During prophase,
the chromatin condenses and the chromosomes become visible. Also the nucleolus
disappears, the nuclear membrane fragments, and the spindle appartus forms
and attaches to the centromeres of the chromosomes. These are dividing cells
in the roor tip of an onion plant. Early prophase can be seen. The
chromatin is condensing into chromosomes, the nucleolus is still visible,
and the nuclear envelope has not yet fragmented.
