Final answer:
Microtubules are bigger than intermediate filaments, with diameters of about 25 nm compared to 8-10 nm for intermediate filaments. Intermediate filaments provide structural support, while microtubules are involved in cell shape and mobility.
Step-by-step explanation:
Intermediate filaments have a diameter that falls between microfilaments and microtubules, therefore, microtubules are bigger than intermediate filaments. Specifically, intermediate filaments typically range from 8 to 10 nm in diameter while microtubules are thicker at about 25 nm. Intermediate filaments are composed of fibrous proteins like keratin, wound together, and serve primarily to provide structural support and resist tensile stresses. In contrast, microtubules are hollow tubes made from α-tubulin and β-tubulin dimers, playing a key role in maintaining cell shape, enabling cell motility, and guiding organelle movement, as well as chromosomal separation during cell division.