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Correct Answer: free-radical theory
the correct answer to the question is the **free-radical theory**. this theory is one of the biological explanations for the aging process in humans and other organisms.
the free-radical theory of aging was first proposed by denham harman in the 1950s. it suggests that organisms age because cells accumulate free radical damage over time. free radicals are unstable molecules with unpaired electrons, created as byproducts during normal cellular metabolism. they can also be introduced through external sources such as tobacco smoke, radiation, and pollution.
free radicals are highly reactive due to their unpaired electrons, and they can interact with cellular components like dna, proteins, and cell membranes, causing oxidative stress. this interaction is a form of oxidation, a chemical reaction where electrons are transferred between molecules, potentially leading to significant cellular damage.
the damage caused by oxidative stress affects critical aspects of cell function. for instance, when free radicals damage dna, it can lead to mutations and interfere with the process of dna replication, crucial for cell division and repair. damage to cell membranes disrupts cellular integrity, affecting the cell’s ability to function normally.
over time, the cumulative damage from oxidative stress can contribute to the decline in physiological function observed during aging, as well as the development of age-related diseases such as alzheimer’s disease, parkinson’s disease, and various forms of cancer.
the free-radical theory has been influential in guiding research into aging and the development of dietary and lifestyle habits that might mitigate aging. for instance, antioxidants, which are substances that can neutralize free radicals by donating electrons without becoming destabilized themselves, are often recommended to help combat oxidative stress. these can be found in many fruits and vegetables, and their increased consumption is frequently suggested as a method to help slow down the aging process.
while the free-radical theory remains a prominent explanation for aging, it is important to note that aging is a complex, multifactorial process likely influenced by various biological, sociological, and psychological factors. other theories of aging, such as the telomere shortening theory, the wear-and-tear theory, and the hormonal regulation theory, also contribute to our understanding of this intricate process.
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