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The definition of "longest-living" used in this article considers only the observed or estimated length of an individual organism's natural lifespan – that is, the duration of time between its birth or conception, or the earliest emergence of its identity as an individual organism, and its death – and does not consider other conceivable ...
Rather than protecting cells from aging, long telomeres help cells with age-related mutations last longer. [13] This problem prepares the conditions for the occurrence of various types of cancer, and people with longer cell telomeres showed more signs of suffering from types of cancer such as Melanoma and Lymphoma. [13]
Among the most commonly used cell lines are HeLa and Jurkat, both of which are immortalized cancer cell lines. [4] These cells have been and still are widely used in biological research such as creation of the polio vaccine, [5] sex hormone steroid research, [6] and cell metabolism. [7] Embryonic stem cells and germ cells have also been ...
HeLa cells, like other cell lines, are termed "immortal" because they can divide an unlimited number of times in a laboratory cell culture plate, as long as fundamental cell survival conditions are met (i.e. being maintained and sustained in a suitable environment).
This close relationship to the stem cell region suggests that Paneth cells are important in defending the gland stem cells from microbial damage, [4] although their function is not entirely known. [2] Furthermore, among the four aforementioned intestinal cell lineages, Paneth cells live the longest (approximately 57 days). [6]
The niche for long-lived plasma cells is a subject of ongoing research, and while some aspects are understood, many questions remain. LLPCs are not inherently long-lived, and their survival relies on accessing specific pro-survival niches in the bone marrow, secondary lymphoid organs, mucosal tissues, and sites of inflammation.
The typical normal human fetal cell will divide between 50 and 70 times before experiencing senescence. 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 initial development of the cell marked the passage from prebiotic chemistry to partitioned units resembling modern cells. The final transition to living entities that fulfill all the definitions of modern cells depended on the ability to evolve effectively by natural selection. This transition has been called the Darwinian transition.