Mitosis

• Mitosis (general)

  • nuclear division that occurs in somatic cells
  • maintains parental diploid number of chromosomes in daughter cells
  • needed for bodily growth and asexual reproduction
  • broken into 4 phases: prophase, metaphase, anaphase, telophase
  • for the completion of cell division, cytokinesis (separation of the cytoplasm) follows mitosis
  • 2 separate, identical, diploid daughter cells are produced
• Mitosis (metaphase)

  1. chromosomes move to the centre of the cell and line up on the equator
  2. centromeres are aligned on the equator
  3. centrioles/centromeres are located at opposite poles of the cell
• Mitosis (prophase)

  1. chromatin condenses
  2. nuclear membrane disintegrates
  3. spindle fibres attach to each chromosome at its centromere
  4. 2 chromosomes move toward opposite poles of the cell
• Mitosis (anaphase)

  1. spindle microtubules shorten and pull on the centromeres; sister chromatids seperate
  2. centromeres are pulled towards opposite poles
  3. at the end of each phase, each pole has a complete identical set of maternal and paternal chromosomes
  4. sister chromatids are now chromosomes
• Mitosis (telophase)

  1. chromosomes decondense to form chromatin
  2. 2 new nuclear membranes form
  3. nucleoli reappear and spindle apparatus disappears
  4. cell elongates
• Cytokinesis in Plant Cells

  • cytoplasm divides with the formation of a cell plate
  • cellulose is deposited at the cell plate, forming a wall that divides the parent cell into 2 daughter cells, each one with a cell membrane
• Cytokinesis in Animal Cells

  • cell membrane pinches together to form a cleavage furrow

  -this continues to develop until the cell membrane eventually meets at a point, and the cell is split, resulting in 2 new daughter cells