Final answer:
Intermediate filaments are found in desmosomes (Option C) where they provide mechanical support and maintain cell integrity, especially in muscle tissue. The mitotic spindle, which consists of microtubules, originates from the centrosome, not intermediate filaments. Option C. Desmosomes is the correct answer.
Step-by-step explanation:
Intermediate filaments are found in several cellular structures, but with respect to the options provided, the correct answer is that they are found in desmosomes (Option C). Intermediate filaments are primarily involved in maintaining cell shape and providing mechanical support for the cell.
For example, the intermediate filament protein desmin is present in desmosomes, which are cell-to-cell junctions particularly important in muscle tissue, binding muscle cells together and allowing them to withstand mechanical stress. Additionally, intermediate filaments made of keratin contribute to the structural integrity of hair, skin, and nails.
In contrast to the supportive role of intermediate filaments, the mitotic spindle, which plays a crucial part during cell division, is made of microtubules and arises from the centrosome (Option B from the reference information). The centrosome acts as a microtubule-organizing center in animal cells, from which the spindle fibers extend during mitosis to separate chromosomes.