Mitosis Notes

Mitosis occurs in a series of stages, or phases.

1st: INTERPHASE

• Chromosomes are copied (# doubles)
• Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy
  (sister chromosome) change to sister chromatids at end of this phase

 2nd: PROPHASE

• Mitosis begins (cell begins to divide)
• Centrioles (or poles) appear and begin to move to opposite ends of cell
• Spindle fibers form between the poles

 3rd: METAPHASE

•  Chromatids (or pairs of chromosomes) attach to the spindle fibers

4th: ANAPHASE

•  Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell

 5th: TELOPHASE

• Two new nuclei form
• Chromosomes appear as chromatin (threads rather than rods)
• Mitosis ends

6th: CYTOKINESIS

• Cell membrane moves inward to create two daughter cells - each with its own nucleus with identical chromosomes