Ribosomes are ribonucleoprotein complexes found in both prokaryotic (70S) and eukaryotic (80S) cells. They are made up of ribosomal RNA and 80 different types of proteins. There are two subunits, the smaller subunit has sedimentation coefficients of 30S and 40S, for prokaryotes and eukaryotes, respectively. The larger subunits have sedimentation coefficients of 50S and 60S, for prokaryotes and eukaryotes, respectively.