Metaphase I: During metaphase I, the spindle apparatus forms from opposite ends of the cell. The spindle apparatus then sends out spindle fibers to attach to the chromosomes. However, since the homologous chromosomes are lined up side by side for crossing over, they are tightly held together.
Why is it important that chromosomes line up during metaphase?
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. There is an important checkpoint in the middle of mitosis, called the metaphase checkpoint, during which the cell ensures that it is ready to divide.
Why do chromosomes need to align at the equatorial plate during metaphase?
The equatorial position of the metaphase plate ensures symmetric cell divisions.
What can happen if cells do not duplicate correctly?
The cell cycle controls the four major phases of cell growth and division. … If the cell has not properly copied its chromosomes, an enzyme called cyclin dependent kinase, or CDK, will not activate the cyclin, and the cell cycle will not proceed to the next phase. The cell will undergo cell death.
What 3 things happen in metaphase?
In metaphase, the mitotic spindle is fully developed, centrosomes are at opposite poles of the cell, and chromosomes are lined up at the metaphase plate.