Ribosomes are organelles that play a key role in the manufacture of proteins. Found throughout the cell, ribosomes are composed of ribosomal ribonucleic acid (rRNA) and proteins. They are the sites of protein synthesis.

Although Robert Hooke first used a light microscope to look at cells in 1665, it was only during the last few decades that the cell's organelles were discovered. This is primarily because light microscopes do not have the magnifying power required to see these tiny structures. Using an electron microscope, scientists have been able to see most of the cells substructures, including the ribosomes.

Ribosomes are composed of a variety of proteins and rRNA. They are organized in two functional subunits that are constructed in the cell's nucleolus. One is a small...