nucleolus

American  

[noo-klee-uh-luhs, nyoo-] / nuˈkli ə ləs, nyu- /

noun

Cell Biology.

plural

nucleoli

1. a conspicuous, rounded body within the nucleus of a cell.

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nucleolus British  

/ ˌnjuːklɪˈəʊləs /

noun

1. Also called: nucleole.  a small rounded body within a resting nucleus that contains RNA and proteins and is involved in the production of ribosomes

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nucleolus Scientific  

/ no̅o̅-klē′ə-ləs /

plural

nucleoli

1. A small, typically spherical granular body located in the nucleus of a eukaryotic cell, composed largely of protein and RNA. When the cell is not undergoing division, loops of DNA from one or more chromosomes extend into the nucleolus and direct the synthesis of ribosomal RNA and the formation of ribosomes. The ribosomes are eventually transferred out of the nucleus via pores in the nuclear envelope into the cytoplasm.

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Other Word Forms

• nucleolar adjective

Etymology

Origin of nucleolus

1835–45; < Late Latin: small kernel, equivalent to nucle ( us ) kernel ( nucleus ) + -olus -ole ¹