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
Labs
Explorers, simulations and a literature search. Each lab explains what it shows at your reading level and links every fact to its source.
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
Literature search
Search published papers and preprints, filter by field, study type and year, and open the original source.
- Bioinformatics
- Molecular Biology
- Ecology
About the simulations
The simulations are simplified models. They show how a system tends to behave, not what will happen in a real culture, plant or ecosystem. Each one is labeled on its page and explains its assumptions.
Biosafety
The labs teach concepts. They do not give instructions for growing organisms or for handling hazardous materials.
Sources & further reading
The topics these labs cover, and the sources behind them. Each lab page lists its own sources in full. How we choose and check sources.
What 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 sourceEducationalNucleus (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 sourceEducationalMolecular Biology of the Cell (4th edition) (opens the original in a new tab)
Alberts B, Johnson A, Lewis J, et al. (2002). Garland Science.
Free to read on NCBI Bookshelf. Standard reference for cell structure and molecular biology.
TextbookEducationalThe Cell: A Molecular Approach (2nd edition) (opens the original in a new tab)
Cooper GM (2000). Sinauer Associates.
Free to read on NCBI Bookshelf.
TextbookEducationalMitochondria (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 sourceEducationalCoupling of phosphorylation to electron and hydrogen transfer by a chemi-osmotic type of mechanism (opens the original in a new tab)
Mitchell P (1961). Nature 191:144-148.
The chemiosmotic hypothesis for how cells make ATP.
Historical paperTheory or modelThe ATP synthase: a splendid molecular machine (opens the original in a new tab)
Boyer PD (1997). Annual Review of Biochemistry 66:717-749.
Editorially reviewedReviewRibosome (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 sourceEducationalThe structural basis of ribosome activity in peptide bond synthesis (opens the original in a new tab)
Nissen P, Hansen J, Ban N, et al. (2000). Science 289:920-930.
Structural evidence that ribosomal RNA, not protein, catalyzes peptide bond formation.
Peer-reviewedPrimary researchThe complete atomic structure of the large ribosomal subunit at 2.4 Å resolution (opens the original in a new tab)
Ban N, Nissen P, Hansen J, et al. (2000). Science 289:905-920.
Peer-reviewedPrimary researchIntracellular aspects of the process of protein synthesis (opens the original in a new tab)
Palade G (1975). Science 189:347-358.
Nobel lecture on the secretory pathway through the ER and Golgi.
Peer-reviewedReview
Show 85 more sourcesHide 85 sources
Golgi Body (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 sourceEducationalLysosome (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 sourceEducationalExploring cells with a centrifuge (opens the original in a new tab)
de Duve C (1975). Science 189:186-194.
Nobel lecture describing the discovery of lysosomes.
Peer-reviewedReviewLysosomes as dynamic regulators of cell and organismal homeostasis (opens the original in a new tab)
Ballabio A, Bonifacino JS (2020). Nature Reviews Molecular Cell Biology 21:101-118.
Peer-reviewedReviewCell Membrane (Plasma Membrane) (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 sourceEducationalSingle-channel currents recorded from membrane of denervated frog muscle fibres (opens the original in a new tab)
Neher E, Sakmann B (1976). Nature 260:799-802.
Peer-reviewedPrimary researchCell mechanics and the cytoskeleton (opens the original in a new tab)
Fletcher DA, Mullins RD (2010). Nature 463:485-492.
Peer-reviewedReviewPrimary ciliary dyskinesia (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducationalBiology 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)
Endosymbiosis and eukaryotic cell evolution (opens the original in a new tab)
Archibald JM (2015). Current Biology 25:R911-R921.
Peer-reviewedReviewThe global mass and average rate of rubisco (opens the original in a new tab)
Bar-On YM, Milo R (2019). Proceedings of the National Academy of Sciences 116:4738-4743.
Estimates about 0.7 gigatonnes of rubisco on Earth, mostly in land plant leaves.
Peer-reviewedPrimary researchDeoxyribonucleic 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 researchBase Pair (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 sourceEducationalTranscription (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 sourceEducationalTranslation (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 sourceEducationalCodon (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 sourceEducationalThe dependence of cell-free protein synthesis in E. coli upon naturally occurring or synthetic polyribonucleotides (opens the original in a new tab)
Nirenberg MW, Matthaei JH (1961). Proceedings of the National Academy of Sciences 47:1588-1602.
First codon assignment: poly-U RNA directs synthesis of polyphenylalanine.
Historical paperPrimary researchGeneral nature of the genetic code for proteins (opens the original in a new tab)
Crick FH, Barnett L, Brenner S, et al. (1961). Nature 192:1227-1232.
Frameshift experiments indicating the code is read in non-overlapping triplets.
Historical paperPrimary researchMutation (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 sourceEducationalWhat kinds of gene variants are possible? (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducationalSickle cell disease (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducationalGene mutations in human haemoglobin: the chemical difference between normal and sickle cell haemoglobin (opens the original in a new tab)
Ingram VM (1957). Nature 180:326-328.
Traced sickle cell hemoglobin to a single amino acid change.
Historical paperPrimary researchSickle cell anemia, a molecular disease (opens the original in a new tab)
Pauling L, Itano HA, Singer SJ, et al. (1949). Science 110:543-548.
Historical paperPrimary researchExperiments on Plant Hybrids by Gregor Mendel (opens the original in a new tab)
Abbott S, Fairbanks DJ (2016). Genetics 204:407-422.
A modern English translation of Mendel's 1866 paper.
Peer-reviewedTranslationBacteria (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 sourceEducationalMicrobiology (opens the original in a new tab)
OpenStax (2016). OpenStax, Rice University.
TextbookEducationalLicence: CC BY-NC-SA 4.0 (linked, not reused)
Phylogenetic structure of the prokaryotic domain: the primary kingdoms (opens the original in a new tab)
Woese CR, Fox GE (1977). Proceedings of the National Academy of Sciences 74:5088-5090.
Ribosomal RNA comparisons revealed the archaea as a separate lineage.
Peer-reviewedPrimary researchTowards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya (opens the original in a new tab)
Woese CR, Kandler O, Wheelis ML (1990). Proceedings of the National Academy of Sciences 87:4576-4579.
Peer-reviewedPerspectiveVirus (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 sourceEducationalExpression of animal virus genomes (opens the original in a new tab)
Baltimore D (1971). Bacteriological Reviews 35:235-241.
Classified viruses by how their genomes produce mRNA.
Historical paperReviewThe growth of bacterial cultures (opens the original in a new tab)
Monod J (1949). Annual Review of Microbiology 3:371-394.
Described bacterial growth phases and the saturating dependence of growth rate on nutrient concentration.
Historical paperReviewThermus aquaticus gen. n. and sp. n., a nonsporulating extreme thermophile (opens the original in a new tab)
Brock TD, Freeze H (1969). Journal of Bacteriology 98:289-297.
Isolation of the hot-spring bacterium later used as the source of Taq polymerase.
Historical paperPrimary researchDeoxyribonucleic acid polymerase from the extreme thermophile Thermus aquaticus (opens the original in a new tab)
Chien A, Edgar DB, Trela JM (1976). Journal of Bacteriology 127:1550-1557.
Peer-reviewedPrimary researchPrimer-directed enzymatic amplification of DNA with a thermostable DNA polymerase (opens the original in a new tab)
Saiki RK, Gelfand DH, Stoffel S, et al. (1988). Science 239:487-491.
PCR with heat-stable Taq polymerase.
Peer-reviewedPrimary researchThe rules of engagement in the legume-rhizobial symbiosis (opens the original in a new tab)
Oldroyd GE, Murray JD, Poole PS, et al. (2011). Annual Review of Genetics 45:119-144.
Editorially reviewedReviewProchlorococcus, a marine photosynthetic prokaryote of global significance (opens the original in a new tab)
Partensky F, Hess WR, Vaulot D (1999). Microbiology and Molecular Biology Reviews 63:106-127.
Peer-reviewedReviewPresent and future global distributions of the marine Cyanobacteria Prochlorococcus and Synechococcus (opens the original in a new tab)
Flombaum P, Gallegos JL, Gordillo RA, et al. (2013). Proceedings of the National Academy of Sciences 110:9824-9829.
Peer-reviewedPrimary researchThe path of carbon in photosynthesis (opens the original in a new tab)
Bassham JA, Benson AA, Calvin M (1950). Journal of Biological Chemistry 185:781-787.
Historical paperPrimary researchThe cohesion-tension theory of sap ascent: current controversies (opens the original in a new tab)
Tyree MT (1997). Journal of Experimental Botany 48:1753-1765.
Peer-reviewedReviewTesting the Münch hypothesis of long distance phloem transport in plants (opens the original in a new tab)
Knoblauch M, Knoblauch J, Mullendore DL, et al. (2016). eLife 5:e15341.
Peer-reviewedPrimary researchThe role of stomata in sensing and driving environmental change (opens the original in a new tab)
Hetherington AM, Woodward FI (2003). Nature 424:901-908.
Peer-reviewedReviewRecent advances and emerging trends in plant hormone signalling (opens the original in a new tab)
Santner A, Estelle M (2009). Nature 459:1071-1078.
Peer-reviewedReviewWhat is Pollination? (opens the original in a new tab)
USDA Forest Service. fs.usda.gov. U.S. Department of Agriculture, Forest Service.
ReferenceGovernment sourceEducationalRecombinant DNA Technology (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 sourceEducationalConstruction of biologically functional bacterial plasmids in vitro (opens the original in a new tab)
Cohen SN, Chang AC, Boyer HW, et al. (1973). Proceedings of the National Academy of Sciences 70:3240-3244.
Recombinant plasmids that replicate in bacteria.
Historical paperPrimary researchHuman insulin from recombinant DNA technology (opens the original in a new tab)
Johnson IS (1983). Science 219:632-637.
Peer-reviewedReviewPolymerase Chain Reaction (PCR) (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 sourceEducationalDNA sequencing with chain-terminating inhibitors (opens the original in a new tab)
Sanger F, Nicklen S, Coulson AR (1977). Proceedings of the National Academy of Sciences 74:5463-5467.
Peer-reviewedPrimary researchThe complete sequence of a human genome (opens the original in a new tab)
Nurk S, Koren S, Rhie A, et al. (2022). Science 376:44-53.
The Telomere-to-Telomere consortium's gapless human genome assembly.
Peer-reviewedPrimary researchCRISPR (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 sourceEducationalCRISPR provides acquired resistance against viruses in prokaryotes (opens the original in a new tab)
Barrangou R, Fremaux C, Deveau H, et al. (2007). Science 315:1709-1712.
Peer-reviewedPrimary researchA programmable dual-RNA-guided DNA endonuclease in adaptive bacterial immunity (opens the original in a new tab)
Jinek M, Chylinski K, Fonfara I, et al. (2012). Science 337:816-821.
Showed Cas9 can be programmed with guide RNA to cut chosen DNA sequences.
Peer-reviewedPrimary researchMultiplex genome engineering using CRISPR/Cas systems (opens the original in a new tab)
Cong L, Ran FA, Cox D, et al. (2013). Science 339:819-823.
Peer-reviewedPrimary researchProgrammable editing of a target base in genomic DNA without double-stranded DNA cleavage (opens the original in a new tab)
Komor AC, Kim YB, Packer MS, et al. (2016). Nature 533:420-424.
Peer-reviewedPrimary researchSearch-and-replace genome editing without double-strand breaks or donor DNA (opens the original in a new tab)
Anzalone AV, Randolph PB, Davis JR, et al. (2019). Nature 576:149-157.
Peer-reviewedPrimary researchWhat is Gene Therapy? (opens the original in a new tab)
U.S. Food and Drug Administration. fda.gov. U.S. Food and Drug Administration.
ReferenceGovernment sourceEducationalGene Therapy (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 sourceEducationalFDA Approves First Gene Therapies to Treat Patients with Sickle Cell Disease (opens the original in a new tab)
U.S. Food and Drug Administration (2023). FDA News Release. U.S. Food and Drug Administration. Published 2023-12-08.
Approval of Casgevy (CRISPR-based) and Lyfgenia for patients 12 and older.
Regulatory noticeGovernment sourceSuppression of RNA recognition by Toll-like receptors: the impact of nucleoside modification and the evolutionary origin of RNA (opens the original in a new tab)
Karikó K, Buckstein M, Ni H, et al. (2005). Immunity 23:165-175.
Modified nucleosides reduce innate immune recognition of synthetic mRNA.
Peer-reviewedPrimary researchSafety and efficacy of the BNT162b2 mRNA Covid-19 vaccine (opens the original in a new tab)
Polack FP, Thomas SJ, Kitchin N, et al. (2020). New England Journal of Medicine 383:2603-2615.
Peer-reviewedClinical trialEfficacy and safety of the mRNA-1273 SARS-CoV-2 vaccine (opens the original in a new tab)
Baden LR, El Sahly HM, Essink B, et al. (2021). New England Journal of Medicine 384:403-416.
Peer-reviewedClinical trialA brief history of synthetic biology (opens the original in a new tab)
Cameron DE, Bashor CJ, Collins JJ (2014). Nature Reviews Microbiology 12:381-390.
Peer-reviewedReviewLaboratory biosafety manual, 4th edition (opens the original in a new tab)
World Health Organization (2020). WHO publications. World Health Organization. Published 2020-12-21.
GuidanceIntergovernmental sourceBiosafety in Microbiological and Biomedical Laboratories (BMBL), 6th Edition (opens the original in a new tab)
Centers for Disease Control and Prevention, National Institutes of Health. CDC Laboratories. U.S. Department of Health and Human Services.
The U.S. reference for laboratory biosafety practice.
GuidanceGovernment sourceSummary statement of the Asilomar conference on recombinant DNA molecules (opens the original in a new tab)
Berg P, Baltimore D, Brenner S, et al. (1975). Proceedings of the National Academy of Sciences 72:1981-1984.
Scientists' own guidelines for the safe conduct of recombinant DNA research.
Peer-reviewedPerspectiveFood web complexity and species diversity (opens the original in a new tab)
Paine RT (1966). The American Naturalist 100:65-75.
Removing a predatory sea star from rocky shores reduced the number of species present.
Historical paperPrimary researchSea otters: their role in structuring nearshore communities (opens the original in a new tab)
Estes JA, Palmisano JF (1974). Science 185:1058-1060.
Historical paperPrimary researchTrophic cascades in Yellowstone: the first 15 years after wolf reintroduction (opens the original in a new tab)
Ripple WJ, Beschta RL (2012). Biological Conservation 145:205-213.
Peer-reviewedReviewDoes restoring apex predators to food webs restore ecosystems? Large carnivores in Yellowstone as a model system (opens the original in a new tab)
Hobbs NT, Johnston DB, Marshall KN, et al. (2024). Ecological Monographs 94.
Field experiments questioning how fully wolf reintroduction restored Yellowstone's streamside vegetation.
Peer-reviewedPrimary researchA note on trophic complexity and community stability (opens the original in a new tab)
Paine RT (1969). The American Naturalist 103:91-93.
Introduced the term keystone species.
Historical paperPerspectiveFluctuations in the abundance of a species considered mathematically (opens the original in a new tab)
Volterra V (1926). Nature 118:558-560.
One of the founding mathematical models of predator-prey cycles.
Historical paperTheory or modelWhat drives the 10-year cycle of snowshoe hares? (opens the original in a new tab)
Krebs CJ, Boonstra R, Boutin S, et al. (2001). BioScience 51:25-35.
Real population cycles involve food, predators and more; simple two-species models leave much out.
Peer-reviewedReviewSome characteristics of simple types of predation and parasitism (opens the original in a new tab)
Holling CS (1959). The Canadian Entomologist 91:385-398.
Introduced the functional response: how a predator's feeding rate saturates as prey become abundant.
Historical paperPrimary researchParadox of enrichment: destabilization of exploitation ecosystems in ecological time (opens the original in a new tab)
Rosenzweig ML (1971). Science 171:385-387.
In some models, adding resources makes predator-prey cycles larger and less stable.
Historical paperTheory or modelEvolution (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 sourceEducationalEvolution of character displacement in Darwin's finches (opens the original in a new tab)
Grant PR, Grant BR (2006). Science 313:224-226.
Peer-reviewedPrimary researchSelective bird predation on the peppered moth: the last experiment of Michael Majerus (opens the original in a new tab)
Cook LM, Grant BS, Saccheri IJ, et al. (2012). Biology Letters 8:609-612.
Peer-reviewedPrimary researchEvolution in Mendelian populations (opens the original in a new tab)
Wright S (1931). Genetics 16:97-159.
Historical paperTheory or modelOn the probability of fixation of mutant genes in a population (opens the original in a new tab)
Kimura M (1962). Genetics 47:713-719.
Historical paperTheory or modelAllele (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 sourceEducationalGenBank Overview (opens the original in a new tab)
National Center for Biotechnology Information. ncbi.nlm.nih.gov. National Library of Medicine, NIH.
DatabaseGovernment sourceUniProt: the Universal Protein Knowledgebase in 2023 (opens the original in a new tab)
UniProt Consortium (2023). Nucleic Acids Research 51:D523-D531.
Peer-reviewedPrimary researchThe Protein Data Bank (opens the original in a new tab)
Berman HM, Westbrook J, Feng Z, et al. (2000). Nucleic Acids Research 28:235-242.
Peer-reviewedPrimary research