Prophase of cell mitosis. Image 2 of 6. Light micrograph of a bluebell cell (Endymion sp.) undergoing cell division (mitosis). A cell in an early stage of mitosis, known as prophase, is seen here. Individual chromosomes can be seen within the cell as orange thread like structures. During prophase, the chromosomes become progressively shorter and fatter and a tubular structure known as the spindle forms across the cell (not visible here). The spindle will later help each chromosome to split and separate, forming two daughter" nuclei at either end of the cell. Part of mitosis sequence, images B215/045 to B215/050."