Stages of Mitosis: Prophase

Onion cell in prophase. © The Entangled Bank

Mitosis, a process of cell division, enables organisms to grow and reproduce. Dividing cells go through an ordered series of events called the cell cycle.

In the stage of mitosis called prophase, changes occur in both the cytoplasm and nucleus of the dividing cell. The chromatin condenses into discrete chromosomes. The chromosomes begin to migrate toward the cell center. The nuclear envelope breaks down and spindles form at opposite poles of the cell.

In animal cells, the mitotic spindle initially appears as structures called asters which surround each centriole pair.

Learn more about mitosis:

• Mitosis Image Gallery
  
• Mitosis Study Guide
  
• Mitosis Quiz