1. 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

2. Ch 10 Cell Growth and Division
10.4 Cell Differentiation

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

4. Differentiation
Process of cells becoming specialized.

5. Cell’s role can be determined at a specific point in development.

6. 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.

7. 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

8. Embryonic Stem Cells Pluripotent Blastocyst
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

10. 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.

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

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

13. Cellular Differentiation of C. elangans
The adult microscopic worm C. elangans contains 959 cells. Copy the data table and then answer the following questions.

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