1. 1.1 Introduction to cells Multicellular Organisms

2. Learning objectives U: Multicellular organisms have properties that emerge from the interaction of their cellular components U: Specialised tissues can develop by cell differentiation in multicellular organisms U: Differentiation involves the expression of some genes and not others in a cell’s genome U: The capacity of stem cells to divide and differentiate along different pathways is necessary in embryonic development and also makes stem cells suitable for therapeutic use A: Use of stem cells to treat Stargardts disease and one other named condition A: Ethics of therapeutic use of stem cells from specially created embryos, from the umbilical cord blood of new-born baby and from an adult’s own tissues

3. Multicellular organisms When cells are grouped together, they exhibit emergent properties, as a result of interactions between cellular components, that are not present when cells are on their own VS http://www.ector- county.k12.tx.us/cms/lib/tx01000975/centricity/Domain/3889/orchestra.gif What are some examples of emergent properties when you compare organs/tissues with cells?

4. What is a stem cell?

5. Stem cells retain the capacity to divide and have the ability to differentiate along different pathways http://www.chxa.com/img/stem-cells-hierarchy.jpg

6. What happens during differentiation? If every cell has the same DNA, why can cells look and behave differently?! (stem cell) All the genes are expressed Not all genes expressed Gene expressed Gene not expressed

7. Where do stem cells come form? 1. Embryonic development 2. Umbilical cord blood http://cord-blood-bank.weebly.com/uploads/5/4/9/6/549610/umbilical_cord_blood.jpg 3. Adult tissue http://stemcells.nih.gov/StaticResources/info/s cireport/images/figure42.jpg

8. Red blood cells White blood cells Lymphocytes, Phagocytes Platelets Why are stem cells suitable for therapeutic purposes?

9. Examples of therapeutic stem cell use: 1. Stargardt’s macular dystrophy http://www.stmichaelseye.com/wp- content/uploads/2013/08/stargardts_disease.jpg Recessive mutation in ABCA4 gene Photoreceptive cells degenerate progressively (macular degeneration) Embryonic stem cells injected into retina. There was improvement and no harm in patient

10. Examples of therapeutic stem cell use: 2. Leukemia Cancer which overproduces WBCs in bone marrow Normal WBC = 4-11,000/mm 3 Leukemia WBC = <30,000- 100,000/mm 3 Adult stem cells are extracted from bone and injected into patient that is treated with drugs until their bone marrow no longer produces blood cells. http://www.drhasmah.com/wp- content/uploads/2013/09/bone-marrow.jpg

11. What are some ethical issues that may arise from the therapeutic use of stem cells? In favour of stem cell therapyAgainst stem cell therapy