The process of biological aging or the state of an organism being biologically old.

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Do bacteria die of old age?

I know that the cells of mammals at least stop dividing when they are old, and then die a programmed cell death. Then other cells have to replace them. But in a bacterial colony, each cell ...
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5answers
885 views

Why do we age? or Do we have a theory of senescence?

There seem to be a number of ideas about why we age. Hypotheses include the gradual accumulation of cell metabolic products affecting organism function and the reduction of telomere length during cell ...
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7answers
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Why does evolution not make our life longer?

Why does evolution not make life longer for humans or any other species?
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538 views

Do trees age on a microscopic level?

Most animals age via at least two mechinisms: at a "macroscopic" level, basically wear and tear to the point where (on evolutionary time scales) it's more genetically advantageous to optimize for ...
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326 views

Why does regular exercise increase brain volume?

It has been shown in several studies that regular aerobic exercise increases brain volume in aging humans. The changes were observed in hippocampus and were correlated with dramatic reduction of ...
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Is there an advantage to linear chromosomes?

The DNA copying enzymes have a hard time working to the end of a chromosome. For circular chromosomes this is not a problem, since there is not a sharp 'end'. However, for a linear chromosome, without ...
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505 views

Why do some trees have a life span, while some don't?

I have heard that there is no limit on the growth of trees, but then why do some trees, such as boxelders and poplars, tend to live shorter than redwoods, for example? Some advertisements for improved ...
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Why is the Hydra Biologically Immortal?

I have heard that the Hydra organism is biologically immortal (later I found that there are more immortal organisms). Now I know that its immortality is related to its telomerase. The thing is that we ...
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906 views

Are human bodies programmed to die?

Following from this question: What is the evolutionary advantage of death?: Is there any evidence that human bodies have systemic self-destruction built into their developmental program? I'm not ...
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208 views

Have any mutations or genetic loci been associated with exceptional longevity in humans?

Individuals that avoid age-related diseases into later life are known as 'exceptional survivors', and have increased longevity compared to their 'controls' (those that were born at a similar time, yet ...
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Does current evidence support the use of resveratrol as an anti-ageing drug?

A while back there was a lot of noise about resveratrol, a naturally occurring phenol which was touted as a potential anti-aging drug due to its role in regulating the SIRT 1 gene. A number of studies ...
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Why does hair turn grey or white, and why does it happen later for some?

The question is pretty simple: what is happening molecularly when hair turns grey or white? I would imagine that it is due to the lack of a particular compound. I'm also interested in why some ...
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How are new people created from the DNA of an aged person. i.e. Why are we young?

The question "why do we age" has been asked numerous times. But why are we young? The cells of the adult human being are an age (time>0), but how can old cells create new cells that are younger than ...
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How does the NAD+/NADH ratio affect lifespan in vertebrates?

Here's the proximate physical implication of the ratio (from the Wikipedia article on NADH). The balance between the oxidized and reduced forms of nicotinamide adenine dinucleotide is called the ...
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Free Radicals for aging

From my understanding free radicals play a slight role in ageing. In what ways are they so damaging, and can a restricted diet reduce production of free radicals?
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1k views

Can human organs be transplanted indefinitely?

I watched this movie, where they rented hearts to people for a year. I wonder if it is possible to transplant a heart indefinitely from person to person, or does the heart have a lifetime? So, do ...
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Do crocodiles age?

I was watching a talk by Michio Kaku and he mentioned that crocodiles (or possibly alligators, I forget offhand) don't actually age -- they can die, but they essentially go through no aging process ...
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168 views

What reasons allow for women to outlive men?

It is a well-known fact that women tend to outlive men. I often hear people unscientifically stating that men generally generally die younger because of the higher stress encountered in their work ...
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608 views

Is there any kind of immortality in plants?

I asked a question about immortality of hydra and learned good things about senescence. Now I would like to know about immortality in plants, if there is some kind of immortality in plants and how ...
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387 views

Do immortal organisms exist?

Do organisms exist that are able to live indefinitely if they are not killed by external factors? Under external factors I would consider things like predators and natural disaster but not illness by ...
6
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371 views

Why are beta-galactosidase proteins overexpressed in senescent cells?

Wikipedia explains that it's a hypothetical hydrolase enzyme that catalyzes the hydrolysis of β-galactosides into monosaccharides only in senescent cells. I'm just wondering - what causes it to be ...
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1answer
63 views

How well supported is the hypothesis that aging is mainly caused by the number of mutations in tissues?

I heard the hypothesis, that the (main) reason of aging is the increasing number of mutations in body tissues. The higher the number of mutations is, the older tissue is. Is this true? And how well ...
6
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1answer
559 views

Exercise causes number of cell divisions to approach Hayflick limit faster? And hence shorten life expectancy?

A world class athlete spends a lot of time performing intense exercises. Correct me if I'm wrong, but I assume that these intense exercises causes significant damage to the athlete's cells, but with ...
5
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199 views

What evolutionary pressures pushed Galápagos tortoises to mature so slowly and live so long?

I read that they take up to 40 years (in the wild) to reach the age of reproduction and are thought to live over 100 years, with one in captivity reaching over 170 years. Can someone explain in ...
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216 views

Why isn't the p16-INK4a gene involved in apoptosis expressed in heart or liver tissues?

New York Times article explains how killing p16-INK4a positive senescent cells can help keep the surrounding cells vigorous. So here's my question: why is p16-INK4a expressed in most cells other than ...
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148 views

Does AMP/ATP ratio affect lifespan in vertebrates?

The reference below says that a higher AMP/ATP ratio is associated with lower lifespan in C. elegans. Is this finding also generalizable to vertebrates as well? Reference: Apfeld, J., O’Connor, ...
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In what ways, if any, does administration of rapamycin *not* mimic calorie restriction?

Numerous sources like this say that rapamycin increases lifespan. And mTOR antagonism appears to be a large part of this (mTOR antagonism also appears to be a large part of calorie restriction's ...
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Why would we overexpress Sir2 by overexpressing its hypomorph (dSir2-EP2300) in C. elegans?

Can't we just overexpress regular Sir2 in the paper? Rather than overexpress a reduced-function gene? The paper is Burnett C, Valentini S, Cabreiro F, Goss M, Somogyvári M, Piper MD, Hoddinott M, ...
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How do caspase proteins kill a cell?

Wikipedia just says... The active effector caspases then proteolytically degrade a host of intracellular proteins to carry out the cell death program. Okay, but what parts of the cell do they ...
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2answers
134 views

Is solving cancer required in order to avoid aging?

When the telomerase enzyme is not active the telomere shortens every time the cell duplicates leading to a reproductive limit (Hayflicks limit). On one hand this is a believed reason for aging. On the ...
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101 views

Difference In Telomeres Between A Thale Cress Plant And A Methuselah Tree

From what I have read and understood telomeres cap off how many times a cell can divide before it can no longer divide and that is what causes aging. A thale cress plant apparently has a life cycle ...
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71 views

Does increased physical activity increase the rate of cell division?

Ever since learning that the shortening of telomeres is linked to aging I've tried to figure out what causes cells to divide, and if it's possible to slow down the rate of cell division through life ...
4
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1answer
76 views

During human ageing, which immune cell sub-types are most affected?

It is now well established that human ageing is accompanied by an increase in systemic, low-grade (chronic) inflammation, sometimes termed inflammaging (Franceschi, 2007). This is in part due to more ...
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255 views

How much does the Hayflick limit/telomere length vary across taxa and within humans?

Since they seem to be quite connected, I'm curious if anyone knows of research comparing the Hayflick limit (and presumably by extension telomere length) between different taxa. I've heard the ...
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Is cell senescence in culture comparable to that in vivo?

A cell is 'senescent' when is has permanently left the cell-cycle. This can be caused by stresses, or by reaching the 'Hayflick limit' (the cell has reached its replicative lifespan, as defined by its ...
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67 views

Do people with gout live longer?

Antioxidants reduce damage to tissue (by scavenging the free radicals) and thus may reduce ageing.It is known that Uric acid is a very good antioxidant. People with gout have excess accumulation of ...
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2answers
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Cell life: division for immortality or reproduction with aging

Are the two cells that are derived from one cell, ‘twin sisters’ or a ‘mother and a daughter’? In other words, can a cell really be divided to live an "immortal" life or is cell reproduction the ...
3
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82 views

Hibernation, Metabolism and Aging

People are beginning to seriously research space travel applications of therapeutic hypothermia, specifically for reducing metabolism and stress on humans traveling to Mars. It seems that as you ...
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In practice, do fishes die from old age?

I was watching sea birds eating fishes and wondered if fishes actually died from old age, or if they are all eaten before this can happen? I reckon some big predator fishes must be able to live long ...
3
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1answer
43 views

How do mosquitoes maintain telomere length?

While the vast majority of eukaryotic organisms maintain their chromosome ends (telomeres) via telomerase, an enzyme system that generates short, tandem repeats on the ends of chromosomes, other ...
3
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1answer
433 views

Could inhibition of progerin formation slow the rate at which a body ages?

According to wikipedia, progerin is activated in senescent cells. The protein itself is known to be the cause of a rare affliction 'progeria' - a disease marked by accelerated aging of the body. This ...
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221 views

Does the speed of electrical impulses through neurones decrease with age?

From what I read on the NatGeo app, it stated that the speed of the electrical impulses that are sent by a neurone will be approximately 332 kilometers per hour. Will the speed of this electrical ...
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Circulating factors affecting human health/longevity

Circulating factors present in young mice have been shown to promote rejuvenation of aged mice, suggesting that tissues have inherent capabilities to regenerate, and circulating factors may be ...
3
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Effect of Aging on SA node's sympathetic fibers

I am trying to understand the effect of aging on the sympathetic fibers of SA node. I know that aging shifts the vagal curve to left in frequency due to aging. However, I am interested if aging has ...
3
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0answers
81 views

Papers linking telomeres and aging [closed]

I'm currently writing a piece of work about telomeres and aging, and wondered if you could share some good papers you've either read or know of.
3
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1answer
44 views

Do we know if RHEB is more sensitive to some amino acids than other amino acids?

RHEB (Ras homolog enriched in brain) senses amino acid levels in order to recruit mTOR. See this review describing the process of how RHEB recruits mTOR. So does RHEB have differential selectivity ...
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2answers
73 views

How does the telomere repeat sequence vary in Eukaryotes?

Question: How does the telomeric repeating sequence vary in non-vertebrate Eukaryotes? If you know the repeating sequence of a given species I would appreciate hearing it. Background: Telomerase is ...
2
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2answers
105 views

Do couples having children later in life act as an evolutionary mechanism?

Ok, this may be just wild nonsense and I have to warn that my knowledge on the subject is limited. I was reading about how in some countries people choose to have children later in life. After that ...
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1answer
63 views

Age-associated neurodegenerative diseases

Age-associated neurodegenerative diseases encompass Alzheimer's Disease and Parkinson's Disease. What other neurodegenerative diseases could be described as age-associated? Multiple Sclerosis? Brain ...
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87 views

Senescence, immortality and evolution?

Many have heard about the fabled "immortal" jellyfish, Turritopsis dohrnii, which doesn't die from aging (senescence) and can revert the aging process indefinitely. It is rather remarkable that only ...