Brainlag PlusHow tumours form, benign and malignant tumours and secondary tumours, lifestyle and genetic risk factors and carcinogens, tumour growth by cell division, and working with cancer data.
How a tumour forms
Cancer is the result of changes in cells that lead to uncontrolled growth and division.
The cells divide by mitosis again and again, without the normal checks, and form a lump called a tumour.
- Benign tumour: growths of abnormal cells contained in one area, usually within a membrane. They do not invade other parts of the body. They can still be harmful, for example by pressing on the brain.
- Malignant tumour: a cancer. Its cells invade neighbouring tissues and can spread to different parts of the body in the blood, where they form secondary tumours.
- Tumour cells divide once every 24 hours, starting from 5 cells
- In 10 days: 10 × 24 = 240 hours; 240 ÷ 24 = 10 divisions
- Cells = 5 × 2¹⁰ = 5 × 1024 = 5120
- = 5.12 × 10³ cells
Each division doubles the number: multiply by 2 once for every division (2¹⁰), not by 2 × 10.
The rest of this lesson and its 10 practice questions are in Plus.
Screen 1 of 4, free to read.
- 10 exam-style questions, marked as you go, each with a worked solution
- Anything you get wrong is saved to your flashcards