Prophase
Chromosomes begin to condense, taking on the form
that they are usually depicted in: four arms
connected at a point. Each chromosome is, at this
time, actually two identical copies. Each copy is
called a chromatid.
A spindle begins to form from the centrioles. This
spindle is made of fibers. The centrioles begin to
separate.
Also, the membrane of the nucleus, or nuclear
envelope, fragments and disperses.
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Prophase I
The activities are the same as in mitosis, except
that in this cell the chromosomes attach to the
membrane of the nucleus and then pair up with their
corresponding chromosome.
While paired up, enzymes cut sequences of DNA
(genes) from the chromosomes. These sequences are
exchanged between the chromosomes, which allows for
an exchange of genes between the two.
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