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In biology, cell theory is a scientific theory first formulated in the mid-nineteenth century, that living organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells. Cells are the basic unit of structure in all living organisms and also the basic unit ...
The cell is the basic structural and functional unit of all forms of life. Every cell consists of cytoplasm enclosed within a membrane; many cells contain organelles, each with a specific function. The term comes from the Latin word cellula meaning 'small room'. Most cells are only visible under a microscope.
Theodor Schwann (German pronunciation: [ˈteːodoːɐ̯ ˈʃvan]; [1][2] 7 December 1810 – 11 January 1882) was a German physician and physiologist. [3] His most significant contribution to biology is considered to be the extension of cell theory to animals. Other contributions include the discovery of Schwann cells in the peripheral nervous ...
History of cell membrane theory. Cell theory has its origins in seventeenth century microscopy observations, but it was nearly two hundred years before a complete cell membrane theory was developed to explain what separates cells from the outside world. By the 19th century it was accepted that some form of semi-permeable barrier must exist ...
Category. v. t. e. Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. [1][2] All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living and functioning of organisms. [3] Cell biology is the study of the structural ...
Last universal common ancestor. The last universal common ancestor (LUCA) is the hypothesized common ancestral cell from which the three domains of life, the Bacteria, the Archaea, and the Eukarya originated. The cell had a lipid bilayer; it possessed the genetic code and ribosomes which translated from DNA or RNA to proteins.
Illustration of Virchow's cell theory. Virchow is credited with several key discoveries. His most widely known scientific contribution is his cell theory, which built on the work of Theodor Schwann. He was one of the first to accept the work of Robert Remak, who showed that the origin of cells was the division of pre-existing cells. [29]
The initial development of the cell marked the passage from prebiotic chemistry to partitioned units resembling modern cells. The final transition to living entities that fulfill all the definitions of modern cells depended on the ability to evolve effectively by natural selection. This transition has been called the Darwinian transition.