In: Biology
Spindle fibers composed of protein which is polymer of alpha and beta tubulin which form "MICROTUBULE " and form a protein structure that divide the genetic material in a cell during cell division.
During mitosis the spindle fibers called mitotic spindle.
at the beginning of nuclear division, two wheel-shaped protein structures called centrioles position themselves at opposite ends of the cell forming cell poles. Long protein fibers called microtubules extend from the centrioles in all possible directions, forming what is called a spindle. Some of the microtubules attach the poles to the chromosomes by connecting to protein complexes called kinetochores. Kinetochores are protein formations that develop on each chromosome around the centromere, which is a region located near the middle of a chromosome. Other microtubules bind to the chromosome arms or extend to the opposite end of the cell. During the cell division phase called metaphase, the microtubules pull the chromosomes back and forth until they align in a plane along the equator of the cell, which is called the equatorial plane. The cell goes through an important checkpoint to ensure that all of the chromosomes are attached to the spindle and ready to be divided before it proceeds with division. Next, during anaphase, the chromosomes are simultaneously separated and pulled by the spindle to opposite poles of the cell.