AAT Bioquest

What are ribosomes?

Posted October 13, 2022


Ribosomes, also known as Palade granules, are organelles that are made up of both RNA and protein, whose function is to assist in protein synthesis. Essentially, ribosomes create a factory for protein synthesis in cells. Ribosomes are extremely small in size, ranging from 20 to 30 nm. They are granular shaped and are non-membranous organelles. The average mammalian cell has approximately 10 million ribosomes.  

Ribosomes were discovered in 1955 by George E. Palade, hence the alternative name  Palade granules. Each ribosome has a large subunit as well as a smaller subunit. Together, they create a single unit containing several ribosomal RNA molecules and dozens of proteins. Lastly, there are two types of ribosomes, prokaryotic and eukaryotic.   

Additional resources

Ribosome Structure, Function, and Early Evolution

Cell Structures and Organelles