Mitosis

Mitosis

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Mitosis is when the Cell divides into 2 cells with 46 chromosomes in each of the cells. First, the cell goes through prophase which is when the nucleolus fades and the nucleolus fades and the chromatin condenses into chromosomes. Each replicated has 2 chromatids, both with the same genetic information. Microtubules of the cytoskeleton, responsible for cell shape, mobility and attachment to other cells during interphase disassemble. And the building blocks of these microtubules are used to grow the mitotic spindle from the region of the centrosomes.

Next is prometaphase. In this stage, the nuclear envelope breaks down so there is no longer a recognizable nucleus. Some mitotic spindle fibers elongate from the centrosomes and attach to kinetochores, protein bundles at the centromere region on the chromosomes where sister chromotids are joined. Other spindle fibers elongate but instead of attaching to chromosomes, overlap each other at the cell center.

The stage after Prometaphase is Metaphase. Metaphase is the tension applied by the spindle fibers aligns all chromosomes in one plane at the center of the cell.

Next is anaphase. Anaphase is when the spindle fibers shorten, the kinetochores separate, and the chromatids are pulled apart and begin moving to the cell poles.

Telophase is when the daughter chromosomes arrive at the poles and the spindle fibers that have pulled them apart disappear.

Cytokinesis is the last stage before starting at interphase again. Cytokinesis is when the spindle fibers not attaché to chromosomes begin breaking down until only that portion of overlap is left. It is in this region that a contractile ring cleaves the cell into two daughter cells. Microtubules then reorganize into a new cytoskeleton for the return to interphase.

Mitosis is important because it makes new cells so we can constantly have new cells as the old cells die.

During mitosis, the chromosomes are copied into the new cells and repackaged. During Prophase the chromosomes condense. During Metaphase, the chromosomes line up the middle of the cell. During Anaphase, the chromosomes split in the middle. During telophase, the chromosomes are divided into 2 portions.