Final answer:
Intermediate filaments do not have polarity, lacking 'plus' and 'minus' ends, which distinguishes them from microtubules and microfilaments, both of which have polar ends facilitating directional growth.
Step-by-step explanation:
Distinguishing Feature of Intermediate Filaments
Intermediate filaments, a component of the cell's cytoskeleton, differ from microtubules and microfilaments in one significant aspect – they lack polarity. This means that unlike microtubules and actin filaments, intermediate filament subunits do not have 'plus' and 'minus' ends, rendering them non-polar. Microtubules and microfilaments can grow at one end faster than the other due to their polarity, but this is not the case for intermediate filaments.
While microtubules are small hollow tubes aiding in organelle movement and cell division, and microfilaments function in movement and muscle cell contraction, intermediate filaments are primarily involved in maintaining cell shape and structural integrity. Keratin, a type of fibrous protein, is a primary component of intermediate filaments, providing resistance to tension in cells.