nucleolus

American  

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

noun

Cell Biology.

nucleoli plural

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 /

nucleoli plural

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

Derived Forms

• nucleolar
  adjective

Inflected Forms

Nouns

• nucleoli
  plural

Etymology

Origin of nucleolus

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

Explanation

A nucleolus is the largest structure within the nucleus of a eukaryotic cell. It's the job of a nucleolus to make RNA and ribosomes. In a eukaryote, a cell whose nucleus is contained within a membrane, the nucleolus plays a vital role. It's here that ribosomes, tiny cell machines that produce important proteins, are made. RNA — which works by taking the information in DNA and translating it into proteins — also comes from the nucleolus. Nucleolus basically means "smaller nucleus," from a Latin word meaning "little nut."

Example Sentences

See Examples For:

nucleolus nucleoli

The secret to cellular youth may depend on keeping the nucleolus -- a condensed structure inside the nucleus of a cell -- small, according to Weill Cornell Medicine investigators.

From Science Daily ● Nov. 25, 2024

The researchers discovered that tethering the nucleolus was enough to keep it compact, and small nucleoli delayed aging to about the same extent as calorie restriction.

From Science Daily ● Nov. 25, 2024

"The advantage of our system is that we could isolate the nucleolus size from all of the other effects of anti-aging strategies," Dr. Gutierrez said.

From Science Daily ● Nov. 25, 2024

If the nucleolus were not able to carry out its function, what other cellular organelles would be affected?

From Textbooks ● Jun. 9, 2022

In a knot of the network is contained the dark, stiff, opaque nuclear corpuscle or nucleolus.

From The Evolution of Man — Volume 1 by Haeckel, Ernst Heinrich Philipp August

Dr. Tyler and postdoctoral fellow Dr. J. Ignacio Gutierrez, the first author of the paper, suspected that keeping nucleoli small could delay aging.

From Science Daily ● Nov. 25, 2024

In organisms from yeast to worms to humans, nucleoli expand during aging.

From Science Daily ● Nov. 25, 2024

This caused RAG1 to get trapped within cell nucleoli instead of facilitating the gene rearrangements that build immune diversity.

From Science Daily ● May 24, 2024

The nucleus contains one or more nucleoli, which serve as sites for ribosome synthesis.

From Textbooks ● Jun. 19, 2013

During this process of the formation of the chromosomes the nucleoli disappear, sometimes being absorbed apparently in the chromosomes, and sometimes being ejected into the cell body, where they disappear.

From The Story of the Living Machine A Review of the Conclusions of Modern Biology in Regard to the Mechanism Which Controls the Phenomena of Living Activity by Conn, H. W. (Herbert William)