College Admissions AP Prep SAT PrepNew Pricing Contact us

Log in Get started

AP®︎ Biology Study Guides

Prepare for your quiz, test, or the AP exam with comprehensive study guides that cover everything you need to know. Select a unit or topic to begin.

Unit 1: Chemistry of Life

All Topics
Complete Unit Review

Topic 1.1
Structure of Water and Hydrogen Bonding

Topic 1.2
Elements of Life

Topic 1.3
Introduction to Macromolecules

Topic 1.4
Carbohydrates

Topic 1.5
Lipids

Topic 1.6
Nucleic Acids

Topic 1.7
Proteins

Unit 2: Cell Structure and Function

All Topics
Complete Unit Review

Topic 2.1
Cell Structure and Function

Topic 2.2
Cell Size

Topic 2.3
Plasma Membrane

Topic 2.4
Membrane Permeability

Topic 2.5
Membrane Transport

Topic 2.6
Facilitated Diffusion

Topic 2.7
Tonicity and Osmoregulation

Topic 2.8
Mechanisms of Transport

Topic 2.9
Cell Compartmentalization

Topic 2.10
Origins of Cell Compartmentalization

Unit 3: Cellular Energetics

All Topics
Complete Unit Review

Topic 3.1
Enzymes

Topic 3.2
Environmental Impacts on Enzyme Function

Topic 3.3
Cellular Energy

Topic 3.4
Photosynthesis

Topic 3.5
Cellular Respiration

Unit 4: Cell Communication and Cell Cycle

All Topics
Complete Unit Review

Topic 4.1
Cell Communication

Topic 4.2
Introduction to Signal Transduction

Topic 4.3
Signal Transduction Pathways

Topic 4.4
Feedback

Topic 4.5
Cell Cycle

Topic 4.6
Regulation of Cell Cycle

Unit 5: Heredity

All Topics
Complete Unit Review

Topic 5.1
Meiosis

Topic 5.2
Meiosis and Genetic Diversity

Topic 5.3
Mendelian Genetics

Topic 5.4
Non-Mendelian Genetics

Topic 5.5
Environmental Effects on Phenotype

Unit 6: Gene Expression and Regulation

All Topics
Complete Unit Review

Topic 6.1
DNA and RNA Structure

Topic 6.2
DNA Replication

Topic 6.3
Transcription and RNA Processing

Topic 6.4
Translation

Topic 6.5
Regulation of Gene Expression

Topic 6.6
Gene Expression and Cell Specialization

Topic 6.7
Mutations

Topic 6.8
Biotechnology

Unit 7: Natural Selection

All Topics
Complete Unit Review

Topic 7.1
Introduction to Natural Selection

Topic 7.2
Natural Selection

Topic 7.3
Artificial Selection

Topic 7.4
Population Genetics

Topic 7.5
Hardy–Weinberg Equilibrium

Topic 7.6
Evidence of Evolution

Topic 7.7
Common Ancestry

Topic 7.8
Continuing Evolution

Topic 7.9
Phylogeny

Topic 7.10
Speciation

Topic 7.11
Variations in Populations

Topic 7.12
Origins of Life on Earth

Unit 8: Ecology

All Topics
Complete Unit Review

Topic 8.1
Responses to the Environment

Topic 8.2
Energy Flow Through Ecosystems

Topic 8.3
Population Ecology

Topic 8.4
Effect of Density on Populations

Topic 8.5
Community Ecology

Topic 8.6
Biodiversity

Topic 8.7
Disruptions in Ecosystems

Also applying to college?Free college essay reviewGet your college essay graded