ribosome

American  

[rahy-buh-sohm] / ˈraɪ bəˌsoʊm /

noun

Cell Biology.

1. a tiny, somewhat mitten-shaped organelle occurring in great numbers in the cell cytoplasm either freely, in small clusters, or attached to the outer surfaces of endoplasmic reticula, and functioning as the site of protein manufacture.

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ribosome British  

/ ˈraɪbəˌsəʊm /

noun

1. any of numerous minute particles in the cytoplasm of cells, either free or attached to the endoplasmic reticulum, that contain RNA and protein and are the site of protein synthesis

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ribosome Scientific  

/ rī′bə-sōm′ /

1. A sphere-shaped structure within the cytoplasm of a cell that is composed of RNA and protein and is the site of protein synthesis. Ribosomes are free in the cytoplasm and often attached to the membrane of the endoplasmic reticulum. Ribosomes exist in both eukaryotic and prokaryotic cells. Plastids and mitochondria in eukaryotic cells have smaller ribosomes similar to those of prokaryotes.

2. See more at cell

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ribosome Cultural  

1. A small, ball-like structure in the cell, made of proteins and RNA molecules, that serves as a platform on which the cell's proteins are made.

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Other Word Forms

• ribosomal
  adjective

Etymology

Origin of ribosome

First recorded in 1955–60; ribo(se) + -some ³

Explanation

A ribosome is a tiny part of a cell with the specific job of making protein. All living cells contain ribosomes. Ribosomes are the organelles responsible for RNA translation, the process of building protein out of amino acids using RNA. The ribosome translates code it finds in strands of messenger RNA, using it to form the new proteins needed by the cell. Microbiologist Richard B. Roberts coined ribosome from the complex scientific phrase "ribonucleoprotein particles of the microsome fraction."

Example Sentences

Additional analysis using selective ribosome profiling showed that DHX29 is more likely to associate with ribosomes that are reading non-optimal codons.

From Science Daily • Apr. 9, 2026

Using cryo-electron microscopy, the team was able to observe how DHX29 physically interacts with the 80S ribosome, the cellular machinery responsible for protein production.

From Science Daily • Apr. 9, 2026

"We know there is an interaction between the RNAP, the ribosome, transcription factors, proteins and mRNA," said U-M senior scientist Adrien Chauvier, one of four co-leaders of the study.

From Science Daily • Nov. 28, 2024

This group didn’t conduct experiments of its own, but plumbed what others had done, first combing through ribosome profiling papers.

From Science Magazine • Nov. 24, 2024

The addition of the ion was critical: with the solution supplemented with magnesium, the ribosome remained glued together, and Brenner and Jacob finally purified a minuscule amount of the messenger molecule out of bacterial cells.

From "The Gene" by Siddhartha Mukherjee