Ribosomes are the protein factories of cells. They produce proteins on the basis of encoded blueprints. The blueprint is encoded with “base letters” on the DNA. Each of these letters (e.g. AGT) forms a code word. The ribosomes identify each three-letter word as a short form of a building instruction.

For instance, the instruction of the three-letter code “AGT” is as follows: “Take the building block called serine and attach it to the already existing chain of building blocks.” Subsequent codes follow, attaching building block to building block to form a protein. Finally, a code word has its turn which signals to the protein factory: “Now the protein is completed.”