1. Stem Cells

2. A life story..
Human development starts with just 1 cell – the fertilized egg
This cell divides to produce two identical daughter cells that divide again and again..

3. What are stem cells?
Stem cells are “rookie” cells that not yet “committed
Stem cells are undifferentiated cells (cells that are not specialized) that can become specialized (given a particular function)

4. Where can stem cells be found?
There are two types of stem cells: embryonic stem cells and adult stem cells
Embryonic stem cells are found in the blastocyst, a very early stage embryo
Adult stem cells are found in the tissues of the body (in a fetus, child, or adult)

5. How are stem cells different?
Stem cells are different from every body cell because they can both self-renew AND differentiate.
Self-renew: make copies of themselves
Differentiate: make other types of cells – specialized cells of the body (nerve cells, muscle cells, etc.)

6. Identical stem cells
Stem cell
SELF-RENEWAL
(copying)
Stem cell
Specialized cells
DIFFERENTIATION
(specializing)

7. Why is differentiation important?
Some specialized cells, like skin, red blood, and gut cells cannot undergo mitosis
Stem cells can divide, make copies of themselves, and then differentiate into the cells that need to be replaced.

8. Self-renew AND differentiate?
1 stem cell
4 specialized cells
1 stem cell
Differentiation - replaces dead or damaged
cells throughout your life
Self renewal - maintains the stem cell pool

9. all possible types of specialized cells
Embryonic stem cells
Embryonic stem cells are exciting because they can make all the different types of cell in the body
all possible types of specialized cells
differentiation
embryonic stem cells

10. Tissue stem cells
Tissue stem cells are more limited than embryonic stem cells because they can ONLY make the kinds of cell found in the tissue they belong to.
blood stem cell
differentiation
only specialized types of blood cell:
red blood cells, white blood cells, platelets
found in
bone marrow

11. Where do we find tissue stem cells?
surface of the eye
brain
skin
breast
intestines (gut)
testicles
bone marrow
muscles

12. Cloning
Reproductive cloning is when scientists remove the nucleus out of a normal cell from an organism and put it into the egg cell that had no nucleus.
This new cell is then forced to divide and develop into an embryo.
It is illegal to do on humans.

13. identical to the individual
remove nucleus
and take the
rest of the cell
egg
take the nucleus
(containing DNA)
cell from the body
Clone
identical to the individual
that gave the nucleus
Dolly the sheep