Uncontrolled Cell Division (Edexcel GCSE Biology: Combined Science)

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Uncontrolled Cell Division

  • Cells in the body divide by mitosis to produce more cells - this is essential for growth and to repair damaged cells
    • For example, the cells of the intestines are constantly dividing to replace those that are shed as food moves through the digestive system

  • Mitosis is just one part of the cell cycle which is regulated by many different genes to ensure that cells divide only when they need to and stop when required
  • Cancer is caused as a result of mutations in the DNA of cells that lead to uncontrolled cell growth and division - this can result in the formation of a tumour (a mass of cells)
    • Usually, tumours form as a result of loss of control of the cell cycle

Types of Tumour

  • There are two main types of tumour:
    • Benign tumours
    • Malignant tumours

  • Benign tumours are growths of abnormal cells which are contained in one area, usually within a membrane
    • Crucially, benign tumours do not invade other parts of the body
    • This means these tumours are not considered cancerous

  • Malignant tumours are cancerous – the cells of these tumours invade neighbouring tissues and spread to different parts of the body via the blood and lymphatic system where they form secondary tumours
    • Malignant tumours are more likely to disrupt the functioning of the organ they originate in (as they invade healthy tissue) and the organs they spread to – this is why they are dangerous and how they lead to death

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Ruth

Author: Ruth

Expertise: Biology

Ruth graduated from Sheffield University with a degree in Biology and went on to teach Science in London whilst also completing an MA in innovation in Education. She gained 10 years of teaching experience across the 3 key science disciplines and physical education. Ruth decided to set up a tutoring business to support students in her local area. Ruth has worked with several exam boards and loves to use her experience to produce educational materials which make the mark schemes accessible to all students.