Mutagen - History, Where Mutagens Exist, How Mutagens Work, Somatic Vs. Germline Mutations, Types Of Mutagens
cell dna cells changes
In the living cell, deoxyribonucleic acid (DNA) undergoes frequent chemical change, especially when it is being replicated. Most of these changes are quickly repaired. Those that are not, result in a mutation. Thus, mutation is a failure of DNA repair. Mutagens are chemicals or physical factors (such as radiation) that increase the rate of mutation in the cells of bacteria, plants, and animals (including humans). Most mutagens are of natural origin and are not just a modern phenomenon.
Mutagens can be found in the food we eat, the air we breath, or the ground we walk on. Very small doses of a mutagen usually have little effect while large doses of a mutagen could be lethal. DNA in the nuclei of all cells encodes proteins, which play important structural and functional (metabolic) roles in the cell. Mutagens typically disrupt the DNA of cells, causing changes in the proteins that the cell produces, which can lead to abnormally fast growth (cancer), or even cell death. In rare incidences, mutagens can even cause protein changes that are beneficial to the cell.
Additional Topics
In England in 1775, Dr. Percivall Pott wrote a paper on the high incidence of scrotal cancer in chimney sweeps who were typically boys small enough to fit inside chimneys and clean out the soot. Pott suggested that chimney soot contained carcinogens that could cause the growth of the warts seen in scrotal cancer. Over a 150 years later, chimney soot was found to contain hydrocarbons capable of mut…
Mutagens can be found in foods, beverages, and drugs. Sometimes a substance is mutagenic because it is converted in the body into something harmful. Regulatory agencies are responsible for testing food and drugs to insure that the public is not unknowingly exposed to mutagens. However, some mutagen-containing substances are not tightly controlled. One such substance is found in the tobacco of ciga…
The significance of mutations is profoundly influenced by the distinction between germline and soma. Mutations in somatic (body) cells are not transferred to offspring. Mutations that occur in a somatic cell, in the bone marrow or liver for example, may damage the cell, make the cell cancerous or even kill the cell. Whatever the effect, the ultimate fate of that somatic mutation is to disappear wh…
Chemical mutagens are classified as alkylating agents, cross-linking agents, and polycyclic aromatic hydrocarbons (PAHs). Alkylating agents act by adding molecular components to DNA bases, which alters the protein product. Cross-linking agents create covalent bonds with DNA bases, while PAHs are metabolized by the human body into other potentially mutagenic molecules. Radiation is another potent m…
In addition to mutagen-induced DNA changes, spontaneous mutations occur in the dividing cells of the human body every day. The nuclei of the cells have repair enzymes, which remove mutations and restore mutated DNA to its original form. If these natural DNA repair mechanisms fail to keep up with the rate of mutation or the repair mechanisms themselves are defective, disease can result. This latter…
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