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Totipotency & Cell Specialisation
Transcript of Totipotency & Cell Specialisation
Totipotent cells are unspecialised cells but develop and divide into new, specialised cells.
In humans they are only present in the early life of an embryo. After this point, the embryonic stem cells lose their totipotency and the few stem cells that remain become multipotent meaning they call only develop into a few types of cells.
Mature plants also have stem cells that are found in areas where the plant is growing.
All stem cells in plants are totipotent which means they can be used to grow plant organs or whole new plants in vitro. How do cells lose their totipotency and become specialised? Some stem cell therapies already exist for some diseases affecting the blood and the immune system.
Bone marrow contains stem cells that can become specialised to form any type of blood cell so bone marrow transplants can be used to replace the faulty bone marrow in patients that produce abnormal blood cells. The stem cells in the transplanted bone marrow divide and specialise to produce healthy blood cells. This technique has been used to successfully treat leukaemia and lymphoma. It has also been used to treat genetic diseases such a sickle-cell anaemia and severe combined immunodeficiency.
Scientists are currently researching the use of stem cells as treatment for lots of other conditions such as:
Spinal cord injuries
Heart disease and damaged caused by heart attacks
Organ transplants Stem cells become specialised because during their development they only transcribe and translate part of their DNA.
Under the right conditions, some genes are expressed and others are switched off and mRNA is only transcribed from specific genes. The mRNA from these genes is then translated into proteins.
The proteins modify the cell by determining the cell structure and controlling the cell processes.
The changes to the cells produced by these proteins cause the cell to become specialised. These changes are difficult to reverse so once a cell has specialised, it stays specialised.