Introduction to Stem Cells 1

What is a stem cell? Master cell. Undifferentiated (unspecialised cell type). Found in all multicellular organisms. Self-renewing and can differentiate. Can you give examples of differentiated cells and their functions? 2

Embryonic stem cells Totipotent: toti = total potent = capacity The state of the cells after the first few divisions of the fertilised egg. Have the capacity to become all cell types plus placenta. 3

Embryonic stem cells Pluripotent: pluri = many potent = capacity At blastocyst stage cells become pluripotent. Have the capacity to become all cell types but not placenta. Cells of most interest to research scientists. 4

Adult stem cells Multipotent Can develop into cells that are closely related. Limited number of several cell types. Make all cell types from the tissue they come from. Found in many parts of the body. Can self-renew over a lifetime. Not clear on the differences between the 2/3/4 points 5

Focus questions What is the unique property of stem cells which makes them different from a specialised cell? 6

Focus questions What does it mean when we say a cell has become ‘differentiated’? 7

Focus questions Embryonic stem cells are described as pluripotent whereas adult stem cells are multipotent. Describe in your own words what these terms mean. 8

Focus questions Why does adult tissue need stem cells? 9

Focus questions Why are research scientists so interested in using stem cells? 10

Focus questions We have discussed several types of stem cells. Which type do you think would be most useful to treat human disease? Give a reason for your answer. 11

Focus questions Each group has to investigate a disease that could be treated with stem cells. For the disease the group has identified: describe the condition identify the organ/system affected give a reason for why stem cells rather than drug therapy would be beneficial. Does it make a difference to say ‘rather than’ in place of ‘and not’ ? I thought the ‘and not’ might imply drugs were useless? 12