Mitosis
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Now that everything is in place the cell can actually divide. Mitosis is divided into 4 separate phases, prophase, metaphase and anaphase.
Prophase
Prophase is the first phase in mitosis. During prophase the chromatin condenses, ie. it coils and packs together to form visible structures. The nucleoli disappear. The nuclear envelop dissolves. The centrioles divide and begin migrating around the cell until they reach opposite polls. Microtubules grow from the centrioles (asters) toward the chromosomes and attach to the chromatids at the centromere region.
The first image to the near right is a photograph of a model of an animal cell during prophase. The photomicrograph to the far right is of onion root tip. Notice how in prophase the chromatin is very granular to stringy in appearance. There are no nucleoli and there is no nuclear envelop present.
