Biology for the AP® Course, Second Edition is the only major AP® Biology program built entirely for the AP® course. Unlike college texts adapted for high school, this text was written from the ground up to align with the latest 2025-2026 Course and Exam Description (CED), support the Big Ideas, and meet the needs of AP® students and teachers alike.

This trusted second edition adds even more AP® practice questions, new Unit-Opening Essays, a full Unit 0 on foundational skills, and end-of-unit Illustrative Examples that connect concepts to real-world science. The highly readable text balances accessibility with rigor—carefully scaffolding learning to help all students succeed with college-level biology.

Throughout the program, science practices are seamlessly integrated into the student friendly narrative along with visuals, activities, and assessments, helping students build the skills they need for the exam and beyond. Every element—from the AP® Exam Tips to the in-text tutorials and Practicing Science boxes—was crafted by a team of AP® experts, including former Chief Readers and longtime educators.

With powerful digital tools in Achieve—including assignable assessments, adaptive quizzing, and rich media like animations, simulations, and podcasts—this program equips teachers to deliver a complete, engaging, and effective AP® Biology experience.

Unit 0: Foundations

Module 01: Four Core Concepts of Biology

Module 02: Scientific Inquiry

Module 03: Visual Representations

Tutorial 1: Graphing

Illustrative Example: The Extinction of the Dinosaurs

Unit 1: Chemistry of Life

Module 1: Elements of Life

Module 2: Structure of Water and Hydrogen Bonding

Module 3: Carbohydrates and Lipids

Module 4: Nucleic Acids

Module 5: Proteins

Tutorial 2: Statistics

Illustrative Example: Luck and Penicillin

Unit 1 AP Practice Questions

Unit 2: Cells

Module 6: An Introduction to the Cell

Module 7: Cell Structure and Function

Module 8: Cell Size

Module 9: Plasma Membrane

Module 10: Mechanisms of Membrane Transport

Module 11: Osmosis, Tonicity, and Osmoregulation

Module 12: Origin of Compartmentalization and the Eukaryotic Cell

Illustrative Example: Plant–Fungal Associations

Unit 2 AP Practice Questions

Unit 3: Cellular Energetics

Module 13: Cellular Energy

Module 14: Enzymes and Environmental Impact on Enzyme Function

Module 15: Photosynthesis I: Overview

Module 16: Photosynthesis II: Biochemistry and Evolution

Module 17: Cellular Respiration I: Overview

Module 18: Cellular Respiration II: Biochemistry

Illustrative Example: A Photosynthetic Salamander

Unit 3 AP Practice Questions

Unit 4: Cell Communication and Cell Cycle

Module 19: Cell Communication

Module 20: Introduction to Signal Transduction

Module 21: Signal Transduction Pathways

Module 22: Feedback

Module 23: Cell Cycle

Module 24: Regulation of Cell Cycle

Illustrative Example: Cell Signaling and Cancer

Unit 4 AP Practice Questions

Unit 5: Heredity

Module 25: Meiosis and Genetic Diversity

Module 26: Mendelian Genetics

Tutorial 3: Probability

Module 27: Non-Mendelian Genetics

Module 28: Environmental Effects on Phenotypes

Illustrative Example: Living in a Lonely and Scary World

Unit 5 AP Practice Questions

Unit 6: Gene Expression and Regulation

Module 29: DNA and RNA Structure and Function

Module 30: DNA Replication

Module 31: Transcription and RNA Processing

Module 32: Translation

Module 33: Regulation of Gene Expression

Module 34: Cell Specialization and Development

Module 35: Mutations

Module 36: Biotechnology

Illustrative Example: CRISPR Scissors

Unit 6 AP Practice Questions

Unit 7: Evolution and Natural Selection

Module 37: Introduction to Evolution and Natural Selection

Module 38: Natural and Artificial Selection

Module 39: Population Genetics

Module 40: Hardy–Weinberg Equilibrium

Module 41: Evidence of Common Ancestry and Evolution

Module 42: Continuing Evolution

Module 43: Phylogeny

Module 44: Speciation

Module 45: Variation in Populations

Module 46: Origins of Life on Earth

Illustrative Example: The Anthropocene

Unit 7 AP Practice Questions

Unit 8: Ecology

Module 47: Responses to the Environment

Module 48: Energy Flow through Ecosystems

Module 49: Population Ecology

Module 50: Effect of Density on Populations

Tutorial 4: Rate and Growth in Populations Ecology

Module 51: Community Ecology

Module 52: Biodiversity

Module 53: Disruptions in Ecosystems

Illustrative Example: Impacts of Salt on Freshwater Ecosystems

Unit 8 AP Practice Questions

Cumulative AP Biology Practice Exam

Enrichment Modules

Enrichment Module A: The Nervous, Endocrine, and Immune Systems

Enrichment Module B: Animal Sensory Systems

Enrichment Module C: Viruses

Glossary / Glosario

Answers to Concept Check, Review, and Tutorial Practice Questions

The Periodic Table of the Elements