Here's why:

* Structure: The Golgi apparatus is made up of flattened, membrane-bound sacs called cisternae. These cisternae are stacked on top of each other, and they are interconnected by a network of tubules.

* Function: The membrane of the Golgi apparatus plays a crucial role in its function. It helps to:

* Compartmentalize: The membrane creates separate compartments within the Golgi, allowing different enzymes and processes to occur in different areas.

* Transport: The membrane facilitates the movement of materials (proteins, lipids, etc.) through the Golgi.

* Modify: The membrane provides a surface for the modification and sorting of proteins and other molecules as they move through the Golgi.

So, the Golgi apparatus is a complex organelle with a membrane system that is essential for its function.