Most of a cell's DNA is not translated

• Define stem cell

  Undifferentiated cells that can divide by mitosis an unlimited number of times
• What are the 4 types of stem cell?

  Totipotent

  Pluripotent

  Multipotent

  Unipotent
• Describe totipotent stem cells

  Can differentiate into all cell types.

  Found in a zygote
• Describe pluripotent stem cells

  Can differentiate into all cell types apart from placental cells

  Found in the embryo
• Describe multipotent stem cells

  Can differentiate into a limited number of cell types.

  Found in the placenta, umbilical cord and adult bone marrow
• Describe unipotent stem cells

  Can only differentiate into one cell type such as cardiomyocytes
• Describe induced pluripotent stem cells

  1. Differentiated cells are removed from a person
  2. Transcription factors are added which switch on genes for the cell to become undifferentiated again
  3. The stem cells are injected into a tissue, which can differentiate into that cell type