cellule

The term cellule is French for cell; in biology it denotes the basic unit of life, the structural and functional unit of all organisms. The word derives from Latin cellula meaning a small room.

In biology there are prokaryotic cells (bacteria and archaea) that lack a cell nucleus, and eukaryotic cells (animals, plants, fungi, and protists) that possess a nucleus and a range of membrane-bound organelles. All cells have a plasma membrane, cytoplasm, and genetic material, but their organization and complexity differ.

Key organelles and features of eukaryotic cells include the nucleus, which houses DNA; mitochondria for energy production; ribosomes for protein synthesis; the endoplasmic reticulum and Golgi apparatus for protein and lipid processing and trafficking; lysosomes and peroxisomes for digestion and waste processing; chloroplasts in plants and algae for photosynthesis; and the cytoskeleton, which provides structure and pathways for transport. The cell membrane regulates exchange with the environment and participates in signaling and homeostasis.

Cell theory states that all living organisms are composed of one or more cells, that cells are the basic unit of life, and that new cells arise from pre-existing cells. Cells divide by mitosis and meiosis in eukaryotes, while prokaryotes reproduce by binary fission; stem cells can differentiate into multiple cell types.

Beyond biology, cellule also has non-scientific meanings in French, referring to a small room or compartment, and to a small organizational unit within a larger group, such as a research cellule or, in security contexts, a clandestine cell.