What organelles is like a system of roads?

The endoplasmic reticulum (ER) is often compared to a system of roads within a cell. It forms a network of membranes that facilitate the transport of proteins and lipids throughout the cell, much like roads enable the movement of vehicles in a city. The rough ER, studded with ribosomes, is involved in protein synthesis, while the smooth ER is associated with lipid production and detoxification. Together, they help distribute essential materials to various parts of the cell.