Name the kind of carcinogen, physical, chemical or biological, in each case…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Name the kind of carcinogen, physical, chemical or biological, in each case.
- X-rays used again and again on the same part of the body.
- The smoke of a cigarette.
- A virus that carries a viral oncogene.
- Ultraviolet rays from the Sun, which fall on the skin of a person for years.
- Gamma rays from a radioactive source.
- Say what happens to a proto-oncogene when one of these agents activates it.
Need a reminder? The key ideaShow
Normal cells stop dividing when they touch, which is contact inhibition. A malignant tumour invades and spreads by metastasis, and a benign tumour does not. After doublings, a tumour that grew from one cell has cells. Carcinogens may be physical, chemical or biological.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. (a) Physical. X-rays are ionising radiation.
Step 2. (b) Chemical. Tobacco smoke is the main cause of lung cancer.
Step 3. (c) Biological. It is an oncogenic virus.
Step 4. (d) Physical. UV is a non-ionising radiation that damages DNA.
Step 5. (e) Physical. Gamma rays are ionising.
Step 6. (f) It becomes an oncogene, and the cell divides without control.
Answer: (a) physical; (b) chemical; (c) biological; (d) physical; (e) physical; (f) it becomes an oncogene.
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