{"articleData":{"id":561,"name":"Most of a cell's DNA is not translated - AL only (3.8.2.1)","description":"An overview of most of a cell's DNA is not translated - AL only (3.8.2.1) from AQA A level Biology","image":"https://d3nzlfkeryzt6j.cloudfront.net/bzar30vpa9p2wj6dee5mu5im55by","image_content_type":"image/svg+xml","seo_image":"https://d3nzlfkeryzt6j.cloudfront.net/j54vg50ogy01mn1a4akudsiwpkgt","chapters":[{"id":3166,"name":"Stem cells ","slug":"stem-cells","blocks":[{"id":15259,"block_type":"Tip","block":{"button_label":null,"display_type":"image","id":7348,"image_a_alt_text":"Diagram titled 'Types of Stem Cells' with three sections. Top section shows 'Totipotent' cells in a circular cluster labeled 'Develop into all cell types' and 'Pluripotent' cells in a circular cluster labeled 'Develop into many cell types'. Middle section shows 'Multipotent' cells with arrows pointing to illustrations of a brain labeled 'Nervous tissue' and skin labeled 'Epidermis', with text 'Develop into'. Bottom section shows 'Unipotent' with an illustration of an 'Epidermal stem cell', an arrow labeled 'Develop into' pointing to an illustration of skin layers labeled 'Keratinocytes of epidermis'. © Medify at the bottom.","image_b_alt_text":null,"name":"2_BIO_18_051","text_content_a_html":"

There are four key types of stem cells.

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Totipotent cells are cells such as fertilised eggs. Totipotent cells can develop into new organisms, including the placenta, found in early embryos.

Pluripotent cells are found in embryos and can develop into almost any type of cell.

Multipotent cells are found in adults and umbilical cords. Multipotent cells can differentiate into only certain types of cells, such as blood cells.

Unipotent cells can only differentiate into one type of cell; they are produced by multipotent cells.

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Unipotent cells can be altered in a lab to produce induced pluripotent stem (iPS) cells, which are similar to pluripotent cells.

Genetic information is reactivated so the cell is able to express a wider variety of genes. This allows the cell to differentiate into many types of cell.

iPS cells could replace embryonic stem cells in research, as using adult tissue raises fewer ethical concerns.

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iPS cells can be used to treat medical conditions, such as Parkinson’s, leukaemia and osteoporosis.

The iPS cells can be used to generate new tissue, which can replace the damaged tissue.

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