HW: The Great Stem Cell Debate reading and questions Tuesday March 11, 2017 I can: explain how different cell types arise Agenda (10) Catalyst (5) Preview: Stem Cells (15) GN: Differentiation (15) IP: Differentiation (35) Stem Cells Readings & Questions (5) Exit Ticket Catalyst Where does your DNA come from? Do the cells in your body contain the same DNA? If they contain the same DNA, how do we have different types of cells? HW: The Great Stem Cell Debate reading and questions (IP if incomplete!)
Turned in STEM Survey DUE WEDNESDAY the 12TH Turned in STEM Survey DUE WEDNESDAY the 12TH! (100% = party Thursday, 13th!)
Exit Ticket Review 1. Which is an example of the relationship between environmental factors and gene expression? A. The offspring of a black hen and a white rooster are black and white due to co-dominance. B. A man is colorblind because he inherited the sex-linked trait for colorblindness from his mother. C. Two plants with the same genetic makeup have different flower colors due to the pH of the soil. D. The offspring of a red-flowered plant and a white-flowered plant have pink flowers due to incomplete dominance.
Exit Ticket Review 2. Which condition is linked to excess exposure to UV radiation? A. PKU B. diabetes C. skin cancer D. heart disease
Exit Ticket Review 3. Which of these traits is most influenced by environment? A. weight B. hair color C. blood type D. handedness
However, every cell in an organism contains the same DNA. There are around 200 specialized cell types in the human body, each type with a specific function. How is this possible? However, every cell in an organism contains the same DNA.
Not all genes are turned on at one time. Gene Expression Not all genes are turned on at one time. Different cell types have different parts of their DNA expressed, or turned on. Nerve cells only have the “nerve genes” expressed at any time. The “nerve genes” are transcribed into mRNA, and translated into “nerve proteins.” Muscle cells only have the “muscle genes” expressed at any time. The “muscle genes” are transcribed into mRNA, and translated into “muscle proteins.”
Because different genes are expressed in different cell types, different proteins are made and cells become specialized. The process of cells specializing is called differentiation.
Each of the specialized cell types found in our bodies developed from the same fertilized egg. How is this possible?
Stem cells are cells that have not yet differentiated. By expressing different genes, stem cells can become many other types of cells. Two types: embryonic stem cells; hematopoietic (adult) stem cells
Embryonic stem cells come from fertilized eggs that have developed for ~5 days. can turn into ANY type of cell. Adult (hematopoietic) stem cells are found in your bone marrow. constantly renew your blood cells.
Scientists have learned how to direct adult stem cells to turn into any cell type. Possible applications: growing organs in the laboratory to replace damaged ones growing new skin for a burn victim replacing defective insulin-producing cells in patients with diabetes