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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.
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 DNA damage theory of aging proposes that aging is a consequence of unrepaired accumulation of naturally occurring DNA damage. Damage in this context is a DNA alteration that has an abnormal structure. Although both mitochondrial and nuclear DNA damage can contribute to aging, nuclear DNA is the main subject of this analysis.
Stochastic theories of aging are theories suggesting that aging is caused by small changes in the body over time and the body's failure to restore the system and mend the damages to the body. Cells and tissues are injured due to the accumulation of damage over time resulting in the diminished functioning of organs.
Senescence (/ sɪˈnɛsəns /) or biological aging is the gradual deterioration of functional characteristics in living organisms. Whole organism senescence involves an increase in death rates or a decrease in fecundity with increasing age, at least in the later part of an organism's life cycle. [ 1 ][ 2 ] However, the resulting effects of ...
Society portal. v. t. e. Gerontology (/ ˌdʒɛrənˈtɒlədʒi / JERR-ən-TOL-ə-jee) is the study of the social, cultural, psychological, cognitive, and biological aspects of aging. The word was coined by Ilya Ilyich Mechnikov in 1903, from the Greek γέρων (gérōn), meaning "old man", and -λογία (-logía), meaning "study of". [ 1 ...
A telomere is a region of repetitive sequencesat each end of the chromosomesof most eukaryotes. Telomeres protect the end of the chromosome from DNA damageor from fusion with neighbouring chromosomes. The fruit fly Drosophila melanogasterlacks telomerase, but instead uses retrotransposonsto maintain telomeres.
The hallmarks of aging are the types of biochemical changes that occur in all organisms that experience biological aging and lead to a progressive loss of physiological integrity, impaired function and, eventually, death. They were first listed in a landmark paper in 2013 [1] to conceptualize the essence of biological aging and its underlying ...