Final answer:
The component not part of the endomembrane system is mitochondria. The system includes nuclear envelope, ER, Golgi apparatus, lysosomes, vesicles, and the plasma membrane.
Step-by-step explanation:
Among the options provided, the component that is not a part of the endomembrane system is c) Mitochondria. The endomembrane system consists of several interconnected organelles, including the nuclear envelope, the endoplasmic reticulum (ER), the Golgi apparatus, lysosomes, vesicles, and the plasma membrane. These components work in synergy to modify, package, tag, and transport proteins and lipids that form the membranes. The mitochondria, however, are not part of this system and are instead believed to have originated from an endosymbiotic relationship with a prokaryotic organism.