Most of a cell’s DNA is not translated Flashcards
What are stem cells?
Undifferentiated cells that can continuously divide and become specialized through differentiation.
What are the different types of stem cells?
Totipotent, pluripotent, multipotent and unipotent stem cells
Describe totipotent stem cells
Stem cells that can divide and produce any type of body cell. During development they translate only part of their DNA resulting in cell specialisation. The only occur for a limited time in mammalian embryos.
Describe pluripotent stem cells
They are stem cells that are found in embryos and can become almost any type of cell but not placental cells. These cells are used the most in stem cell research but there are many ethical issues such as destruction of embryos and the continual division which can result in tumours.
Describe multipotent stem cells
They can only differentiate into a limited number of cells. They are found in adult bone marrow, placenta and umbilical chords. In bone marrow they can only differentiate into blood cells.
Describe unipotent stem cells
They can only differentiate into a single type of cell. They are found in adult organ tissues e.g in the skin unipotent stem cells can only differentiate into skin cells.
Describe induced pluripotent stem cells
They are multipotent or unipotent stem cells taken from somatic cell of a consenting adult and are manipulated using transcriptional factors. All the genes are turned on bringing back pluripotency. They are better to use in research because they divide indefinetly so only one sample is needed from one patient. They also do not destroy embryos as they are from a consenting adult.
