AP map · Biology Ladder
AP Biology
A year of college introductory biology: the chemistry of life, cells, cellular energetics, cell communication and the cell cycle, heredity, gene expression, natural selection and ecology, with data analysis throughout.
Unit names: AP Biology course page and Course and Exam Description (College Board, updated for 2025–26), unit list, read October 25, 2026.
Unit 1 Chemistry of Life
8–11% of multiple choice- The Elements and Bonds of Life
- The Properties of Water
- Acids, Bases and pH
- Monomers and Polymers
- Carbohydrates
- Lipids
- Proteins
- Nucleic Acids
- Levels of Protein Structure
- Amino Acid R Groups
- The Direction of DNA and RNA
Water and hydrogen bonding, the elements of life, and the structure and function of the four kinds of biological macromolecules, including nucleic acid direction and protein structure levels.
8 mixed questions, with the steps after eachUnit 2 Cells
10–13% of multiple choice- Prokaryotic and Eukaryotic Cells
- The Endomembrane System
- Where Mitochondria and Chloroplasts Came From
- Surface Area to Volume
- The Cell Membrane
- Diffusion and Concentration Gradients
- Osmosis and Tonicity
- Channels, Carriers and Pumps
- Endocytosis and Exocytosis
- Water Potential
- Membrane Potential
- Compartmentalization
Cell structures, cell size, membranes and transport, tonicity and water potential, and compartmentalization with its endosymbiotic origin.
8 mixed questions, with the steps after eachUnit 3 Cellular Energetics
12–16% of multiple choice- Enzymes
- Temperature, pH and Enzymes
- Enzyme Kinetics
- Competitive and Noncompetitive Inhibition
- ATP: The Cell's Energy Currency
- Free Energy and Coupled Reactions
- Photosynthesis
- The Light Reactions
- The Calvin Cycle
- What Limits Photosynthesis
- C4 and CAM Plants
- Cellular Respiration
- Glycolysis and the Krebs Cycle
- Oxidative Phosphorylation
- Fermentation
Enzyme structure and kinetics, energy coupling, and photosynthesis and cellular respiration step by step. C4 and CAM plants are taught as an extension.
8 mixed questions, with the steps after eachUnit 4 Cell Communication and Cell Cycle
10–15% of multiple choice- How Cells Signal
- Reception, Transduction and Response
- Amplification and Changes in Pathways
- Homeostasis and Feedback
- Feedback in Living Systems
- The Cell Cycle
- Mitosis
- Controlling the Cell Cycle
- Regulating the Cell Cycle
Signaling, reception, transduction and responses, changes in pathways, feedback, and the cell cycle and its regulation.
8 mixed questions, with the steps after eachUnit 5 Heredity
8–11% of multiple choice- Chromosomes and Their Numbers
- Meiosis
- How Meiosis Makes Variation
- Mitosis and Meiosis Compared
- Mendel's Experiments
- Monohybrid Crosses
- Probability Rules for Genetics
- Dihybrid Crosses
- Chi-Square Goodness of Fit
- Incomplete Dominance and Codominance
- Multiple Alleles: Blood Types
- X-Linked Traits
- Reading Pedigrees
- Linked Genes
- Recombination Frequency and Gene Maps
- Inheritance Outside the Nucleus
- Nondisjunction
- Environment and Phenotype
- Polygenic Traits and the Environment
Meiosis and genetic diversity, Mendelian genetics with probability and chi-square, non-Mendelian inheritance (linkage, X-linked traits, organelle genes), environmental effects on phenotype, and nondisjunction as an error of cell division. Human chromosomal disorders are not covered.
8 mixed questions, with the steps after eachUnit 6 Gene Expression and Regulation
12–16% of multiple choice- The Structure of DNA
- DNA Replication
- Replication in Detail
- Transcription
- Transcription and RNA Processing
- Translation
- Reading the Genetic Code
- Translation in Detail
- Turning Genes On and Off
- Operons: lac and trp
- Gene Regulation in Eukaryotes
- Gene Expression and Specialization
- Mutations
- Mutations and Their Effects
- PCR: Copying DNA
- Gel Electrophoresis
- Sizing DNA on a Gel
- Recombinant DNA
- Transformation and DNA Sequencing
DNA and RNA structure, replication, transcription and RNA processing, translation, regulation and cell specialization, mutations, and biotechnology (PCR, gels, transformation and sequencing). Hands-on lab work is part of the AP course and no website replaces it.
8 mixed questions, with the steps after eachUnit 7 Natural Selection
13–20% of multiple choice- Natural Selection
- Directional, Stabilizing and Disruptive Selection
- Evolution in Action
- Selective Breeding and Genetic Engineering
- Hardy-Weinberg Equilibrium
- Hardy-Weinberg Problems
- Mutation, Drift, Gene Flow and Selection
- Genetic Drift
- Evidence: Fossils and Anatomy
- Evidence: DNA and Proteins
- Molecular Clocks
- Reading Phylogenetic Trees
- Building Cladograms
- Building Trees from Data
- How New Species Form
- Patterns of Speciation and Extinction
- Early Earth and the Origin of Life
Natural and artificial selection, population genetics and Hardy-Weinberg, evidence of common ancestry, phylogeny, speciation and extinction, variation in populations, and the origin of life (taught as evidence and open questions). Speciation is taught through gene flow, geography, habitat and timing; behavioral and mechanical isolating barriers are not covered.
8 mixed questions, with the steps after eachUnit 8 Ecology
10–15% of multiple choice- Responses to the Environment
- Group Behavior
- Energy Flow and Biomass
- Energy Budgets and Metabolism
- Primary Productivity
- Exponential and Logistic Growth
- Population Growth Equations
- Density-Dependent and Independent Factors
- Niches and Community Interactions
- Keystone Species and Trophic Cascades
- Community Structure and Trophic Cascades
- Biodiversity and Human Impact
- Measuring Diversity
- Stability, Disturbance and Change
- Disruptions to Ecosystems
- The Carbon, Nitrogen and Phosphorus Cycles
Responses to the environment, energy flow, population ecology, community ecology, biodiversity and disruptions to ecosystems. Animal behavior is limited to responses, communication and group behavior.
8 mixed questions, with the steps after each