What does a ribosome do

A ribosome is a complex molecular structure with a main role in synthesis of proteins. It is the site where protein synthesis occurs. Ribosomes consists of two subunits: the small subunit and the large subunit, each composed of ribosomal RNA (rRNA) and proteins. The small ribosomal subunit reads the messenger RNA (mRNA) while the large one joins amino acids carried by the transfer RNA (tRNA) to form a polypeptide chain.