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Concepts of Biology

OpenStax · 105 sections in 22 chapters. Each section is its own page.

Front matter

• Preface

• Measurements and the Metric System

Introduction to Biology

• Introduction

• Themes and Concepts of Biology

• The Process of Science

Chemistry of Life

• Introduction

• The Building Blocks of Molecules

• Water

• Biological Molecules

Cell Structure and Function

• Introduction

• How Cells Are Studied

• Comparing Prokaryotic and Eukaryotic Cells

• Eukaryotic Cells

• The Cell Membrane

• Passive Transport

• Active Transport

How Cells Obtain Energy

• Introduction

• Energy and Metabolism

• Glycolysis

• Citric Acid Cycle and Oxidative Phosphorylation

• Fermentation

• Connections to Other Metabolic Pathways

Photosynthesis

• Introduction

• Overview of Photosynthesis

• The Light-Dependent Reactions of Photosynthesis

• The Calvin Cycle

Reproduction at the Cellular Level

• Introduction

• The Genome

• The Cell Cycle

• Cancer and the Cell Cycle

• Prokaryotic Cell Division

The Cellular Basis of Inheritance

• Introduction

• Sexual Reproduction

• Meiosis

• Variations in Meiosis

Patterns of Inheritance

• Introduction

• Mendel’s Experiments

• Laws of Inheritance

• Extensions of the Laws of Inheritance

Molecular Biology

• Introduction

• The Structure of DNA

• DNA Replication

• Transcription

• Translation

• How Genes Are Regulated

Biotechnology

• Introduction

• Cloning and Genetic Engineering

• Biotechnology in Medicine and Agriculture

• Genomics and Proteomics

Evolution and Its Processes

• Introduction

• Discovering How Populations Change

• Mechanisms of Evolution

• Evidence of Evolution

• Speciation

• Common Misconceptions about Evolution

Diversity of Life

• Introduction

• Organizing Life on Earth

• Determining Evolutionary Relationships

Diversity of Microbes, Fungi, and Protists

• Introduction

• Prokaryotic Diversity

• Eukaryotic Origins

• Protists

• Fungi

Diversity of Plants

• Introduction

• The Plant Kingdom

• Seedless Plants

• Seed Plants: Gymnosperms

• Seed Plants: Angiosperms

Diversity of Animals

• Introduction

• Features of the Animal Kingdom

• Sponges and Cnidarians

• Flatworms, Nematodes, and Arthropods

• Mollusks and Annelids

• Echinoderms and Chordates

• Vertebrates

The Body’s Systems

• Introduction

• Homeostasis and Osmoregulation

• Digestive System

• Circulatory and Respiratory Systems

• Endocrine System

• Musculoskeletal System

• Nervous System

The Immune System and Disease

• Introduction

• Viruses

• Innate Immunity

• Adaptive Immunity

• Disruptions in the Immune System

Animal Reproduction and Development

• Introduction

• How Animals Reproduce

• Development and Organogenesis

• Human Reproduction

Population and Community Ecology

• Introduction

• Population Demographics and Dynamics

• Population Growth and Regulation

• The Human Population

• Community Ecology

Ecosystems and the Biosphere

• Introduction

• Energy Flow through Ecosystems

• Biogeochemical Cycles

• Terrestrial Biomes

• Aquatic and Marine Biomes

Conservation and Biodiversity

• Introduction

• Importance of Biodiversity

• Threats to Biodiversity

• Preserving Biodiversity

Attribution. Concepts of Biology, OpenStax, Rice University, and the contributing authors credited in the book. Licensed under Creative Commons Attribution 4.0 International. Source revision d2779c2edf of openstax/osbooks-biology-bundle (2026-02-03). CC BY 4.0. Original source ↗. Text edition of a pinned CC BY 4.0 source revision of the OpenStax book, converted from CNXML by the EvidenceHelix importer. Original prose, learning objectives, tables, exercises, glossary and captions are preserved; images are not copied (figures link to the original source and keep their credits). No new content was added. Later revisions of this book can carry different licence terms and are not used.