Final answer:
Toxic APP fragments are generated in the endoplasmic reticulum. The endomembrane system, which includes the endoplasmic reticulum and the Golgi apparatus, plays a vital role in protein synthesis, modification, and transport, while lysosomes break down waste materials. Mitochondria supply the energy needed for these processes.
Step-by-step explanation:
Toxic amyloid-beta (Aβ) peptide fragments associated with Alzheimer's disease are generated by the cleavage of the amyloid precursor protein (APP) through certain enzymes in cellular organelles. The cleavage process does not take place in the ribosomes, mitochondria, or the Golgi apparatus. Instead, these fragments are generated in the membrane of the endoplasmic reticulum. Therefore, the correct answer is (c) Endoplasmic reticulum.
In eukaryotic cells, the endomembrane system is responsible for the modulation, packaging, and transportation of proteins and lipids. This system includes the nuclear envelope, lysosomes, vesicles, the endoplasmic reticulum, and the Golgi apparatus. The rough endoplasmic reticulum, with attached ribosomes, is the site of protein synthesis. After synthesis, these proteins may be transferred to the Golgi apparatus, where they undergo further modifications and packaging. Then, they may be distributed throughout the cell or secreted outside the cell. Lysosomes can break down waste materials and recycle cellular components, while mitochondria provide the energy required for these processes through ATP production, justifying their nickname as the cell's 'power plants'.