B2 Cell transport

• Stem cell


  An undifferentiated cell that can develop into one or more types of specialised cell
• Types of stem cell in mammals


  • Adult stem cells
  • Embryonic stem cells
• Adult stem cells


  • Can only differentiate to form certain specific parts of the body
  • For example, stem cells in bone marrow can only differentiate into types of blood cell
• Embryonic stem cells


  • Can differentiate into any type of specialised cell in the body
  • For example, a nerve cell or a muscle cell
• Plant meristem


  • Can differentiate into all cell types
  • They can be used to create clones of whole plants
• Therapeutic cloning


  Cells from a patient's body are used to create a cloned early embryo of themselves, and stem cells from this embryo can be used for medical treatments and growing new organs
• These stem cells have the same genes as the patient, so are less likely to be rejected when transplanted