The first stage of mitosis is prophase.

Quick Scoop

  • In prophase, the chromosomes condense and become clearly visible under a microscope.
  • The nuclear envelope starts to break down, and the mitotic spindle (the structure that helps move chromosomes) begins to form.
  • Centrosomes move toward opposite sides (poles) of the cell, preparing to pull the duplicated chromosomes apart later.

In everyday terms, prophase is when the cell “gets organized” for division: the DNA that was loose during interphase coils up tightly into neat packages (chromosomes) so it can be separated accurately into two new cells.