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APIntermediate
AP Biology
From cell structure to genetics, master the full AP Biology sequence with an AI layer that remembers how you learn.
📚 8 units🤖 AI-guided support✅ Practice questions included
📖Open Textbook→Course Units
2025–26 College Board CED1
Chemistry of Life8–11% of exam
1.1
Why Water Makes Life Possible
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1.2
Carbon: The Backbone of Life
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1.3
Carbohydrates — Energy and Structure
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1.4
Lipids — Membranes, Energy, Signals
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1.5
Proteins — Structure Dictates Function
Coming Soon
1.6
Nucleic Acids — Storing and Transmitting Information
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1.7
Enzymes: Lowering the Activation Energy Barrier
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1.8
Cell Membrane Structure and Transport
Coming Soon
2
Cell Structure and Function10–13% of exam
2.1
Prokaryotes vs. Eukaryotes — What the Difference Actually Means
Coming Soon
2.2
Organelles: Form Follows Function
Coming Soon
2.3
The Cytoskeleton — More Than a Scaffold
Coming Soon
2.4
Cell Signaling — Receptors and Second Messengers
Coming Soon
2.5
Membrane Transport — Moving Molecules In and Out
Coming Soon
2.6
Water Potential and Osmosis in Plant vs. Animal Cells
Coming Soon
2.7
Cell Communication: Direct Contact, Local, and Long-Distance
Coming Soon
2.8
Feedback Loops and Homeostasis
Coming Soon
3
Cellular Energetics12–16% of exam
3.1
Energy, Entropy, and Why Reactions Happen
Coming Soon
3.2
ATP: The Currency of Cellular Work
Coming Soon
3.3
Glycolysis — The Universal Starting Point
Coming Soon
3.4
Pyruvate Oxidation and the Citric Acid Cycle
Coming Soon
3.5
Electron Transport Chain and ATP Synthesis
Coming Soon
3.6
Fermentation — Surviving Without Oxygen
Coming Soon
3.7
Photosynthesis Overview — Light Reactions
Coming Soon
3.8
Calvin Cycle — Fixing Carbon into Sugar
Coming Soon
3.9
Cellular Respiration vs. Photosynthesis: The Energy Accounting
Coming Soon
4
Cell Communication and Cell Cycle10–15% of exam
4.1
Signal Transduction: From Reception to Response
Coming Soon
4.2
Cell Cycle: Phases, Checkpoints, and Control
Coming Soon
4.3
Mitosis — Precise Chromosome Segregation
Coming Soon
4.4
Meiosis — Generating Genetic Diversity
Coming Soon
4.5
Cancer: When Cell Cycle Control Fails
Coming Soon
4.6
Apoptosis — Programmed Cell Death as a Survival Strategy
Coming Soon
4.7
Stem Cells and Cell Differentiation
Coming Soon
4.8
Extracellular Matrix and Cell Junctions
Coming Soon
5
Heredity8–11% of exam
5.1
Mendelian Genetics — The Rules of Inheritance
Coming Soon
5.2
Beyond Mendelian Genetics — Dominance Patterns
Coming Soon
5.3
Linked Genes and Recombination
Coming Soon
5.4
Sex Determination and X-Linked Inheritance
Coming Soon
5.5
Pedigree Analysis — Diagnosing Inheritance Patterns
Coming Soon
5.6
Chromosomal Mutations — Nondisjunction and Aneuploidy
Coming Soon
5.7
Epigenetics — Inheritance Without DNA Change
Coming Soon
5.8
Quantitative Genetics — Polygenic Traits and Environment
Coming Soon
6
Gene Expression and Regulation12–16% of exam
6.1
DNA Replication — Accuracy and the Machinery
Coming Soon
6.2
Transcription — Reading DNA into RNA
Coming Soon
6.3
Translation — Decoding mRNA into Protein
Coming Soon
6.4
Mutations — Types, Consequences, and Repair
Coming Soon
6.5
Gene Regulation in Prokaryotes — The Operon Model
Coming Soon
6.6
Gene Regulation in Eukaryotes — Chromatin to Translation
Coming Soon
6.7
Biotechnology — PCR, Gel Electrophoresis, Cloning
Coming Soon
6.8
Gene Editing and CRISPR — Mechanism and Applications
Coming Soon
7
Natural Selection13–20% of exam
7.1
Darwin's Mechanisms — Variation, Heritability, Selection
Coming Soon
7.2
Hardy-Weinberg Equilibrium — The Null Model
Coming Soon
7.3
Types of Natural Selection — Directional, Stabilizing, Disruptive
Coming Soon
7.4
Genetic Drift and Gene Flow
Coming Soon
7.5
Sexual Selection and Non-Random Mating
Coming Soon
7.6
Speciation — How New Species Form
Coming Soon
7.7
Phylogenetics — Reading the Tree of Life
Coming Soon
7.8
Evidence for Evolution — Fossils, Biogeography, Molecular
Coming Soon
8
Ecology10–15% of exam
8.1
Population Ecology — Growth Models and Limiting Factors
Coming Soon
8.2
Community Ecology — Interactions and Stability
Coming Soon
8.3
Ecosystem Ecology — Energy Flow and Trophic Levels
Coming Soon
8.4
Biogeochemical Cycles — Carbon, Nitrogen, Phosphorus
Coming Soon
8.5
Ecological Succession — Primary and Secondary
Coming Soon
8.6
Biodiversity and Conservation
Coming Soon
8.7
Human Impacts — Climate, Invasives, Extinction
Coming Soon
8.8
Behavior — Proximate and Ultimate Causes
Coming Soon