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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.
Symbiogenesis ( endosymbiotic theory, or serial endosymbiotic theory [2]) is the leading evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms. [3] The theory holds that mitochondria, plastids such as chloroplasts, and possibly other organelles of eukaryotic cells are descended from formerly free-living prokaryotes ...
Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. 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. Cell biology is the study of the structural and functional units of cells. Cell biology encompasses both prokaryotic and ...
The eukaryotic cell seems to have evolved from a symbiotic community of prokaryotic cells. DNA-bearing organelles like mitochondria and chloroplasts are remnants of ancient symbiotic oxygen-breathing bacteria and cyanobacteria, respectively, where at least part of the rest of the cell may have been derived from an ancestral archaean prokaryote ...
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 ...
Clonal selection theory of lymphocytes: 1) A hematopoietic stem cell undergoes differentiation and genetic rearrangement to produce. 2) immature lymphocytes with many different antigen receptors. Those that bind to. 3) antigens from the body's own tissues are destroyed, while the rest mature into. 4) inactive lymphocytes.
Matthias Jakob Schleiden ( German: [maˈtiːas ˈjaːkɔp ˈʃlaɪdn̩]; [1] [2] 5 April 1804 – 23 June 1881) was a German botanist and co-founder of cell theory, along with Theodor Schwann and Rudolf Virchow. He published some poems and non-scientific work under the pseudonym Ernst. [3]