Final answer:
Ribosomes are small organelles composed of two subunits that are the sites of protein synthesis in cells. They bind to mRNA and tRNA to translate genetic information into proteins.
Step-by-step explanation:
Proteins are assembled on ribosomes, small organelles composed of two subunits. Ribosomes are integral to protein synthesis in all living cells and can be found in both prokaryotic and eukaryotic organisms. These organelles are made up of a large subunit and a small subunit, each consisting of ribosomal RNA (rRNA) and protein. The small subunit binds to the messenger RNA (mRNA), while the large subunit binds to transfer RNA (tRNA) and together they facilitate the translation of mRNA into a polypeptide chain—essentially assembling amino acids into proteins.