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Cell Differentiation & Gene Expression

Cell Differentiation & Gene Expression. Introducing stem cells. A life story…. Stem cells cells that can differentiate into a variety of specialized cell types. What is a stem cell?. stem cell. SELF-RENEWAL (copying). DIFFERENTIATION (specializing). specialized cell

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Cell Differentiation & Gene Expression

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  1. Cell Differentiation&Gene Expression

  2. Introducing stem cells

  3. A life story… Stem cells cells that can differentiate into a variety of specialized cell types

  4. What is a stem cell? stem cell SELF-RENEWAL (copying) DIFFERENTIATION (specializing) specialized cell e.g. muscle cell, nerve cell stem cell

  5. What is a stem cell? Stem cell Stem cell DIFFERENTIATION (specializing) SELF-RENEWAL (copying) Identical stem cells Specialized cells

  6. Why 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

  7. Where are stem cells found? tissue stem cells fetus, baby and throughout life embryonic stem cells blastocyst - a very early embryo • Types of stem cells: • Embryonic stem cells • Tissue stem cells

  8. Embryonic stem (ES) cells: Where we find them blastocyst cells inside = ‘inner cell mass’ fluid with nutrients culture in the lab to grow more cells embryonic stem cells taken from the inner cell mass outer layer of cells = ‘trophectoderm’

  9. Stem cell jargon PotencyA measure of how many types of specialized cells a stem cell can make. PluripotentCan make all types of specialized cells in the body Embryonic stem cells are pluripotent. MultipotentCan make multiple types of specialized cells, but not all types Tissue stem cells are multipotent.

  10. Embryonic stem (ES) cells: What they can do differentiation embryonic stem cells PLURIPOTENT Embryonic stem cells are exciting because they can make all the different types of cell in the body – scientists say these cells are pluripotent. all possible types of specialized cells

  11. Embryonic stem (ES) cells: Challenges skin grow under conditions A grow under conditions B neurons embryonic stem cells grow under conditions C blood grow under conditions D ? liver

  12. Tissue stem cells: Where we find them surface of the eye brain skin breast intestines (gut) testicles bone marrow muscles

  13. Tissue stem cells: What they can do blood stem cell differentiation found in bone marrow only specialized types of blood cell: red blood cells, white blood cells, platelets MULTIPOTENT Tissue stem cells can ONLY make the kinds of cell found in the tissue they belong to. So, blood stem cells can only make the different kinds of cell found in the blood. Brain stem cells can only make different types of brain cell. Muscle stem cells can only make muscle cells. And so forth.

  14. http://www.youtube.com/watch?v=2-3J6JGN-_Y#t=36 A Stem Cell Story

  15. Cell Differentiation Cell differentiation – process of converting stem cells into more specialized cell types in multicellular organisms • Examples: muscle cells, liver cell, red blood cells

  16. When does cell differentiation occur? • Development of a zygote into a full • organism • Tissue repair • Normal cell turnover • All of these require the repeated division and differentiation of stem cells. Cell Differentiation

  17. What is gene expression? Gene expression is the activation of a gene that results in a protein & is a very controlled regulated process.

  18. Why are all our cells different? • They EXPRESS different portions of the genetic code (genes). • This means that different proteins are made by different cells causing them to look and function differently.

  19. How does Gene Expression make our body cells different? • Every cell in our body has the same 30,000 genes, but each cell selectively activates (“turns on”) certain genes

  20. The information on DNA (activated genes – those that are “turned on”) is translated into an organism's traits by producing specific proteins. How do you think a gene expresses itself? Protein

  21. Environmental factors such as temperature, pH, and availability of nutrients can influence the genes expressed in a cell. Genes + Environment = Trait Why are twins “not exactly” alike?

  22. Himalayan Rabbits • If a small section of fur is shaved from a Himalayan Rabbit, the fur will grow back either white or black depending on the temperature of its environment . COLD HOT

  23. Hydrangea • How does the environment affect hydrangea growth? • Depending on the pH of the soil, Hydrangea can range in color from blue to pink.

  24. All the cells in our body have the exact same DNA because they all came from a single cell which replicated its DNA Although every cell in your body has the same DNA, not all cells are the SAME. Why? Gene Expression

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