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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 ...
The mitochondrial theory of ageing has two varieties: free radical and non-free radical. The first is one of the variants of the free radical theory of ageing. It was formulated by J. Miquel and colleagues in 1980 [1] and was developed in the works of Linnane and coworkers (1989). [2] The second was proposed by A. N. Lobachev in 1978. [3]
Hydrogen abstraction from the 1’-deoxyribose carbon by the hydroxyl radical creates a 1 ‘-deoxyribosyl radical. The radical can then react with molecular oxygen, creating a peroxyl radical which can be reduced and dehydrated to yield a 2’-deoxyribonolactone and free base. A deoxyribonolactone is mutagenic and resistant to repair enzymes.
The lipid hydroperoxyl radical (LOO•) can also undergo a variety of reactions to produce new radicals. [citation needed] The additional lipid radical (L•) continues the chain reaction, whilst the lipid hydroperoxide (LOOH) is the primary end product. [6] The formation of lipid radicals is sensitive to the kinetic isotope effect.
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]
In chemistry, a radical, also known as a free radical, is an atom, molecule, or ion that has at least one unpaired valence electron. [1] [2] With some exceptions, these unpaired electrons make radicals highly chemically reactive. Many radicals spontaneously dimerize. Most organic radicals have short lifetimes.
The hydroperoxyl radical, also known as the hydrogen superoxide, is the protonated form of superoxide with the chemical formula HO 2, also written HOO •. This species plays an important role in the atmosphere and as a reactive oxygen species in cell biology.
The and pH of a solution are related by the Nernst equation as commonly represented by a Pourbaix diagram (– pH plot).For a half cell equation, conventionally written as a reduction reaction (i.e., electrons accepted by an oxidant on the left side):