Stem cells

• Cell Differentiation

  The process by which each cell develops into a specialised strict
• Why are some cells specialised?

  Although all cells contain all genes, only certain genes are expressed in anyone cell at any time
• Which genes are permanently expressed in all cells?


  The genes that code for essential chemicals, such as the enzymes involved in respiration
• Totipotency

  The ability of a single cell to divide and produce all the differentiated cells in an organism, including all the extraembryonic tissues
• How do some totipotent cells specialise for a particular function?

  During the process of cell specialisation only some of the genes are expressed. This means only part of the DNA of the cell is translated into proteins. This means that the cell only makes proteins that it requires to carry out its specialised function.
• How are genes prevented from expressing themselves?

  Preventing transcription and so preventing the production of mRNA, and preventing translation
• Stem cells

  Undifferentiated dividing cells that occurring as a animal tissues and need to be constantly replace. They have the ability to provide a form of identical copy of themselves in a process called self renewal
• Embryonic stem cells

  Come from embryos in the early stages of development. They can differentiate into any type of cell in the initial stages of development
• Umbilical cord stem cells


  Are derived from umbilical cord blood and are similar to adult stem cells
• Placental stem cells


  Found in the placenta and develop into specific types of cells
• Adult stem cells

  Found in the body tissues of the fetus-they are specific to a particular tissue or organ
• Totipotent stem cells

  Found in the early embryo and can develop into any different type of cell
• Pluripotent stem cells


  Found in embryos and can differentiate into almost any type of cell
• Multipotent stem cells


  Found in adults and can usually differentiate into a number of different specialised cells. They usually develop into cells a particular type, for example stem cells in the bone marrow can produce any type of blood cell
• Unipotent stem cells


  Can only differentiate into a single type of cell. They are derived from multipotent stem cells and are made in adult tissue
• Induced pluripotent stem cells


  They are a type of pluripotent cell that is produced from unipotent stem cells
• How are induced pluripotent stem cells made?

  A unit potent stem cell taken from the body is genetically altered in a laboratory to make it acquire characteristics of embryonic stem cells which are a type of pluripotent cell. In order to do this they induce genes and transcription factors within the cell to express themselves.
• How are induced pluripotent stem cells is similar to embryonic stem cells?

  They are capable of self renewal so can potentially devise to produce a limitless supply, They are similar in form and function, and as such could replace embryonic stem cells in medical research and treatment
• What are the uses of pluripotent cells in treating human disorders?

  They can be used to really grow tissues that have been damaged in some way, Either by accident or due to disease