Question

1. What is a a mutation, a mutagen, and why is it important to investigate the mutagenicity of common substances?

Answer 1

MUTATION

Mutations are changes in the genetic sequence, and they are a main cause of diversity among organisms. These changes occur at many different levels, and they can have widely differing consequences. In biological systems that are capable of reproduction, we must first focus on whether they are heritable; specifically, some mutations affect only the individual that carries them, while others affect all of the carrier organism's offspring, and further descendants. For mutations to affect an organism's descendants, they must occur in cells that produce the next generation and affect the hereditary material. Ultimately, the interplay between inherited mutations and environmental pressures generates diversity among species.

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MUTAGEN

Mutagen, any agent capable of altering the genetic constitution of a cell by changing the structure of the hereditary material, deoxyribonucleic acid (DNA). Many forms of electromagnetic radiation e.g cosmic rays, X rays, ultraviolet ligh) are mutagenic, as are a variety of chemical compounds. The effects of some mutagens are potentiated (increased) or suppressed in some organisms by the presence of certain other, nonmutagenic substances; oxygen, for example, makes cells more sensitive to the mutagenic effects of X rays.

it important to investigate the mutagenicity of common substances because the foods that we eat contain a vast number of separate chemical entities: several thousand as additives and many times this number as natural constituents. Of course, most of these chemicals are present in relatively low concentrations, but if potent carcinogens exist, even at low concentrations in commonly consumed foods, they may warrant concern. The problem, therefore, is how to test the very large number of chemicals present in the complex mixtures we call food to determine whether or not they may be contributing to our risk for cancer.