what are some physical and chemical agents that cause mutations?
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The chemical or physical agents that cause mutations are called mutagens. Examples of physical mutagens are ultraviolet (UV) and gamma radiation. Radiation exerts its mutagenic effect either directly or by creating free radicals that in turn have mutagenic effects.
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['Mutations—change in genes (DNA sequence) or chromosomes.', 'Gene recombination—mixing of genes that result from meiosis and sexual reproduction.']
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Acquired (or somatic) mutations occur at some time during a person's life and are present only in certain cells, not in every cell in the body. These changes can be caused by environmental factors such as ultraviolet radiation from the sun, or can occur if an error is made as DNA copies itself during cell division.
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DNA is a dynamic and adaptable molecule. As such, the nucleotide sequences found within it are subject to change as the result of a phenomenon called mutation. Depending on how a particular mutation modifies an organism's genetic makeup, it can prove harmless, helpful, or even hurtful.
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The majority of mutations are neutral in their effects on the organisms in which they occur. Beneficial mutations may become more common through natural selection. Harmful mutations may cause genetic disorders or cancer.
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['mutation.', 'random mating between organisms.', 'random fertilization.', 'crossing over (or recombination) between chromatids of homologous chromosomes during meiosis.']
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How Melanin Can Hurt Us. Researchers say UV radiation generates reactive oxygen and nitrogen that energizes an electron in melanin. That energy can cause DNA lesions, which can lead to cancer-causing mutations. The lesions typically appear less than one second after UV radiation exposure.
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Somatic Mutations. Somatic or acquired mutations are the most common cause of cancer. These mutations occur from damage to genes in an individual cell during a person's life. Cancers that occur because of somatic mutations are referred to as sporadic cancers.
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When a mutation alters a protein that plays a critical role in the body, it can disrupt normal development or cause a medical condition. A condition caused by mutations in one or more genes is called a genetic disorder. In some cases, gene mutations are so severe that they prevent an embryo from surviving until birth.
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A mutation is a change in DNA, the hereditary material of life. An organism's DNA affects how it looks, how it behaves, and its physiology. So a change in an organism's DNA can cause changes in all aspects of its life. Mutations are essential to evolution; they are the raw material of genetic variation.
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A mutagen is a chemical or physical phenomenon, such as ionizing radiation, that promotes errors in DNA replication. Exposure to a mutagen can produce DNA mutations that cause or contribute to diseases such as cancer.
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frameshift mutation / frame-shift mutation; frameshift. A frameshift mutation is a genetic mutation caused by a deletion or insertion in a DNA sequence that shifts the way the sequence is read. A DNA sequence is a chain of many smaller molecules called nucleotides.
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Genetic Change in Viruses. Viruses are continuously changing as a result of genetic selection. They undergo subtle genetic changes through mutation and major genetic changes through recombination. Mutation occurs when an error is incorporated in the viral genome.
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Harmful Mutations By the same token, any random change in a gene's DNA is likely to result in a protein that does not function normally or may not function at all. Such mutations are likely to be harmful. Harmful mutations may cause genetic disorders or cancer.
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Some mutations can be harmful. A change in the gene might produce a faulty or non-functioning protein, resulting in a genetic disease, such as cystic fibrosis.
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As radioactive material decays, or breaks down, the energy released into the environment has two ways of harming a body that is exposed to it, Higley said. It can directly kill cells, or it can cause mutations to DNA. If those mutations are not repaired, the cell may turn cancerous.
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Terms in this set (13) Chemicals that cause mutations if cells are exposed to them at high frequencies or for prolonged periods of time. Chemical mutagens cause a change in DNA that alters the function of proteins, as a result, cellular processes are impaired.