Prophase
Prophase

Prophase

At prophase the replicated chromosomes condense. Compare the staining of the chromosomes in the prophase cell to those in the surrounding, non-dividing cells. Each chromosome in prophase consists of two sister chromatids. Note that the nuclear envelope is still intact. In the cytoplasm, the mitotic spindle assembles between the two centrosomes and the centrosomes begin to migrate to opposite sides of the cell.