Stem Cells

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Stem Cells
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Remarkable Regeneration!
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Can humans regenerate body parts?
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Can humans regenerate body parts?
Think Pair Share If humans have stem cells
but cant grow back certain body parts, but a
lizard can grow back an entire tail, what must be
different between our stem cells and a lizards?
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Stem Cells

• Some stem cells are different than others!
• Stem cells vary in what they can become. Some
  stem cells can only become one type of cell,
  other stem cells can generate an entire organism!

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Stem Cells

• Potency
• Totipotent
• Pluripotent
• Multipotent
• Unipotent

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Stem Cells

• Potency
• Totipotent
• Pluripotent
• Multipotent
• Unipotent

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Stem Cells

• Potency
• Totipotent a stem cell that has the ability to
  divide and produce all the differentiated cells
  in an organism, including the placenta. A
  totipotent stem cell can generate an ENTIRE
  organism!
• Example cell from morula stage of embryo

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Stem Cells

• Potency
• Totipotent
• Pluripotent
• Multipotent
• Unipotent

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Stem Cells

• Potency
• Pluripotent a stem cell that has the ability to
  divide and differentiate into any fetal or adult
  cell type (but not the placenta). Thus, a
  pluripotent stem cell can differentiate into any
  cell type but cannot become a new organism.
• Example cell from inner cell mass of blastocyst

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Stem Cells

• Potency
• Totipotent
• Pluripotent
• Multipotent
• Unipotent

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Stem Cells

• Potency
• Multipotent a stem cell that has the ability to
  divide and differentiate into cells of a limited
  range of types.
• Example Blood stem cell (hematopoietic cell)

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Stem Cells

• Potency
• Totipotent
• Pluripotent
• Multipotent
• Unipotent

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Stem Cells

• Potency
• Unipotent a stem cell that has the ability to
  divide and differentiate into only one type of
  cell.
• Example Skin stem cells

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Stem Cells

• So, what IS a stem cell?

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Stem Cells
Think Pair Share Think back to the
definitions of potency we just discussed. What
two characteristics do all stem cells have in
common?
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Stem Cells

• So, what IS a stem cell?
• Two defining characteristics
• Self-renewal Retain the capacity to go through
  many cycles of cell division while remaining
  undifferentiated.
• Potency Ability to differentiate

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Stem Cells

• So, what IS a stem cell?
• A stem cell is a cell that has the ability to
  self-renew and differentiate along different
  pathways.

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Embryonic stem cells vs. Adult Stem cells
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Embryonic stem cells vs. Adult Stem cells

• Embryonic stem cell stem cell derived from the
  inner cell mass of an embryo.
• Are pluripotent

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Where do embryonic stem cells come from???
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Embryonic stem cells vs. Adult Stem cells

• Adult stem cell an undifferentiated cell taken
  from a tissue of the body that has the ability to
  divide and differentiate into specialized cell
  types.

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Where do adult stem cells come from?

• Usually there is a very small number of stem
  cells in each tissue of body
• Once removed, limited capacity to divide
• Scientists trying to find better ways to grow
  large quantities of adult stem cells.