Mitosis

• Nucleus

  • control cell activities
  • copied from cell to cell when cells divide
  • passed into new individuals when sex cells fuse together during sexual reproduction

  Nuclear envelope

  • separates the contents of the nucleus from the rest of the cytoplasm
• Prophase

  • Chromatin condenses by supercoiling to become 2 sister chromatids held together at the centromere
  • Nucleolus gradually disappears
  • Nuclear envelope breaks down
• Metaphase

  • Two centrosome move to opposite ends of the cell
  • Microtubules from the cytoplasm form into a spindle radiating out from the centrosome
  • Each pair of sister chromatids is attached to a microtubule of the spindle and arranged at the equator of the spindle
• Anaphase

  • Centromeres separate
  • Spindle fibres shorten
  • Sister chromatids pulled to opposite poles
  • Once separated, they are called chromosomes
• Telophase

  • Nuclear envelope reforms around both groups of chromosomes at opposite ends of the cell
  • Chromosomes decondense, uncoil becoming chromatin
  • Nucleolus reforms