Ribosomes are the sites in a cell in which protein synthesis takes place. Cells have many ribosomes, and the exact number depends on how active a particular cell is in synthesizing proteins.

In contrast, eukaryotic cells have 80S ribosomes, which are larger and more complex and also consist of two subunits: a 40S (small) subunit and a 60S (large) subunit. The 40S subunit contains an ...