The cell is a complex system with specialized organelles and cellular machinery. The cell in an organisms have the same genetic material (DNA), but each cells only produce the proteins that they need in the moment or function that they are needed, that's because the cell have a "intelligent" intrecellular signaling and organization system. Some examples of these hability of the cells to control the production and liberation of proteins is the cell differentiation and the case of cells that have the function of producing protein hormones (insulin, glucagon, pituitary hormones, and hypothalamic hormones), it is important to the cells to have the control of which they produce because one cell have more autonomy and with only one genetic code an organism com be self-sufficient (molecular) and with internal protein variability.