Carcinogen: Difference between revisions
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A carcinogen is a [[Cancer|cancer]] causing substance. Examples of this are substances seen in tobacco smoke. These includes tar, [[ | A carcinogen is a [[Cancer|cancer]] causing substance. Examples of this are substances seen in tobacco smoke. These includes tar, [[nicotine|nicotine]], [[Carbon monoxide|carbon monoxide]], etc.<br> | ||
Carcinogens arise in the body after metabolic activation of environmental chemicals by enzymes such as the [[ | Carcinogens arise in the body after metabolic activation of environmental chemicals by enzymes such as the [[P450 enzymes|p450 enzymes]]. These environmental chemicals remain biologically inert until they are taken up into tissue when they then become activated, becoming a carcinogen. The carcinogen then spontaneously becomes a reactive intermediate, forms [[DNA adducts|DNA adducts]] and causes genetic damage resulting in cancer.<br> | ||
The body has defensive mechanisms at each of these steps to prevent the carcinogen leading to cancer such as: | The body has defensive mechanisms at each of these steps to prevent the carcinogen leading to cancer such as: | ||
#[[Metabolic detoxification|Metabolic detoxification]] by the GST ([[ | #[[Metabolic detoxification|Metabolic detoxification]] by the GST ([[Glutathione-S-transferase|glutathione-S-transferase]]) [[Enzyme|enzymes]] | ||
#[[DNA repair|DNA repair]] | #[[DNA repair|DNA repair]] | ||
#Cell [[Apoptosis|apoptosis]]. | #Cell [[Apoptosis|apoptosis]]. | ||
However if this defence fails and there are not enough metabolic detoxification enzymes or the DNA is replicated with the wrong base order, cancer occurs. | However if this defence fails and there are not enough metabolic detoxification enzymes or the DNA is replicated with the wrong base order, cancer occurs. | ||
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Revision as of 10:32, 28 November 2014
A carcinogen is a cancer causing substance. Examples of this are substances seen in tobacco smoke. These includes tar, nicotine, carbon monoxide, etc.
Carcinogens arise in the body after metabolic activation of environmental chemicals by enzymes such as the p450 enzymes. These environmental chemicals remain biologically inert until they are taken up into tissue when they then become activated, becoming a carcinogen. The carcinogen then spontaneously becomes a reactive intermediate, forms DNA adducts and causes genetic damage resulting in cancer.
The body has defensive mechanisms at each of these steps to prevent the carcinogen leading to cancer such as:
- Metabolic detoxification by the GST (glutathione-S-transferase) enzymes
- DNA repair
- Cell apoptosis.
However if this defence fails and there are not enough metabolic detoxification enzymes or the DNA is replicated with the wrong base order, cancer occurs.