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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 ...
Reactive oxygen species and oxygen. ROS are highly reactive, oxygen-containing chemical species, which include superoxide, hydrogen peroxide and hydroxyl radical.If the complexes of the ETC do not function properly, electrons can leak and react with water, forming ROS.
Reactive oxygen species are implicated in cellular activity to a variety of inflammatory responses including cardiovascular disease. They may also be involved in hearing impairment via cochlear damage induced by elevated sound levels , in ototoxicity of drugs such as cisplatin , and in congenital deafness in both animals and humans.
Reactive oxygen species levels increase with age in these mutant strains and show a similar pattern to the pattern of DNA damage increase with age. Thus it appears that superoxide dismutase plays a substantial role in preserving genome integrity during aging in S. cerevisiae. SOD2 knockout or null mutations cause growth inhibition on ...
Cells can also be induced to senesce by DNA damage in response to elevated reactive oxygen species (ROS), activation of oncogenes, and cell-cell fusion. Normally, cell senescence is reached through a combination of a variety of factors (i.e., both telomere shortening and oxidative stress). [13]
Reactive oxygen species (ROS) have been discarded as unwanted byproducts of oxidative phosphorylation in mitochondria by the proponents of the free-radical theory of aging promoted by Denham Harman. The free-radical theory states that compounds inactivating ROS would lead to a reduction of oxidative stress and thereby produce an increase in ...
8-Oxoguanine (8-hydroxyguanine, 8-oxo-Gua, or OH 8 Gua) is one of the most common DNA lesions resulting from reactive oxygen species [2] modifying guanine, and can result in a mismatched pairing with adenine resulting in G to T and C to A substitutions in the genome. [3] In humans, it is primarily repaired by DNA glycosylase OGG1.
Lipid peroxidation, or lipid oxidation, is a complex chemical process that leads to oxidative degradation of lipids, [1] resulting in the formation of peroxide and hydroperoxide derivatives. [2]