Final answer:
The false statement is that intermediate filaments rupture under stress. They are actually resistant to tension and are integral for maintaining cell structure and resisting forces that pull cells apart.
Step-by-step explanation:
The statement about intermediate filaments that is not true is: A. They rupture under stress. Intermediate filaments, including those comprised of keratin, are known for their high tensile strength, meaning they are resistant to tension and do not easily rupture under stress. Instead, they help maintain cell shape and structure, provide support for nuclear positioning, and are involved in cell-to-cell adhesion through structures like desmosomes.
Intermediate filaments are indeed wider than actin filaments and do not have polarity, unlike microfilaments and microtubules that are polar and play roles in intracellular movement and transport. Alterations in intermediate filaments have been associated with premature aging in certain genetic disorders, pointing to their crucial role in maintaining cellular integrity.