I had been trained as a nucleus-centered biologist as surely as Copernicus had been trained as an Earth-centered astronomer, so it was with a jolt that I realized that the gene-containing nucleus does not program the cell. Environmental data is entered into the cell/computer via the membrane’s receptors, which represent the cell’s “keyboard.” Receptors trigger the membrane’s effector proteins, which act as the cell/computer’s “Central Processing Unit” (CPU).
