eukaryote

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eukaryote

(yo͞okâr`ē-ōt'), a cell or organism composed of cells that have a membrane-bound nucleus and organelles (mitochondria, chloroplasts; see cellcell,
in biology, the unit of structure and function of which all plants and animals are composed. The cell is the smallest unit in the living organism that is capable of integrating the essential life processes. There are many unicellular organisms, e.g.
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, in biology) and genetic material organized in chromosomes in which the DNA is combined with histonehistone
, any of a class of protein molecules found in the chromosomes of eukaryotic cells. They complex with the DNA (see nucleic acid) and pack the DNA into tight masses of chromatin, which have the structure of coiled coils, much like a tangled telephone cord.
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 proteins. Eukaryotes are contrasted with the prokaryotes (see MoneraMonera,
taxonomic kingdom that comprises the prokaryotes (bacteria and cyanobacteria). Prokaryotes are single-celled organisms that lack a membrane-bound nucleus and usually lack membrane-bound organelles (mitochondria, chloroplasts; see cell, in biology).
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). 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 classificationclassification,
in biology, the systematic categorization of organisms into a coherent scheme. The original purpose of biological classification, or systematics, was to organize the vast number of known plants and animals into categories that could be named, remembered, and
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, the eukaryotes have comprised the taxonomic kingdoms ProtistaProtista
or Protoctista
, in the five-kingdom system of classification, a kingdom comprising a variety of unicellular and some simple multinuclear and multicellular eukaryotic organisms.
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, FungiFungi
, kingdom of heterotrophic single-celled, multinucleated, or multicellular organisms, including yeasts, molds, and mushrooms. The organisms live as parasites, symbionts, or saprobes (see saprophyte).
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, Plantae (see plantplant,
any organism of the plant kingdom, as opposed to one of the animal kingdom or of the kingdoms Fungi, Protista, or Monera in the five-kingdom system of classification.
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), and Animalia (see animalanimal,
any member of the animal kingdom (kingdom Animalia), as distinguished from organisms of the plant kingdom (kingdom Plantae) and the kingdoms Fungi, Protista, and Monera in the five-kingdom system of classification.
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). In a recently proposed system they are called the eukarya and classified as an overarching group (domain) above the kingdom level.

Eukaryote

 

a single- and multiple-celled plant and animal organism in which the body of the cell, in contrast to the cells of a prokaryote, is differentiated into the cytoplasm and the nucleus enclosed by a membrane. The most recent system of the organic kingdom gives the eukaryotes the rank of a superkingdom (including the animal, mushroom, and plant kingdoms) and juxtaposes them to the superkingdom of the prokaryotes.

The genetic material of the nucleus of eukaryotes is organized into chromosomes that are capable of duplication and distribution through mitosis between daughter cells. The molecular basis of the chromosomes is deoxyribonucleic acid (DNA), which is closely associated with histones and other proteins. In most eukaryotes there is a typical sexual process, with the fusion of cell nuclei during fertilization and reduction division during meiosis. The cytoplasm of the cells of eukaryotes, in contrast to that of prokaryote cells, has a complex system of membranes that form an endoplasmotic network, the Golgi apparatus, the mitochondria, and other organoids.

eukaryote

[yü′kar·ē‚ōt]
(biology)
A cell with a definitive nucleus. Also spelled eucaryote.
References in periodicals archive ?
The eukaryotic membrane systems, including the nuclear envelope, then formed within the boundaries of this archaeal cell through the invagination of the outer membrane.
Synthetic chromosomes that damage yeast's evolutionary fitness or fail to produce viable yeast may teach researchers how chromosomes evolved and give clues about the minimal requirements for eukaryotic life, he says.
The final destination requires an exploration of symbioses within Deep Time, leading to the conclusion that modern ecosystems may not provide the best reference point for eukaryotic cell evolution.
While previous theories on mitochondrial origins argued that an anaerobic, sugar-metabolizing bacterial or eukaryotic host cell captured an aerobic bacterium to provide a better way of making ATP, Martin and Muller counter that the host was an archaeon whose metabolism resembled that of the methanogens crowding around the hydrogenosomes in the slide that so fascinated Martin.
Investigators probing this issue have been stymied because bacteria ar e so small and their chromosomes are more difficult to view than those of their eukaryotic counterparts.
The finding simplifies models for eukaryotic genetic activation and indicates key regulatory checkpoints in the process" says Michael Carey, a biochemist at the University of California, Los Angeles, School of Medicine.
In a volume dedicated to a pioneer in the study of DNA replication in eukaryotic (nucleated) cells, DePamphilis (National Institute of Child Health and Human Development, Bethesda, MD) introduces 36 chapters by international scientists working to understand how such cells replicate and repair their genomes.
University of California (Oakland, CA) has patented a method of screening large, complex, polyexonic eukaryotic genes such as the ATM gene for mutations and polymorphisms by an improved version of single strand conformation polymorphism electrophoresis that allows electrophoresis of two or three amplified segments in a single lane.
When Lake's program corrects for varying rates of genetic substitutions over millions of years, it takes one branch of the Archaebacteria, the Eocytes, and grafts it to the more rapidly evolving Eukaryotic limb.
Senesco" or the "Company") (AMEX:SNT) announced today that the Company's eukaryotic translation initiation Factor 5A-1 ("Factor 5A-1" or "eIF5A-1") gene technology reduced inflammation and inhibited apoptosis in mouse experiments conducted by W.
The first section covers the spread of microorganisms and the body's response to infection, and the next three sections outline properties of viruses, bacteria, and eukaryotic organisms.
The invention is directed toward the isolation, characterization and pharmacological use of mammalian adrenocorticotropic hormone receptor, the gene corresponding to this receptor, a recombinant eukaryotic expression construct capable of expressing a mammalian adrenocorticotropic hormone receptor in cultures of transformed eukaryotic cells and such cultures of transformed eukaryotic cells that synthesize mammalian adrenocorticotropic hormone receptor.