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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 ...
Shell Oil, Emeryville, California; University of Nebraska. Denham Harman (February 14, 1916 – November 25, 2014) was an American medical academic who latterly served as professor emeritus at the University of Nebraska Medical Center. [1][2][3] Harman is known as the " father of the free radical theory of aging ". [2][3]
The free-radical theory of aging proposes that this damage cumulatively degrades the biological function of cells and impacts the process of aging. [17] The idea that free radicals are toxic agents was first proposed by Rebeca Gerschman and colleagues in 1945, [18] but came to prominence in 1956, when Denham Harman proposed the free-radical ...
Aubrey David Nicholas Jasper de Grey (/ dəˈɡreɪ /; born 20 April 1963) is an English biomedical gerontologist. He is the author of The Mitochondrial Free Radical Theory of Aging (1999) and co-author of Ending Aging (2007). De Grey is known for his view that medical technology may enable human beings alive today not to die from age-related ...
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 ...
Ageing (or aging in American English) is the process of becoming older. The term refers mainly to humans, many other animals, and fungi, whereas for example, bacteria, perennial plants and some simple animals are potentially biologically immortal. [ 1 ] In a broader sense, ageing can refer to single cells within an organism which have ceased ...
The Hayflick limit is the limit on cell replication imposed by the shortening of telomeres with each division. This end stage is known as cellular senescence. The Hayflick limit has been found to correlate with the length of the telomeric region at the end of chromosomes. During the process of DNA replication of a chromosome, small segments of ...
Reactive oxygen species (ROS) with the potential to cause cellular damage are produced along with the release of energy. ROS can damage lipids, DNA, RNA, and proteins, which, in theory, contributes to the physiology of aging. ROS are produced as a normal product of cellular metabolism.