Final answer:
Microtubules and microfilaments both have intrinsic directionality, with distinct '+' and '−' ends, important for cellular processes such as movement and division, despite having different subunit compositions.
Step-by-step explanation:
Microtubules and microfilaments are similar in that both have intrinsic directionality because one end of each structure is distinct from the other end. Although microtubules form hollow tubes and are composed of polymerized dimers of α-tubulin and β-tubulin, and microfilaments are composed of thin actin chains, they share the characteristic of polarity. The α- and β- subunits in microtubules and actin monomers in microfilaments arrange in a way that gives each filament a '+' and '−' end, which is essential for their functions in processes like cell movement and division.
This directionality enables them to participate in dynamic assembly and disassembly, essential for cellular activities such as vesicle transport and chromatid separation during mitosis.