A-Level Biology AQA 7402

Totipotent cells can divide and produce any type of body cell.

During development, totipotent cells translate only part of their DNA, resulting in cell specialisation.

Totipotent cells occur only for a limited time in early mammalian embryos.

Pluripotent cells are found in embryos; multipotent and unipotent cells are found in mature mammals and can divide to form a limited number of different cell types.

• Pluripotent stem cells can divide in unlimited numbers and can be used in treating human disorders.
• Unipotent cells, exemplified by the formation of cardiomyocytes.
• Induced pluripotent stem cells (iPS cells) can be produced from adult somatic cells using appropriate protein transcription factors.

Students should be able to evaluate the use of stem cells in treating human disorders.