The cell is in Interphase for most of its life cycle. In Interphase, the cell “prepares” for division by obtaining nutrients and growing, copying its DNA, and replicating its centrioles. The nuclear membrane is still visible.
Chromatin has not yet condensed into chromosomes in this stage.
In Prophase, DNA chromatin condense into easily visible chromosomes. The chromosomes are held together by centromeres. The two strands of chromosome are called sister chromatids.
The nuclear membrane and nucleolus disappear.
The centrioles move to opposite ends of the cell.
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Spindle fibres from the centrioles attach to the centromeres of the chromosomes
Chromosomes align at the middle of the cell. This organization helps to ensure that in the next phase, when the chromosomes are separated, each new nucleus will receive only one copy of each chromosome.
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In anaphase, the spindle fibres shorten, which splits the chromosome strand into two separate, sister chromatids. The sister chromatids are pulled to opposite ends of the cell.
This is the only stage in the life of a cell where the chromosome number is greater than a 2n (or diploid) count.
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The chromosomes finally reach opposite poles (the ends) of the cell.
The nuclear envelope and nucleolus reform around each new set of chromosomes. The chromosomes disperse and are no longer visible.
Spindle fibres disperse and are no longer visible.
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Citokinesis marks the end of mitosis in the cell cycle. It is where the cell officially splits into two separate cells, called daughter cells. Each daughter cell now has the same number of chromosomes as the original cell before mitosis. The cell splits when a furrow forms that pinches the cell in two.
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Video of Prophase Click the image above to see a histological video of Prophase Return to previous slide Quit
Video of Metaphase Click the image above to see a histological video of Metaphase Return to previous slide Quit
Video of Anaphase Click the image above to see a histological video of Anaphase Return to previous slide Quit
Video of Telophase Click the image above to see a histological video of Telophase Return to previous slide Quit
Kevin Annis is a junior at Grand Valley State University. He is majoring in biology and is pursuing a minor in chemistry. Currently he is considering getting a second minor in psychology. He plans on teaching biology at the high school level when he completes college. He most enjoys the summer months, where he spends most any free time golfing or fishing.