Cancer

1. Question 1

   Which specific mechanism triggers the uncontrolled cell division characteristic of cancer?

   • A) Increased rate of osmosis
   • B) Changes in genetic material
   • C) Loss of ribosome function
   • D) Excessive water absorption
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   Answer: Changes in genetic material

   Cancer occurs when changes or mutations in the DNA lead to uncontrolled cell division. These mutations disrupt the normal instructions that tell a cell when to divide and when to stop, causing the cell to multiply rapidly and form a tumour.

2. Question 2

   What is the primary difference between a benign tumour and a malignant tumour?

   • A) Malignant tumours grow faster
   • B) Benign tumours invade tissues
   • C) Malignant tumours spread away
   • D) Benign tumours are dangerous
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   Answer: Malignant tumours spread away

   Benign tumours are growths of abnormal cells that remain contained in one area, usually within a membrane, and do not invade other tissues. In contrast, malignant tumours are cancerous; they can break apart, enter the bloodstream, and spread to other parts of the body to form secondary tumours.

3. Question 3

   Which term describes the process by which malignant cancer cells spread to secondary sites in the body?

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   Answer: metastasis

   Metastasis occurs when cancer cells break away from the original primary tumour and travel through the circulatory or lymphatic systems. Once these cells lodge in distant tissues or organs, they continue to divide, creating secondary tumours.

More Edexcel Biology topics

• Antibiotics & drug discovery
• Biodiversity & global warming
• Biotic & abiotic factors
• Blood vessels — artery / vein / capillary
• Blood — red cells, white cells, plasma, platelets
• Cell structure
• Classification
• Communicable diseases
• Coronary heart disease & lifestyle
• Cycles in ecosystems
• DNA structure
• Decomposition