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Eukaryotes are organisms that range from microscopic single cells, such as picozoans under 3 micrometres across, [ 7] to animals like the blue whale, weighing up to 190 tonnes and measuring up to 33.6 metres (110 ft) long, [ 8] or plants like the coast redwood, up to 120 metres (390 ft) tall. [ 9]
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.
Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae. Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the ...
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 list of human cell types provides an enumeration and description of the various specialized cells found within the human body, highlighting their distinct functions, characteristics, and contributions to overall physiological processes. Cells may be classified [ 1] by their physiological function, histology (microscopic anatomy), [ 2 ...
Cell type. A cell type is a classification used to identify cells that share morphological or phenotypical features. [ 1] A multicellular organism may contain cells of a number of widely differing and specialized cell types, such as muscle cells and skin cells, that differ both in appearance and function yet have identical genomic sequences ...
Viral eukaryogenesis. Viral eukaryogenesis is the hypothesis that the cell nucleus of eukaryotic life forms evolved from a large DNA virus in a form of endosymbiosis within a methanogenic archaeon or a bacterium. The virus later evolved into the eukaryotic nucleus by acquiring genes from the host genome and eventually usurping its role.
A chromosome is a package of DNA with part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome -forming packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA ...