What critical role do microtubules play in cell division?

Microtubules play a crucial role in cell division by forming the mitotic spindle, a structure essential for the accurate separation of sister chromatids during mitosis. The mitotic spindle is composed of microtubules that extend from the centrosomes to the kinetochores of each chromatid. During the metaphase stage of cell division, the spindle aligns the chromosomes at the cell's equator, setting them up for separation.

When the cell progresses into anaphase, the microtubules shorten, pulling the sister chromatids apart towards opposite poles of the cell. This process ensures that each daughter cell receives an identical set of chromosomes, which is vital for maintaining genetic consistency following cell division.

In contrast, while the other options mention important cellular processes, they do not accurately reflect the specific function of microtubules in the context of cell division. They do not assist in forming the cell membrane, regulate metabolism, or initiate DNA synthesis. Thus, the formation of the mitotic spindle by microtubules is paramount for successful cell division and the maintenance of genetic stability.