Stem Cells and Differentiation

• What are stem cells?


  Stem cells are undifferentiated cells. There are many in a human embryo but only few in an adult human. Witththe correct hormonal and genetic signals they can have the ability to become any specialised cell in the body.
• What are the cells in the embryo?


  They are undifferentiated and all the same
• How is an embryo formed?


  After fertilisation the cells divide by mitosis to form an embryo
• What are the cells in a foetus (an unborn baby)?


  They are highly specialised and differentiated. These babies need different types of cells in order to use different functions. As the fertilised egg divides, the cells specialise forming parts of the babies body. The specialised cells undergo MITOSIS to grow further cells.
• What is the role of stem cells in a human body?


  Their role is to replace body cells that die through injury or disease. They only differentiate cells from the type of tissue where they are found.
• Why is it useful for stem cells to be in plants?


  Due to the high amount of stem cells in different parts of the plant, it is possible to make complete plants from a small part of the plant, or even just a few cells.
• What is differentiation?


  it is the process by which a cell changes to become specialised for a specific job
• Cells need to be differentiated to become specialised
• How does differentiation work in an animal cell?

  • most specialised cells can divide by mitosis but only form the same type of cell
  • however, some differentiated cells like (red blood cell and skin cells) cannot divide at all by mitosis so adult stem cells are need to replace dead or damaged cells.
  • nerve cells do not divide at all and cannot be replaced by stem cells so the damage is permanent
• How does differentiation work in a plant cell?

  • most plant cells are able to differentiate all throughout their lives
  • stem cells are formed at active regions of the stems + roots or at the meristem
  • in these regions mitosis takes place almost continuously.
  • the cells elongate and grow before they are finally differentiated once in their final positions
  • once differentiated they can redifferentiated and become a completely different type of cell
• What is tatipotent?

  Stem cells which can turn into any other type of cell
• What is multipotent?


  Stem cells which can only turn into set types of cells
• How can we use stem cells in humans?


  We can use them for medical treatment and therapeutic cloning using stem cells from the patient.
• Why is therapeutic cloning good?


  It's genetically identical to the patient so it won't be rejected from the patients immune system and it requires fewer complications
• What are some sources of embryonic cells?


  Spare embryos left over from fertility treatments. Cuistom made embryos created using the same technique used which created Dolly the sheep but the embryo is not implanted. This only works for stem cells (cloning.
• What are some uses of plant stem cells?


  produce clones of plants quicker and cheaper. Grow more rare plant species to prevent them being wiped out. Grow identical plants with desirable features ie crops with disease resistance