1 Review What happens during differentiation

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• 1 Review What happens during differentiation
• 2 Review What are stem cells
• Compare and Contrast How are embryonic stem
  cells and adult stem cells alike and how are they
  different
• 3 Form an Opinion How might technological
  advances help address the ethical concerns
  surrounding stem cell research

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Ch 10 Cell Growth and Division

• 10.4 Cell Differentiation

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• All organisms start life as just one cell
• Embryo
• Early stage of development most multicellular
  organisms pass through
• Cells become more differentiated and specialized.

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Differentiation

• Process of cells becoming specialized.

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• Cells role can be determined at a specific point
  in development.

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Differentiation in Mammals

• Controlled by a number of interacting factors in
  the embryo
• Chemical signals
• Regulatory factors
• Interaction between cells
• Adult cells generally can no longer differentiate.

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Stem Cells

• Unspecialized cells from which differentiated
  cells develop
• Totipotent
• Can form all the tissues of the body
• Only the fertilized egg and first few divisions

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Embryonic Stem Cells

• Pluripotent
• Capable of developing into many, but not all,
  cell types
• Located in inner mass of cells of blastocyst
• Blastocyst
• Early embryo stage with a hollow ball of cells
  with a cluster of cells inside

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Adult Stem Cells

• Multipotent
• Can produce many types of differentiated cells
• Typically produce only the types of cells that
  are unique to that tissue where they are located.

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Potential Benefits

• Research may lead to new ways to repair the
  cellular damage that results from heart attack,
  stroke, and spinal cord injuries.

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Ethical Issues

• Most techniques for harvesting, or gathering,
  embryonic stem cells cause destruction of the
  embryo
• Government funding vs. private funding.

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Cellular Differentiation of C. elangans

• The adult microscopic worm C. elangans contains
  959 cells. Copy the data table and then answer
  the following questions.

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1. Calculate Calculate the percentage of the total
   cell number reprented by each tissue or organ
   listed including other.
2. Infer Why does C. elanans make an ideal model for
   studying cellular differentiation
3. Infer Why would it be more difficult to map the
   differentiation patterns in a different organisms
   like a mammal