- a conspicuous, rounded body within the nucleus of a cell.
Origin of nucleolus
Examples from the Web for nucleoli
Historical Examples of nucleoli
Highly refracting points or nucleoli were visible in their anterior.Parasites
T. Spencer Cobbold
Within the nucleus are often to be found one or two nucleoli with a relatively thick and deeply stained membrane.Histology of the Blood
The above mode of increase for the nucleoli appears to be exceptional.The Works of Francis Maitland Balfour, Volume 1
Francis Maitland Balfour
The aberrant bodies in these figures are probably remains of the nucleoli; they are found only in iron-hæmatoxylin preparations.
Partial rest stage between first and second maturation divisions, two nucleoli present.
- a small rounded body within a resting nucleus that contains RNA and proteins and is involved in the production of ribosomesAlso called: nucleole
Word Origin for nucleolus
1845, from Latin nucleolus, literally "a little nut," diminutive of nucleus (see nucleus).
- A small, typically round granular body composed of protein and RNA in the nucleus of a cell, usually associated with a specific chromosomal site and involved in ribosomal RNA synthesis and the formation of ribosomes.
- 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.