Level of life
Cell
The smallest unit that can live on its own. Every living thing is made of one or more cells.
Cell Biology
The structures and machinery inside the basic unit of life.
Cell biology studies cells, the tiny units every living thing is made of, and the parts inside them.
Cell biologists study organelles, membranes and the cytoskeleton, and how cells grow, divide, communicate and die.
The field spans organelle function, protein trafficking, cell mechanics and signaling, and the origin of complex cells through endosymbiosis.
Big questions
- How do the parts of a cell work together?
- How do proteins reach the right place in a cell?
- Where did cells with a nucleus come from?
Key ideas
Open any idea in the knowledge graph to see what it connects to, here and in other fields.
Structure
Nucleus
Stores most of the cell's DNA and controls which genes are used.
Structure
Mitochondria
Convert energy from food into ATP, the cell's usable energy.
Structure
Ribosomes
Build proteins by reading messenger RNA.
Structure
Endoplasmic reticulum
Makes and folds proteins and lipids for membranes and export.
Structure
Golgi apparatus
Modifies, sorts and ships proteins and lipids.
Structure
Lysosomes
Break down and recycle worn-out parts and waste.
Structure
Cell membrane
Controls what enters and leaves the cell.
Structure
Cytoskeleton
Gives the cell its shape and moves things inside it.
Structure
Chloroplasts
Capture light energy to make sugar by photosynthesis.
Idea or model
Endosymbiosis
Mitochondria and chloroplasts descend from bacteria that came to live inside other cells long ago.
Structure
Stem cells
Cells that can renew themselves and give rise to specialized cells. Adult cells can be reprogrammed into stem-cell-like iPS cells.
Idea or model
Cells of the human body
An adult has roughly 30 to 37 trillion human cells, and about 90 percent of them belong to the blood-forming lineage.
Also in Cell Biology
Explore it in the labs
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
Interactive explorer
Compare bacteria, archaea, fungi, protists and viruses side by side, and model how a bacterial culture grows.
- Microbiology
- Evolution
- Immunology
Current research
Search published papers and preprints in Cell Biology, with clear labels for reviews, primary research, clinical trials and preprints.
Search papers in Cell BiologySources & 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.
Molecular 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.
TextbookEducationalEndosymbiosis and eukaryotic cell evolution (opens the original in a new tab)
Archibald JM (2015). Current Biology 25:R911-R921.
Peer-reviewedReviewWhat 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 sourceEducationalMitochondria (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 research
Show 15 more sourcesHide 15 sources
Intracellular 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-reviewedReviewGolgi 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)
The 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 researchOn the origin of mitosing cells (opens the original in a new tab)
Sagan L (1967). Journal of Theoretical Biology 14.
Lynn Margulis (then Sagan) argued that mitochondria and plastids descend from engulfed bacteria.
Historical paperTheory or modelInduction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors (opens the original in a new tab)
Takahashi K, Yamanaka S (2006). Cell 126:663-676.
Peer-reviewedPrimary researchRevised estimates for the number of human and bacteria cells in the body (opens the original in a new tab)
Sender R, Fuchs S, Milo R (2016). PLOS Biology 14:e1002533.
About 3.0 × 10^13 human cells and 3.8 × 10^13 bacteria in a 70 kg reference adult.
Peer-reviewedPrimary researchAn estimation of the number of cells in the human body (opens the original in a new tab)
Bianconi E, Piovesan A, Facchin F, et al. (2013). Annals of Human Biology 40:463-471.
Organ-by-organ estimate of about 3.72 × 10^13 cells.
Peer-reviewedPrimary research