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Stem cells

Stem cells. Objectives Understand the difference between a totipotent, a multipotent and a pluripotent. Analyse the ethics of treatment by stem cells. . Salamander video. To start…lets think about genes. .

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Stem cells

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  1. Stem cells Objectives • Understand the difference between a totipotent, a multipotent and a pluripotent. • Analyse the ethics of treatment by stem cells.

  2. Salamander video

  3. To start…lets think about genes. All body cells contain the same genes. However, not all the genes in a cell are expressed. Can you name….. A gene that is expressed in every body cell? E.g. enzymes for respiration-all cells respire A gene that is only expressed in one type of body cell? E.g. Insulin. It is only produced in the pancreas.

  4. Differentiation Genes that are not needed in a cell are switched off (permanently) This is how cells become specialised. Name a specialised cell (any) and state an adaptation that it has.

  5. Totipotent. All genes are switched on. The cell can become anything. Zygote up until the 16 cell stage in humans. Pluripotent. Embryonic stem cells. Can develop into most tissue types. Only some genes switched off. Multipotent. Can develop into only a limited number of cell types. E.g. bone marrow-can form any part of the blood.

  6. Stem cells Embryonic stem cells = totipotent/plutipotent Adult stem cells = multipotent Medical uses Stem cells are at their full potential when they are your own. Why is it important that they are your own and why is this problematic. How would you obtain embryonic stem cells and how would you make sure that they are your own.

  7. Embryonic stem cells • Embryonic stem cells have the greatest potential for treating disease as totipotent/pluripotent • Can be grown in vitro • Differentiation / specialisation can be directed using chemicals • Possible Uses: skin grafts for serious burns; nervous tissue for Parkinson’s; heart muscle cells after M.I. • Only allowed under licence • Only if to be used for medical purposes • Only if the embryo is grown in vitro.

  8. Ethics of embryonic stem cells.

  9. Difference between totipotent and pluripotent stem cells. Totipotent = fully unspecialised, all genes on, can become any kind of cell, up to 16 cell stage Pluripotent = Partially specialised, can become a small number of cells types, but still more unspecialised than multipotent. Adult stem cells. Multipotent. Can only form a few cell types e.g. bone marrow can form any part of the blood. Not many medical uses. Medical use of stem cells Need to be embryonic. Need to be from you as these do not trigger an immune response. Taken from embro’s that are clones and developed in vitro. Can be used to replace damaged tissue. Reasons for and against using embryonic stem cells. Destroy foetus-could develop into a real person. Can treat life threatening disease A lot of money could be made Need to be clones.

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