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
CH 10 CELL GROWTH AND DIVISION
10.4 Cell Differentiation


All organisms start life as just one cell
Embryo
 Early
stage of development most multicellular
organisms pass through

Cells become more differentiated and specialized.
Differentiation

Process of cells becoming specialized.

Cell’s role can be determined at a specific point in
development.
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.
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
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
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.
Potential Benefits

Research may lead to new ways to repair the
cellular damage that results from heart attack,
stroke, and spinal cord injuries.
Ethical Issues


Most techniques for harvesting, or gathering,
embryonic stem cells cause destruction of the
embryo
Government funding vs. private funding.
Cellular Differentiation of
C. elangans

The adult microscopic worm C. elangans contains
959 cells. Copy the data table and then answer the
following questions.
1.
2.
3.
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