3.8.2.1 Most of the cell's DNA is not translated

• Stem cells are undifferentiated cells that can develop into different cell types. The types of stem cells include:

  • Totipotent
  • Pluripotent
  • Multipotent
  • Unipotent
• Totipotent stem cells are able to differentiate into any type of cell found in the body and into embryonic cells such as those in the placenta.

  • They occur only for a limited time in early mammalian embryos
  • During development, they translate only part of their DNA, resulting in cell specialisation
• Pluripotent stem cells can differentiate to form any cell type in the body, but cannot form embryonic cells (placenta cells).

  • They are found in embryos
  • They are often used in replacing damaged tissues in human disorders.
• Multipotent stem cells can differentiate into a limited range of cells (e.g., bone marrow stem cells → blood cells).

  • They are found in mature mammals (adults).
• Unipotent stem cells can only differentiate into one type of cell (e.g., cardiomyocytes in the heart).

  • They are found in mature mammals (adults).
• Induced Pluripotent Stem Cells (iPSCs) are pluripotent stem cells created from unipotent stem cells.

  • Reprogramming adult somatic cells into pluripotent stem cells using specific genes and transcription factors.
  • Useful for regenerative medicine.