In 1950, physicists could not see the various constituents of matter, but they had physical theories that produced very good predictions of the behavior of these constituents. In contrast, in 1950, biologists could see many constituents of the biological cell, but the cell in its ensemble of parts appeared so complex that how these constituents behaved was a mystery. For half a century, however, many biologists considered the Golgi apparatus a staining artifact, and it was not until the 1950s and the use of the electron microscope in biology that the Golgi apparatus was finally confirmed as a real structure in cells. Still, at that time there was no clear detailed idea concerning how the Golgi apparatus contributed to the functioning of the cell, although it did seem to be involved in secretion, since it appeared more pronounced in secreting cells than in other cells. It took the remaining decades of this century for the story of the Golgi apparatus to be unfolded.
Golgi bodies are thus particularly abundant in secretory cells.
They consist of stacks of membranous sacs that are pinched off as Golgi vesicles for delivery to the exterior of the cell. In general, the endoplasmic reticulum is an extensive system of flattened membranous sacs traversing the cytoplasm of all eukaryotic cells and continuous with the envelope that surrounds the nucleus. A ribosome is a small particle, a complex of various ribonucleic acid component subunits and proteins that functions as the site of protein synthesis in the cell. The cytosol contains enzymes involved in metabolic pathways, whereas the ER cisternal space provides a route for the movement of materials through various intracellular compartments and, in some cases, to the cell exterior. The rough endoplasmic reticulum plays a central role in the synthesis of secretory proteins, integral membrane proteins, and proteins destined to reside in the lumen of the endoplasmic reticulum.