When a cell divides, each daughter cell receives an exact copy of the parent gene. The structure of the double chain ensures the stability and permanence required by hereditary material. But the model can also be read in another way. Along the length of the chain, the letters are grouped in threes in coded words. An alphabet of four letters allows the formation of more than 30 different words and the sequence in the gene of such words provides the structural information for an enzyme or some other protein.
Proteins are also chain molecules built up from twenty or so different types of building blocks.
To each of these building blocks there corresponds a chemical code word of three letters. The gene thus contains information on the number, nature, and order of the building blocks in a particular protein. Thus it was already clear that the hereditary blueprint contained the collective structural information for all substances necessary for the functions of the living cell. It was not known how the genetic information was put into effect or transformed into chemical activity. As to the function of the genes, it was thought that they participated in a sort of procreative act when the new cell came into being, producing new substances necessary for the life of the cell, but subsequently lying dormant until the next cell division.