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Mitochondrial Theory Of Ageing
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 and was developed in the works of Linnane and coworkers (1989). The second was proposed by A. N. Lobachev in 1978. The mitochondrial free radical theory of ageing (MFRTA) proposes that free radicals produced by mitochondrial activity damage cellular components, leading to ageing. Mitochondria are cell organelles which function to provide the cell with energy by producing ATP (adenosine triphosphate). During ATP production electrons can escape the mitochondrion and react with water, producing reactive oxygen species, ROS for short. ROS can damage macromolecules, including lipids, proteins and DNA, which is thought to facilitate the process of ageing. In the 1950s Denham Harman proposed the free radical theory of ageing, which he later expanded to the MFRTA. Whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Radicals
In chemistry, a radical, also known as a free radical, is an atom, molecule, or ion that has at least one unpaired valence electron. With some exceptions, these unpaired electrons make radicals highly chemically reactive. Many radicals spontaneously dimerize. Most organic radicals have short lifetimes. A notable example of a radical is the hydroxyl radical (HO·), a molecule that has one unpaired electron on the oxygen atom. Two other examples are triplet oxygen and triplet carbene (꞉) which have two unpaired electrons. Radicals may be generated in a number of ways, but typical methods involve redox reactions. Ionizing radiation, heat, electrical discharges, and electrolysis are known to produce radicals. Radicals are intermediates in many chemical reactions, more so than is apparent from the balanced equations. Radicals are important in combustion, atmospheric chemistry, polymerization, plasma chemistry, biochemistry, and many other chemical processes. A majority of n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
