Stages of Mitosis

• Mitosis


  1. Prophase

  2. Metaphase

  3. Anaphase

  4. Telophase
• Mitosis


  The process of nuclear division by which two genetically identical daughter nuclei are produced that are also genetically identical to the parent cell nucleus (they have the same number of chromosomes as the parent cell)
• Mitosis is, in reality, one continuous process, but it can be divided into four main stages
• Chromosomes


  • Consist of two identical chromatids called sister chromatids (each containing one DNA molecule) that are joined together at the centromere
  • The different colours of the chromosomes are just to show that half are from the female parent and half from the male parent
• Prophase


  • Chromosomes condense and are now visible when stained
  • The two centrosomes (replicated in the G2 phase just before prophase) move towards opposite poles
  • Spindle fibres (protein microtubules) begin to emerge from the centrosomes
  • The nuclear envelope (nuclear membrane) breaks down into small vesicles
  • The nucleolus disappears
• Metaphase


  • Chromosomes line up at the equator of the spindle (also known as the metaphase plate) so they are equidistant to the two centrosome poles
  • Spindle fibres (protein microtubules) reach the chromosomes and attach to the centromeres
  • Each sister chromatid is attached to a spindle fibre originating from opposite poles
• Anaphase


  • The sister chromatids separate at the centromere (the centromere divides in two)
  • Spindle fibres (protein microtubules) begin to shorten
  • The separated sister chromatids (now called chromosomes) are pulled to opposite poles by the spindle fibres (protein microtubules)
• Telophase


  • Chromosomes arrive at opposite poles and begin to decondense
  • Nuclear envelopes (nuclear membranes) begin to reform around each set of chromosomes
  • The spindle fibres break down
  • New nucleoli form within each nucleus