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Hydroxyl radicals can attack the deoxyribose DNA backbone and bases, potentially causing a plethora of lesions that can be cytotoxic or mutagenic. Cells have developed complex and efficient repair mechanisms to fix the lesions. In the case of free radical attack on DNA, base-excision repair is the repair mechanism used. Hydroxyl radical ...
The free radical theory of aging states that organisms age because cells accumulate free radical damage over time. [1] A free radical is any atom or molecule that has a single unpaired electron in an outer shell. [2] While a few free radicals such as melanin are not chemically reactive, most biologically relevant free radicals are highly ...
This occurrence is when there is an imbalance of free radicals and antioxidants in the cells of the organism, largely due to pollution and radiation in the environment. Obligate aerobes survive this phenomenon by using the organism's immune system to correct the imbalance.
In living organisms, which are composed mostly of water, majority of the damage is caused by the reactive oxygen species, free radicals produced from water. The free radicals attack the biomolecules forming structures within the cells , causing oxidative stress (a cumulative damage which may be significant enough to cause the cell death, or may ...
Oxidative stress mechanisms in tissue injury. Free radical toxicity induced by xenobiotics and the subsequent detoxification by cellular enzymes (termination).. Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage. [1]
Free radicals are reactive molecules produced by cellular and environmental processes, and can damage the elements of the cell such as the cell membrane and DNA and cause irreversible damage. The free-radical theory of aging proposes that this damage cumulatively degrades the biological function of cells and impacts the process of aging. [18]
Free radical toxicity induced by xenobiotics and the subsequent detoxification by cellular enzymes (termination). Effects of ROS on cell metabolism are well documented in a variety of species. [19] These include not only roles in apoptosis (programmed cell death) but also positive effects such as the induction of host defence [36] [37] genes ...
Free-radical theory: Damage by free radicals, or more generally reactive oxygen species or oxidative stress, create damage that may give rise to the symptoms we recognise as ageing. [99] The effect of calorie restriction may be due to increased formation of free radicals within the mitochondria , causing a secondary induction of increased ...