Polar microtubules

Definition

Polar microtubules are spindle fibers that extend from the centrosomes towards the cell's center during mitosis. They help separate the chromosomes by pushing against each other to elongate the cell.

5 Must Know Facts For Your Next Test

1. Polar microtubules do not attach to chromosomes but interact with each other at the cell’s equator.
2. They originate from opposite spindle poles and overlap in the middle of the cell.
3. The primary function is to push against each other, helping to elongate and stabilize the mitotic spindle.
4. They play a critical role during anaphase B, where they help in separating chromatids by increasing cell length.
5. Motor proteins like kinesin move along polar microtubules, facilitating their sliding apart.

Review Questions

Related terms

Spindle Apparatus: The structure composed of microtubules that segregates chromosomes into daughter cells during mitosis.

Centrosome: The major microtubule-organizing center in animal cells, crucial for forming the spindle apparatus.

Kinetochore Microtubules: Spindle fibers that attach to kinetochores on chromosomes and pull them apart during cell division.