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    How do embryonic stem cells become specialised? I know you have to switch certain genes on but how? What is the specialising process called?

    It says embryonic stem cells are taken from unused embryos? But what does it mean by unused embryos because how can there be unused embryos, dont they all develop into a fetus?

    What is a embryo?
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    (Original post by Daydreamer3)
    How do embryonic stem cells become specialised? I know you have to switch certain genes on but how? What is the specialising process called?

    It says embryonic stem cells are taken from unused embryos? But what does it mean by unused embryos because how can there be unused embryos, dont they all develop into a fetus?

    What is a embryo?
    The process by which cells become specialised is called differentiation.

    When an egg is fertilised, if forms a zygote. The zygote will then divide continuously, by mitosis. Once it reaches eight cells it is called an embryo, and all of the cells are identical. It is these embryonic stem cells which can be differentiated for different uses.
    An unused embryo just refers to an embryo that is not being used for pregnancy.
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    (Original post by lizzieerobinson)
    The process by which cells become specialised is called differentiation.

    When an egg is fertilised, if forms a zygote. The zygote will then divide continuously, by mitosis. Once it reaches eight cells it is called an embryo, and all of the cells are identical. It is these embryonic stem cells which can be differentiated for different uses.
    An unused embryo just refers to an embryo that is not being used for pregnancy.
    But what is involved in this differentiation process, how does exactly the embryonic stem cells become specialised? So what happens to make them specialised?

    How many embryos are there in a pregnancy because how cant it be used if there is only one?
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    I'm afraid this goes a bit beyond my knowledge, however I believe there are certain conditions under which stem cells become differentiated into specific specialised cells.

    There is only one embryo during pregnancy as of course only one egg is released from the ova. However, in processes such as IVF in which multiple eggs are being fertilised with multiple sperm cells there are left over, or unused embryos.
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    (Original post by Daydreamer3)
    But what is involved in this differentiation process, how does exactly the embryonic stem cells become specialised? So what happens to make them specialised?

    How many embryos are there in a pregnancy because how cant it be used if there is only one?
    The embryonic stem cells can become specialised by gene expression changes (turning genes on and off). Gene expression is pretty complex, but some of the ways genes can be switched on and off are methylation (adding methyl groups to the nucleotides) and transcription factors (molecules which increase/decrease the rate of gene transcription). Methylation is at the epigenetic level (directly affects DNA itself without affecting the sequence), transcription factors affect transcription machinery (affect the molecules that make RNA using DNA as a template).

    The embryos usually come from IVF, where more embryos than are required may be made, so instead of simply being disposed of, they can be used for research.
 
 
 
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