Eukaryote
Say it: yoo-KAR-ee-oht
A eukaryote is an organism whose cells keep their DNA inside a membrane-bound nucleus and contain other membrane-bound organelles.
Also: eukaryotes, eucaryote, eukaryotic cell
Definition
What is a eukaryote?
A eukaryote is any organism built from cells that have a true nucleus, a compartment wrapped in a double membrane that holds the cell's chromosomes. Animals, plants, fungi and protists such as algae and amoebas are all eukaryotes, together forming the domain Eukarya. Some, like yeast, live as single cells, while others are made of many cells.
Besides the nucleus, eukaryotic cells contain an internal system of membranes and organelles, including the endoplasmic reticulum, the Golgi apparatus, lysosomes and, in nearly all cases, mitochondria; plant and algal cells also have chloroplasts. Their DNA is arranged as several linear chromosomes wound around proteins called histones, the ribosomes in their cytoplasm (80S) are larger than prokaryotic ones (70S), and a cytoskeleton of protein filaments gives the cell its shape and moves material around inside it.
Eukaryotic cells are usually far larger than prokaryotic cells, which is one reason they need internal compartments and transport systems. Mitochondria and chloroplasts are thought to descend from bacteria that were engulfed by an ancestral cell and kept as partners, an idea known as endosymbiotic theory.
Word parts
Where does the word “eukaryote” come from?
- eu-
- true, wellGreek eu
- kary-
- nut, kernel (here, the nucleus)Greek karyon
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Related
Terms that go with it
- ProkaryoteA prokaryote is a usually single-celled organism, a bacterium or an archaeon, whose cell has no nucleus or other membrane-bound organelles.
- NucleusThe nucleus is the membrane-bound organelle that holds a eukaryotic cell's chromosomes and controls which of its genes are used and when.
- OrganelleAn organelle is a specialized structure inside a cell, usually wrapped in its own membrane, that carries out a particular job for the cell.
- MitochondrionA mitochondrion is a double-membraned organelle that makes most of a eukaryotic cell's ATP by breaking down fuel molecules with oxygen.
- CellA cell is the smallest unit that can carry out all the processes of life, enclosed by a membrane and holding its own genetic material.
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Checked against
Written for biofideX in plain words, after checking these references:
- OpenStax Biology 2e, 4.3 Eukaryotic Cells
- OpenStax Microbiology, 3.4 Unique Characteristics of Eukaryotic Cells
- MeSH (NLM): Eukaryotic Cells
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