The rough ER is composed of an interconnected network of flattened, membrane-enclosed sacs known as cisternae. The smooth ER has a more interconnected tubular structure. An ER tubule can range in size ...

Cells have extensive sets of intracellular membranes, which together compose the endomembrane system. The endomembrane system was first discovered in the late 1800s when scientist Camillo Golgi ...

A protein's function directly depends on its folded structure ... that bind to calcium in the sarcoplasmic reticulum — a specialized type of endoplasmic reticulum found in muscle cells.