Stages of Mitosis

• Mitosis is a type of cell division in which the nucleus of the cell divides into two nuclei with identical genetic material
• The resulting two daughter cells have the same number of chromosomes similar to the parent cell
• A diploid parent cell containing two sets of chromosomes (paternal - father, and maternal - mother chromosome sets) results in two diploid daughter cells after mitosis
• Mitosis occurs only in eukaryotes
• Mitosis is used by multicellular organism for

  • growth and development
  • repair of tissues
  • asexual reproduction
• Mitosis is a continuous process divided into 4 stages:

  1. Prophase
  2. Metaphase
  3. Anaphase
  4. Telophase
• Stage 1: Prophase

  • chromatids during interphase start to coil and become visible
  • each chromosome at this stage contains two sister chromatids (from DNA replication)
  • nuclear membrane dissolves
  • spindle fibers are formed
  • centrioles migrate to opposite poles
  • nucleolus disappears from the view
• Stage 2: Metaphase (M for Middle)

  • chromosomes move and align themselves at the center of the cell called metaphase plate
  • spindle fibers connect each chromosome in the kinetochore to the centrioles located at opposite poles
• Stage 3: Anaphase (A for Away)

  • the proteins that bind the two sister chromatids of each chromosome divide
  • movement of separated chromosomes toward opposite poles due to shortening of spindle fibers
• Stage 4: Telophase

  • separated chromosomes called chromatids are located on opposite poles
  • nuclear membrane forms around the chromosomes, which starts to uncoil
  • spindle fibers dissolve and disappear.
  • each chromosome in the resulting daughter cells is composed of only one chromatid
• prophase

  
• metaphase

  
• anaphase

  
• telophase

  
• interphase

  
• interphase

  
• prophase

  
• metaphase

  
• anaphase

  
• telophase

  
• After the division of the nucleus (karyokinesis), the cytoplasm starts to divide (cytokinesis).
• Cytokinesis in animal cells and other cells without cell walls start at the exterior of the cell and moves inward until the cell is divided into two cells. This process is called cleavage furrow formation
• In plant cells and other cells with cell wall, cytokinesis starts at the middle of the cell and moves outward through a process called cell plate formation