2) 11 ideas · 1 parts · 10 questions Transcription and RNA Processing (part 1 of 2) 19 ideas · 2 parts · 10 questions Transcription and RNA Processing (part 2 of 2) 18 ideas · 1 parts · 10 questions Translation (part 1 of 2) 20 ideas · 2 parts · 10 questions Translation (part 2 of 2) 17 ideas · 1 parts · 10 questions Regulation of Gene Expression (part 1 of 2) 18 ideas · 2 parts · 10 questions Regulation of Gene Expression (part 2 of 2) 17 ideas · 3 parts · 10 questions Gene Expression and Cell Specialization 18 ideas · 4 parts · 10 questions Mutations (part 1 of 3) 21 ideas · 2 parts · 10 questions Mutations (part 2 of 3) 20 ideas · 4 parts · 10 questions Mutations (part 3 of 3) 20 ideas · 3 parts · 10 questions Biotechnology (part 1 of 2) 14 ideas · 2 parts · 10 questions Biotechnology (part 2 of 2) 12 ideas · 1 parts · 10 questions Unit 7 · Natural Selection PLACEHOLDER ONLY · DEMO COMING SOON · NOT READY FOR REVIEW Introduction to (part 1 of 2) 16 ideas · 1 parts · 10 questions Introduction to (part 2 of 2) 14 ideas · 2 parts · 10 questions Natural Selection 19 ideas · 3 parts · 10 questions Artificial Selection 6 ideas · 1 parts · 10 questions Population Genetics (part 1 of 2) 14 ideas · 2 parts · 10 questions Population Genetics (part 2 of 2) 13 ideas · 3 parts · 10 questions Hardy-Weinberg Equilibrium (part 1 of 2) 18 ideas · 2 parts · 10 questions Hardy-Weinberg Equilibrium (part 2 of 2) 11 ideas · 3 parts · 10 questions Evidence of Evolution (part 1 of 2) 18 ideas · 3 parts · 10 questions Evidence of Evolution (part 2 of 2) 14 ideas · 1 parts · 10 questions Common Ancestry 10 ideas · 2 parts · 10 questions Continuing Evolution 17 ideas · 2 parts · 10 questions Phylogeny (part 1 of 2) 17 ideas · 2 parts · 10 questions Phylogeny (part 2 of 2) 15 ideas · 2 parts · 10 questions Speciation (part 1 of 2) 19 ideas · 2 parts · 10 questions Speciation (part 2 of 2) 17 ideas · 2 parts · 10 questions Variations in Populations 21 ideas · 2 parts · 10 questions Origins of Life on Earth 17 ideas · 2 parts · 10 questions Unit 8 · Ecology PLACEHOLDER ONLY · DEMO COMING SOON · NOT READY FOR REVIEW Responses to the Environment (part 1 of 4) 18 ideas · 2 parts · 10 questions Responses to the Environment (part 2 of 4) 18 ideas · 3 parts · 10 questions Responses to the Environment (part 3 of 4) 18 ideas · 2 parts · 10 questions Responses to the Environment (part 4 of 4) 12 ideas · 3 parts · 10 questions Energy Flow Through Ecosystems (part 1 of 6) 22 ideas · 2 parts · 10 questions Energy Flow Through Ecosystems (part 2 of 6) 22 ideas · 4 parts · 10 questions Energy Flow Through Ecosystems (part 3 of 6) 22 ideas · 2 parts · 10 questions Energy Flow Through Ecosystems (part 4 of 6) 22 ideas · 4 parts · 10 questions Energy Flow Through Ecosystems (part 5 of 6) 22 ideas · 5 parts · 10 questions Energy Flow Through Ecosystems (part 6 of 6) 20 ideas · 3 parts · 10 questions Population (part 1 of 2) 20 ideas · 2 parts · 10 questions Population (part 2 of 2) 13 ideas · 2 parts · 10 questions Effect of Density on Populations (part 1 of 2) 13 ideas · 4 parts · 10 questions Effect of Density on Populations (part 2 of 2) 8 ideas · 3 parts · 10 questions Community (part 1 of 2) 16 ideas · 4 parts · 10 questions Community (part 2 of 2) 14 ideas · 3 parts · 10 questions Biodiversity 15 ideas · 3 parts · 10 questions Disruptions in Ecosystems (part 1 of 3) 16 ideas · 5 parts · 10 questions Disruptions in Ecosystems (part 2 of 3) 16 ideas · 5 parts · 10 questions Disruptions in Ecosystems (part 3 of 3) 13 ideas · 3 parts · 10 questions Built from the College Board AP Biology Course and Exam Description V.1 (2025).