Interactive explorer
Tour an animal or plant cell: what each organelle does, the molecules inside it, related conditions and current research.
- Cell Biology
- Molecular Biology
- Biochemistry
An interactive atlas of the living world
Explore biology through interactive labs, simulations and a connected map of ideas, from DNA to ecosystems, with every claim linked to its source.
- linked concepts
- 143
- fields of biology
- 15
- interactive labs
- 8
- checked sources
- 276
The scale of life
Zoom out from a strand of DNA to the whole planet. Each level opens in the knowledge graph, where its links lead into every field.
Molecules
Instructions, messages and the machines they build.
DNA
2 nm wide
The molecule that stores the genetic instructions of all cellular life: two strands wound into a double helix and held together by base pairs.
Open in DNA & Genetics LabGene
Thousands of base pairs
A basic unit of heredity: a stretch of DNA with instructions for a product such as a protein or a functional RNA.
Open in DNA & Genetics LabRNA
Copies of genes
A single-stranded relative of DNA. Messenger RNA carries a gene's instructions to ribosomes, and other RNAs help build proteins and control genes.
Protein
A few nanometers
A chain of amino acids folded into a working shape. Proteins act as enzymes, structures, signals and transporters.
Cells and bodies
From a single cell to a whole living thing.
Cell
Micrometers
The smallest unit that can live on its own. Every living thing is made of one or more cells.
Open in Cell ExplorerTissue
Millimeters
A group of similar cells working together, such as muscle, nerve or leaf tissue.
Organ
Centimeters
Several tissues combined into a structure with a particular job, such as the heart, a kidney or a leaf.
Organism
Microbes to whales
An individual living thing, from a single bacterium to a tree or a person.
Living together
Groups of organisms, the places they share and the whole planet.
Population
One species
All the members of one species living in the same area at the same time.
Community
Many species
All the populations of different species living and interacting in one area.
Ecosystem
Life plus place
A community of living things together with its physical environment, linked by flows of energy and nutrients.
Open in Ecosystem SimulatorBiosphere
The whole planet
All of Earth's ecosystems together: every place on the planet where life exists.
Interactive labs
Explorers you can click through and simulations you can change. Every simulation is labeled as a simplified model.
Simulation
Pair bases, follow a real human gene from DNA to protein, make mutations, and predict inheritance with Punnett squares.
- Genetics
- Molecular Biology
- Biochemistry
Interactive explorer
Compare bacteria, archaea, fungi, protists and viruses side by side, and model how a bacterial culture grows.
- Microbiology
- Evolution
- Immunology
Interactive explorer
Follow water, sugar and gases through a plant, test what limits photosynthesis, and match hormones to their effects.
- Plant Biology
- Biochemistry
- Ecology
Timeline and explorer
A sourced timeline from the double helix to CRISPR therapies, eight technologies labeled established or emerging, and a PCR model.
- Biotechnology
- Synthetic Biology
- Genetics
Simulation
Change temperature, rainfall, soil and populations in a plant, herbivore and predator food chain, and watch the whole web respond.
- Ecology
- Plant Biology
- Evolution
Simulation
Watch natural selection and genetic drift change how common a gene version is, in small and large populations side by side.
- Evolution
- Genetics
- Ecology
Research Explorer
Search published papers and preprints, filter by field, study type and year, and open the original source.
Fields of biology
Fifteen ways of asking how life works. Each field page explains the field at three reading levels, with its big questions and key ideas.
How DNA, RNA and proteins store and use life's instructions.
The structures and machinery inside the basic unit of life.
How traits are inherited and how genes vary.
The chemistry of life: enzymes, energy and metabolism.
Bacteria, archaea, fungi, protists and viruses.
How the body recognizes and fights infection.
Neurons, signals and the brain.
How the human body is built and kept in balance.
How plants capture light, move water and grow.
How living things interact with each other and their environment.
How life changes over generations.
Life in the ocean, from the sunlit surface to deep-sea vents.
Using living systems to make medicines, tools and food.
Designing and building new biological systems.
Computing with biological data.
How Helicase works
Every claim is sourced
Facts link to the papers, textbooks and agency pages we checked them against. Emerging and debated findings are labeled as such.
Three reading levels
Choose beginner, intermediate or advanced explanations in Settings. Your choice is saved only in this browser.
Models are labeled
Simulations are simplified on purpose. Each one says so, and explains what it leaves out.
Evidence labels used across the site:EstablishedEmerging researchDebated
Sources & further reading
The explanations on this page are our own summaries of these sources. Follow a link to read the original; if anything here disagrees with it, the original wins. How we choose and check sources.
Deoxyribonucleic Acid (DNA) Fact Sheet (opens the original in a new tab)
National Human Genome Research Institute. genome.gov. National Human Genome Research Institute, NIH.
Fact sheetGovernment sourceWhat is DNA? (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducationalMolecular structure of nucleic acids; a structure for deoxyribose nucleic acid (opens the original in a new tab)
Watson JD, Crick FH (1953). Nature 171(4356):737-738.
Proposed the double-helix model of DNA.
Historical paperPrimary researchWhat is a gene? (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducationalMessenger RNA (mRNA) (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalHow do genes direct the production of proteins? (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducationalPotent and specific genetic interference by double-stranded RNA in Caenorhabditis elegans (opens the original in a new tab)
Fire A, Xu S, Montgomery MK, et al. (1998). Nature 391:806-811.
Discovery of RNA interference.
Peer-reviewedPrimary researchProtein (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalAmino Acids (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalPrinciples that govern the folding of protein chains (opens the original in a new tab)
Anfinsen CB (1973). Science 181:223-230.
Nobel lecture: a protein's sequence determines its folded structure.
Historical paperPrimary researchWhat is a cell? (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducationalCell (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalAnatomy and Physiology 2e (opens the original in a new tab)
OpenStax (2022). OpenStax, Rice University.
TextbookEducationalLicence: CC BY-NC-SA 4.0 (linked, not reused)
Biology 2e (opens the original in a new tab)
OpenStax (2018). OpenStax, Rice University.
Free introductory college textbook.
TextbookEducationalLicence: CC BY-NC-SA 4.0 (linked, not reused)
Primary production of the biosphere: integrating terrestrial and oceanic components (opens the original in a new tab)
Field CB, Behrenfeld MJ, Randerson JT, et al. (1998). Science 281:237-240.
Global net primary production of about 105 petagrams of carbon per year, split roughly evenly between land and ocean.
Peer-reviewedPrimary research