5. The two brothers represent 2 out of more than 10 14 (100 000 000 000 000) possible children that a couple could conceive They are genetically programmed to be different
Main Idea(s) of This Slide - Because there are 10 14 possible combinations of chromosomes in the combinations of different sperm and eggs from one couple, the chances of having two that are identical are virtually zero.
Main Idea(s) of This Slide - Dr. James Thomson, from the University of Wisconsin, was the first to cultivate stem cells. He collected stem cells from surplus embryos from fertility clinics. He stopped the cells from differentiating, but kept them dividing producing large quantities of undifferentiated cells.
Main Idea(s) of This Slide - Fertilization of the ovum by the sperm occurs in the oviduct. This is where the diploid number is restored (2n) in the zygote. The zygote then undergoes mitotic division which increases it’s number of cells, but no differentiation is occurring. Eventually a blastocyst stage is reached. The blastocyst is characterized by a hollow interior with an inner cell mass. The inner cell mass is where embryonic stem cells are located. The cells of the inner cell mass have the potential to differentiate into any of the 210 tissue types of the adult body. The blastocyst stage is the stage of development where implantation into the endometrium occurs.
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