what happens during metaphase of mitosis

During metaphase of mitosis, the cells chromosomes align themselves in the middle of the cell through a type of cellular "tug of war". Prior to metaphase, protein formations called kinetochores formed around the centromere. Long protein filaments called kinetochore microtubules extended from poles on either end of the cell and attached to the kinetochores. During metaphase, the kinetochore microtubules pull the sister chromatids back and forth until they align along the equator of the cell, called the equatorial plane. At this stage, the chromosomes are distinguishable when viewed through a microscope and are used in karyotyping, a laboratory technique for identifying chromosomal abnormalities. There is an important checkpoint in the middle of mitosis, called the metaphase checkpoint, during which the cell ensures that all of the chromosomes are properly aligned and that the kinetochores are correctly attached before entering the next phase of mitosis, known as anaphase.