Definition: Polar fibers are spindle fibers that extend from the two poles of a dividing cell.
They connect to the centromere region of chromosomes via kinetochore fibers in order to manipulate and separate the chromosomes during cell division.
They connect to the centromere region of chromosomes via kinetochore fibers in order to manipulate and separate the chromosomes during cell division.
Examples:
During metaphase of mitosis, polar fibers extend from the cell poles to align chromosomes at the metaphase plate. In anaphase, polar fibers connected to chromosomes shorten thereby separating sister chromatids and pulling them toward the spindle poles. Polar fibers not connected to chromosomes lengthen and elongate the cell.


