The assembly of proteins takes place in the cytoplasm of a cell. There are three main steps. In initiation, far left, all the necessary parts of the process are brought together by a small molecule called a ribosome. During elongation, amino acids, the building blocks of proteins, are joined to one another in a long chain. The sequence in which the amino acids are added is determined by messenger, messenger ribonucleic acid RNA (mRNA), a transcribed copy of the cell's deoxyribonucleic acid DNA. Termination, far right, takes place when the mRNA sequence contains one of several "stop" codons. At these, the ribosome-mRNA complex binds a release factor that causes release of the completed (protein) chain of amino acids. The released chain is called the primary structure of a protein. This paper outlines simple methods for students and teachers alike to help in understand the mechanism of protein synthesis in a living cell. (Contains 3 figures.)