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A prokaryote (/ p r oʊ ˈ k ær i oʊ t,-ə t /, less commonly spelled procaryote) [1] is a single-cell organism whose cell lacks a nucleus and other membrane-bound organelles. [2] The word prokaryote comes from the Ancient Greek πρό ( pró ) 'before' and κάρυον ( káruon ) 'nut, kernel'.
Prokaryotic cells were the first form of life on Earth, characterized by having vital biological processes including cell signaling. They are simpler and smaller than eukaryotic cells, and lack a nucleus, and other membrane-bound organelles. The DNA of a prokaryotic cell consists of a single circular chromosome that is in direct contact with ...
Cell biology is the study of the structural and functional units of cells. Cell biology encompasses both prokaryotic and eukaryotic cells and has many subtopics which may include the study of cell metabolism, cell communication, cell cycle, biochemistry, and cell composition.
The prokaryotic cytoskeletal elements are matched with their eukaryotic homologue and hypothesized cellular function. [1] The prokaryotic cytoskeleton is the collective name for all structural filaments in prokaryotes. It was once thought that prokaryotic cells did not possess cytoskeletons, but advances in visualization technology 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 ...
Nucleoid. The nucleoid (meaning nucleus -like) is an irregularly shaped region within the prokaryotic cell that contains all or most of the genetic material. [1][2][3] The chromosome of a typical prokaryote is circular, and its length is very large compared to the cell dimensions, so it needs to be compacted in order to fit.
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 ...
The term "bacteria" was traditionally applied to all microscopic, single-cell prokaryotes. However, molecular systematics showed prokaryotic life to consist of two separate domains, originally called Eubacteria and Archaebacteria, but now called Bacteria and Archaea that evolved independently from an ancient common ancestor. [4]