bio paper - 1 In recent decades it seems as though the...

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In recent decades, it seems as though the process of aging has slowly emerged as an important field science. With a great deal of literature and scientific work dedicated solely to the subject of aging and its underlying causes, aging has become somewhat of a scientific quest. Whether it is the human obsession with mortality or trying to maintain one’s youthful appearance, aging is something experienced universally by all organisms, including viruses. Recent studies have tried to find many different explanations for aging including research on free radicals, the role of different enzymes and molecules, DNA damage, and DNA repair (Fisher, 1999). To focus more closely on the topic, the role of DNA damage and DNA repair in aging will be discussed. A common but harmful thing occurs in our bodies almost every day; DNA damage. As dangerous as this sounds most DNA damage goes unnoticed because of processes in our cells that work to fix any damage caused. Common causes of DNA damage include spontaneous and gene-inherited mutations, which can occur during cell reproduction (spontaneous) and during the formation of germ cells (gene-inherited) (Gensler & Bernstein, 1981). The formation of reactive oxygen species, also known as free radicals, also can cause oxidative damage to DNA (Lombard et al. , 2005). Ultraviolet radiation, X-rays, certain toxins, chemotherapy, and the harmful chemicals in cigarette smoke and chewing tobacco have all been shown in studies to cause some sort of damage to DNA. As dangerous and harmful as these appear to be most of the damage does become fixed and if it does not, many cells die. In the case of gene-inherited mutations in germ cells, if there is any severe genetic defect once the zygote has formed that would inhibit normal cell function or normal function of the individual, the zygote will terminate. If the cell is unable to repair the damaged DNA one of three different states may occur: senescence, apoptosis, or unregulated cell division, which can cause the growth of a tumor or the development of cancer (Lombard et al ., 2005). Once damage has been inflicted upon DNA the cell begins a series of steps to initialize the repair of DNA (Fisher, 1999). DNA damage can be repaired by direct reversal. Direct reversal fixes DNA damage by chemically reversing it. Usually direct reversal occurs when there is damage to the bases in DNA and not to the phospodiester backbone. Ultraviolet radiation is a common cause of damage to DNA and is frequently repaired using direct reversal to repair the damage caused by thymine dimers. In single- 1
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This note was uploaded on 04/08/2008 for the course BIO 211 taught by Professor Reedy during the Fall '07 term at Creighton.

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bio paper - 1 In recent decades it seems as though the...

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