Mitosis                                                                              Faris Al-Ahmadi

                                                                          18th October, 2010

Data Collection

Table with 100 cells recorded in an onion root tip to show which stage of mitosis each cell is in

Table with 100 cells recorded in a different onion root tip region to show which stage of mitosis each cell is in

*These uncertainties are an estimated non-systematic (human) error during the practical.  

Data Processing



                                                 = ± 5 Cell Error Margin


  1. Describe the events occurring in each stage of mitosis emphasizing the movement of chromosomes.

Prophase: This phase is the first phase in mitosis. In prophase, chromatids formed from interphase are starting to be shown as chromosomes, since they are shortening and thickening, making them more visible to a microscope. Each chromosome contains two sister chromatids, joined together by a centromere. The nuclear membrane of the nucleus starts to disappear, and so does the nucleolus. Centrioles in the cell start to move to either end of the cell, and they stay put at the ends. The centrioles start to produce mitotic spindles, which are extending across the cell.

Metaphase: The nuclear membrane is fully disappeared, and the mitotic spindles are rapidly extending across the cell. The spindles are then attached to the kinetochore of each chromosome, and the spindles align the chromosomes in the middle of the cell. They are aligned in the middle so that when separated in anaphase, the nucleus from the two daughter cells will get a copy from each chromosome.

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Anaphase: The chromosomes separate from the kinetochore, and so one chromatin from the chromosome goes to one side, and the other chromatin gets pulled to the other side. These chromatids are then known as chromosomes when separate. In anaphase, the chromatids are not at the sides yet, but rather just separated and heading towards the sides.

 Telophase: The chromatids have reached each side of the cell, and then the whole cell starts to split. During this phase, the copy chromatids on either side are then wrapped in a new ...

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