Cancer is a group of diseases caused by uncontrolled mitosis. An abnormal mass called a tumour forms.These tumours can be malignant or benign. Benign tumours stop growing or grow very slowly. Malignant tumour cells break off and travel to other parts of the body where they form secondary tumours.The proteins that regulate the cell cycle have undergone spontaneous mutation.Proto-oncogenes are genes that drive the cell cycle forward, tumour suppressor genes code for proteins that normally operate to restrict cellular growth and division or even promote programmed cell death (apoptosis).If proto-oncogenes mutate to oncogenes they promote continuous cell division. If tumour suppressor gene mutate they fail to stop cell division.
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Specification: OCR Biology A (H020), AS-level, 2.1.6 Cell division, cell diversity and cellular organisation. Topic: Cell Division.
Key terms in this lesson
- apoptosis
- Programmed cell death, a controlled process by which unwanted or damaged cells are removed.
- mitosis
- Nuclear division producing two daughter nuclei that are genetically identical to the parent nucleus, used in growth, repair and asexual reproduction.
- gene
- A length of DNA that codes for a specific polypeptide.
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