Search results
Results from the WOW.Com Content Network
Cellular senescence is a phenomenon characterized by the cessation of cell division. [ 1 ][ 2 ][ 3 ] In their experiments during the early 1960s, Leonard Hayflick and Paul Moorhead found that normal human fetal fibroblasts in culture reach a maximum of approximately 50 cell population doublings before becoming senescent. [ 4 ][ 5 ][ 6 ] This ...
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 ...
This is called cellular senescence. Senescence can be induced by several factors, including telomere shortening, [37] DNA damage [38] and stress. Since the immune system is programmed to seek out and eliminate senescent cells, [39] it might be that senescence is one way for the body to rid itself of cells damaged beyond repair.
As the cell divides, the telomeres on the ends of chromosomes shorten. 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.
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 ...
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 ...
DNA damage resulting in multiple broken chromosomes. DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. [ 1 ] In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA damage, resulting in tens of thousands of ...
Life history theory. Life history theory (LHT) is an analytical framework [1] designed to study the diversity of life history strategies used by different organisms throughout the world, as well as the causes and results of the variation in their life cycles. [2] It is a theory of biological evolution that seeks to explain aspects of organisms ...