Final answer:
The movement of organelles in large eukaryotic cells is enabled by the cytoskeleton, a network of fibers that provides structural support and facilitates transport within the cell.
Step-by-step explanation:
Because eukaryotic cells are so large, movement of organelles via the cytoskeleton is critical. The cytoskeleton, composed of microfilaments, intermediate filaments, and microtubules, provides not only structural support but also acts as a network over which materials can be transported within the cell. It anchors organelles and facilitates their movement, for example, through processes such as exocytosis, where vesicles move to the plasma membrane to release their contents.
In contrast to the cytoskeleton, the endomembrane system is involved in the synthesis, modification, packaging, and transport of lipids and proteins and includes organelles such as the endoplasmic reticulum and Golgi apparatus. Although the endomembrane system collaborates closely with the cytoskeleton in the transport and distribution of cellular materials, it is the cytoskeletal network that is directly responsible for the physical movement of organelles within the cell's cytoplasm.