CAIE A Level Biology 9700 · The mitotic cell cycle
Human skin is constantly renewed as stem cells in the epidermis divide by mitosis to replace cells lost from the surface. In an inherited condition, skin stem cells have telomeres that are much shorter than normal. Outline the mitotic cell cycle and the role of mitosis in replacing damaged skin cells. With reference to telomeres and the control of cell division, explain how a failure to regulate the cell cycle could lead to the formation of a tumour.
7 marks, so the mark scheme is looking for about 7 separate creditworthy points. Making the same point twice in different words earns it once.
Outline means: Give the main points briefly. Less detail than describe, but every key step has to be there. One short line per step, in order. The marks are for coverage, not depth.
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