Stem Cells

I am doing edexcel alevel so can someone pls tell me about how embryonic stem cells are formed?

Are you doing the new 2015 Edexcel spec? If you are, then I don't think we need to know exactly how they're formed. Just need to know the terms: stem cells, pluripotent, totipotent, multipotent, and differentiation.

I am doing IAL

Ok, I'm not sure I can help you completely as it might be different for you. Have you read the specification for Edexcel IAL Biology?

I am doing edexcel alevel so can someone pls tell me about how embryonic stem cells are formed?

You start with a fertilised zygote that is fully totipotent (can become any cell type). Then after several cell divisions it will develop into an embryo. The cell of the embryo are known as pluripotent (can become almost any cell type). Then as the embryo develops certain biological signals will cause different cells to adopt different cell fates until most cells have a determined cell fate (apart from adult stem cells).

So embryonic stem cells aren't really 'formed', they're just cells before the biological signals specify a cell fate for them. The only stem cells that can really be formed are the zygote (by fertilisation) and induced pluripotent stem cells (differentiated cells can be subjected to certain compounds that cause them to undifferentiate and become stem cell like, although there are problems with this!)

Hope this helps you!

(Second year Biology student)