Overview of Aging TheoriesAccumulative-Waste TheoryThe biological theory of ageing that points to a buildup of cells ofwasteproductsthatpresumablyinterfereswithmetabolismDNA damage and DNA repairLoss of repair efficiency with age leads to somatic mutation withdeleteriouseffects.Mitochondrial free radical theoryDamage to mitochondria and cellular proteins from free radicalsgenerated in mitochondria causes cell agingWear-and-TearTheory（磨损学说）The very general idea that changes associated with ageing arethe result of chance damagethat accumulates overtime
• Accumulative-Waste Theory The biological theory of ageing that points to a buildup of cells of waste products that presumably interferes with metabolism. • DNA damage and DNA repair Loss of repair efficiency with age leads to somatic mutation with deleterious effects. • Mitochondrial free radical theory Damage to mitochondria and cellular proteins from free radicals generated in mitochondria causes cell aging. • Wear-and-Tear Theory (磨损学说） The very general idea that changes associated with ageing are the result of chance damage that accumulates over time. . Overview of Aging Theories
Mitochondrial freeradical theory of aging-Harman DAging.chemistryHARMAJGerontPMID:11RelatedThe bidHarmarble.JAmGePMID:50RelatedHarman's93idbirthdayDatePublished:TuesdayFebruary1720o9
Mitochondrial free radical theory of aging-Harman D Harman’s 93id birthday. Date Published: Tuesday, February 17, 2009
Key points of Harman's theory* The common aging process is the initiation offree radical reactions,owing to theirinnateability to producerandom change due to thehighchemical reactivity of the intermediatefree radicals.*Theorywasextended in1972withthesuggestion that most free radicals wereinitiated by the mitochondria at an increasingrate with age,and the life span is determinedbytherateoffreeradicaldamagetothemitochondria
Key points of Harman’s theory The common aging process is the initiation of free radical reactions, owing to their innate ability to produce random change due to the high chemical reactivity of the intermediate free radicals. Theory was extended in 1972 with the suggestion that most free radicals were initiated by the mitochondria at an increasing rate with age, and the life span is determined by the rate of free radical damage to the mitochondria
Free radicals· Free radical:odd number ofelectrons.Chemicalswctron are highlyther molecules.reactive, reaIl are wellMostchemiccontrolled--reing conditions orenzymes. Bd can react withthermodynarmost moleocovalentbondsMoses Gomberg (1866-1947), thefather of radical chemistry
• Free radical: a chemical with an odd number of electrons. • Chemicals with an unpaired electron are highly reactive, readily combine with other molecules. • Most chemical reactions in a cell are well controlled-require specific starting conditions or enzymes. But free radicals are thermodynamically unstable and can react with most molecules and break most covalent bonds. Free radicals Moses Gomberg (1866-1947), the father of radical chemistry
Freeradicals. Normal bond:‘:'represents a pair of electionsBreakingabond:A:B->A:+B+Productsareions.Freeradicalformation:A:B->A-+BProducts each have an unpaired electron!Free radical breakdown of H,O:H:O:H->-OH+HForms Hydroxyl radical and hydrogen radical
• Normal bond: ‘:’ represents a pair of elections Breaking a bond: A:B -> A:- + B+ Products are ions. • Free radical formation: A:B -> A· + B· Products each have an unpaired electron! Free radical breakdown of H2O: H:O:H -> ·OH + H· Forms Hydroxyl radical and hydrogen radical. Free radicals