The main chemical components of ribosomes are protein and RNA. The ratio of protein and RNA is 1:1. It contains small amount of metal ions Mg++, Ca++, Mn++ etc. The 70S ribosome contains 3 rRNAs (5S, 16S and 23S) and 52 types of proteins. The 80S ribosome contains 4 rRNAs (5S, 5.8S, 18S and 28S) and 80 types of proteins.