What does nucleolar mean?
Nucleolar is an adjective meaning relating to the nucleolus, a dense region inside a cell nucleus. The nucleolus is responsible for producing ribosomal RNA and assembling ribosomal subunits, making it essential to the cell's ability to make proteins. In technical writing, nucleolar can describe structures, proteins, regions, or processes associated with this organelle. For example, a nucleolar organizer is a chromosomal region containing genes involved in nucleolus formation, while a nucleolar protein may be one that localizes to or functions within the nucleolus. The word belongs primarily to cell and molecular biology and is less common in general speech. It should not be confused with nuclear, which applies more broadly to the nucleus or to atomic nuclei, or with nucleolus, which is the noun naming the structure itself.
adjectiveRelating to or characteristic of a nucleolus, the dense structure within a cell nucleus in which ribosomal RNA is synthesized and ribosome assembly begins.
- Relating to or characteristic of a nucleolus, especially the part of a cell nucleus where ribosomal RNA is produced and ribosome assembly begins.
"The fluorescent stain highlighted the cell's nucleolar region."
"Researchers used a fluorescent marker to label the nucleolar region in the dividing cell."
"The nucleolar organizer region contains the genes needed for forming the cell's nucleolus."
A cell's nucleolus is its ribosomal assembly line—and “nucleolar” is the adjective for this tiny, busy hub.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
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How nucleolar is actually used
This is a specialized biological adjective used mainly in cell biology, molecular biology, and related technical writing. It normally appears before a noun and is much more specific than “nuclear.”
Easily confused with nucleolar
Nucleolar specifically relates to the nucleolus, a structure inside the cell nucleus, whereas nuclear relates more broadly to the nucleus or to atomic nuclei.
Nucleolus is the noun naming the cellular structure, while nucleolar is the adjective describing it.