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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 ...
Rudolf Ludwig Carl Virchow (/ ˈvɪərkoʊ, ˈfɪərxoʊ / VEER-koh, FEER-khoh, [1] German: [ˈʁuːdɔlf ˈvɪʁço, - ˈfɪʁço]; [2][3] 13 October 1821 – 5 September 1902) was a German physician, anthropologist, pathologist, prehistorian, biologist, writer, editor, and politician. He is known as "the father of modern pathology " and as ...
He coined the term cell (from Latin cellula, meaning "small room" [41]) in his book Micrographia (1665). [42] [40] 1839: Theodor Schwann [43] and Matthias Jakob Schleiden elucidated the principle that plants and animals are made of cells, concluding that cells are a common unit of structure and development, and thus founding the cell theory.
Ramón y Cajal's drawing of the cells of the chick cerebellum, from Estructura de los centros nerviosos de las aves, Madrid, 1905. The neuron doctrine is the concept that the nervous system is made up of discrete individual cells, a discovery due to decisive neuro-anatomical work of Santiago Ramón y Cajal and later presented by, among others, H. Waldeyer-Hartz. [1]
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
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 ...
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 theory states that cells are the fundamental units of life, that all living things are composed of one or more cells, and that all cells arise from preexisting cells through cell division. [40] Most cells are very small, with diameters ranging from 1 to 100 micrometers and are therefore only visible under a light or electron microscope. [41]