eukaryote

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eukaryote Organism whose cells have a membrane-bound nucleus, with DNA contained in chromosomes. Making up one of the three domains, eukaryotes include all animals, plants, fungus, and Protoctista. They have a complex cytoplasm with an endoplasmic reticulum, and most of them possess mitochondria. Most plants and algae also possess chloroplasts. Other structures specific to eukaryotic cells include microtubules, Golgi bodies, and membrane-bound flagella. See also Golgi body; kingdom; mitochondrion; prokaryote

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eukaryote (yōōkâr´ē-ōt´), a cell or organism composed of cells that have a membrane-bound nucleus and organelles (mitochondria, chloroplasts; see cell, in biology) and genetic material organized in chromosomes in which the DNA is combined with histone proteins. Eukaryotes are contrasted with the prokaryotes (see Monera). Eukaryotes formed through the merger of prokaryotes, which predate them in the fossil record by some 2 billion years. In the five-kingdom system of classification, the eukaryotes have comprised the taxonomic kingdoms Protista, Fungi, Plantae (see plant), and Animalia (see animal). In a recently proposed system they are called the eukarya and classified as an overarching group (domain) above the kingdom level.

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eukaryote An organism comprising cells that have a distinct nucleus enveloped by a double membrane, and other features including double-membraned mitochondria and 80S ribosomes in the fluid of the cytoplasm (i.e. all protists, fungi, plants, and animals). The first eukaryotes were almost certainly green algae, and what appear to be their microscopic remains appear in Precambrian sediments dating from a little less than 1500 Ma ago.

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eukaryote (adj. eukaryotic) Organism with cells that have a distinct nucleus, i.e. all protists, fungi, plants, and animals. The first eukaryotes were almost certainly green algae (Chlorophyta), and what appear to be their microscopic remains appear in Precambrian sediments dating from a little less than 1500 Ma ago. Compare PROKARYOTE.

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eukaryote An organism whose cells have a distinct nucleus (i.e. all protists, fungi, plants, and animals). The first eukaryotes were almost certainly green algae (Chlorophyceae) and what appear to be their microscopic remains occur in Precambrian sediments dating from a little less than 1500 Ma ago.

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eukaryote An organism whose cells have a distinct nucleus enveloped by a double membrane, and other features including double-membraned mitochondria and 80S ribosomes in the fluid of the cytoplasm (i.e. all protists, fungi, plants, and animals). The first eukaryotes were almost certainly green algae (Chlorophyceae) and what appear to be their microscopic remains appear in Proterozoic sediments dating from a little less than 1500 Ma ago.

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eukaryote (eucaryote) An organism consisting of cells in which the genetic material is contained within a distinct nucleus. All organisms except bacteria are eukaryotes. See Eukarya. Compare prokaryote.