[yoo-kar-ee-oht, -ee-uh
t] 
| any organism having as its fundamental structural unit a cell type that contains specialized organelles in the cytoplasm, a membrane-bound nucleus enclosing genetic material organized into chromosomes, and an elaborate system of division by mitosis or meiosis, characteristic of all life forms except bacteria, blue-green algae, and other primitive microorganisms. |
[yoo-kar-ee-ot-ik] , adjective | eu·kar·y·ote also eu·car·y·ote (yōō-kār'ē-ōt, -ē-ət) n. A single-celled or multicellular organism whose cells contain a distinct membrane-bound nucleus. [eu- + Greek karuōtos, having nuts (from karuon, nut; see kar- in Indo-European roots).] eu·kar'y·ot'ic (-ŏt'ĭk) adj. |
An organism whose cells contain a nucleus. All multicelled organisms are eukaryotes, as is one superkingdom of single-celled organisms. Eukaryotes also have organelles enclosed by membranes. (Compare prokaryote.)
Note: Eukaryotes evolved in a process in which one early prokaryote consumed another, forming a more complex structure.
Note: The word eukaryote comes from the Greek for “true nucleus.”
eukaryote eu·kar·y·ote or eu·car·y·ote (y&oomacr;-kār'ē-ōt, -ē-ət)
n.
A single-celled or multicellular organism whose cells contain a distinct membrane-bound nucleus.
eukaryote (y -kār'ē-ōt) Pronunciation Key
An organism whose cells contain a nucleus surrounded by a membrane and whose DNA is bound together by proteins (histones) into chromosomes. The cells of eukaryotes also contain an endoplasmic reticulum and numerous specialized organelles not present in prokaryotes, especially mitochondria, Golgi bodies, and lysosomes. The organelles are enclosed in a three-part membrane (called a unit membrane) consisting of a lipid layer sandwiched between two protein layers. All organisms except for bacteria and archaea are eukaryotes. Compare prokaryote. eukaryotic adjective |
