What is the difference between embryonic and adult stem cells? Are those the only two types?
Stem cells are generally classified into adult and embryonic stem cells. Adult stem cells are found throughout the human body, in different places. Embryonic stem cells usually come from embryos, from fetus cells. Those embryonic cells can remain undifferentiated for years, if properly frozen. They can replicate and multiply while remaining undifferentiated, they can maintain their genotype and teleomerase. With adult stem cells, for example the types that we get from bone marrow, they can only go through four replications. Question 5: How does one harvest stem cells? For the bone marrow, it is pretty easy. We simply aspirate bone marrow from the Illiac crest. We then take the bone marrow and process it, and select for the cells that adhere to plastic. Usually blood cells will not stick, and eventually die. But people have different techniques for isolating stem cells. Everybody has their own tricks for isolating the purest population of stem cells. Question 6: What proportions of your
