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The DNA damage theory of aging proposes that aging is a consequence ... In tissues composed of non- or infrequently replicating cells, DNA damage can accumulate with ...
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 network theory of aging provides a deeper look at the damage and repair processes at the cellular level and the ever changing balance between those processes. To fully understand the network theory as its applied to aging you must look at the different hierarchical elements of the theory as it pertains to aging.
Evidence supporting the theory started to crumble in the early 2000s. Mice with reduced expression of the mitochondrial antioxidant, SOD2, accumulated oxidative damage and developed cancer, but did not age faster. [33] Overexpression of antioxidants reduced cellular stress, but did not increase mouse life span.
All evolutionary theories of aging rest on the basic mechanisms that the force of natural selection declines with age. [19] [20] Mechanistic theories of aging can be divided into theories that propose aging is programmed, and damage accumulation theories, i.e. those that propose aging to be caused by specific molecular changes occurring over time.
The disposable soma theory of aging posits that there is a trade-off in resource allocation between somatic maintenance and reproductive investment.Too low an investment in self-repair would be evolutionarily unsound, as the organism would likely die before reproductive age.
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.
This ensures that the cell cannot enter the next stage of cell division unless the DNA damage is repaired. However, the p21 cells can trigger apoptosis. Apoptosis or programmed cell death is associated with gradual degradation of the immune system, skeletal muscle, and aging-associated malfunction. [32] Naked Mole Rat.