Mitosis

• Mitosis

  A process whereby one cell (mother cell) gives rise to two cells (daughter cells) with the identical genetic make-up as the original (mother) cell
• DNA replication

  1. An identical copy of the DNA material is made just before the cell starts to divide

  2. Each chromosome appears as two chromatids, which are held together by a centromere
• Mitosis

  • Takes place in the body cells (somatic cells) of both plants and animals
• Cell cycle

  1. A series of phases through which a cell progresses when it is actively dividing

  2. Interphase (normal cell activity)

  3. Mitosis (4 phases: prophase, metaphase, anaphase, telophase)
• The cell cycle can be condensed to a 24-hour period
• Chromosome


  • In its single state
  • In its double state (after DNA replication)
• Mitosis in an animal cell


  1. Prophase (chromatin condenses, spindle fibers form)

  2. Metaphase (chromosomes move to equator, attached to spindle)

  3. Anaphase (chromosomes separate, move to poles)

  4. Telophase (nuclear membrane reforms, cell divides)
• Cell plate


  Forms between the two nuclei in plant cells during telophase, becomes the new cell wall
• Cytoplasmic cleavage


  In animal cells, a furrow forms at the equator and deepens to divide the cytoplasm in two, each with its own nucleus
• Cancer

  • Cells divide by mitosis in an uncontrolled manner, resulting in abnormal cell numbers and a tumour
  • Tumour may be benign (contained) or malignant (spread to other areas)
  • Substances that cause cancer are called carcinogens
• Traditional African medicines have been used to relieve side effects of chemotherapy and radiation treatments