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
742 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
4k views

Why does evolution not make our life longer?

Why does evolution not make life longer for humans or any other species?
18
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1answer
498 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 ...
16
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1answer
302 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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434 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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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 ...
13
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4answers
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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 ...
13
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1answer
799 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 ...
12
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168 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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1k views

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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200 views

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 ...
9
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167 views

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 ...
7
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3answers
120 views

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?
6
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1answer
7k views

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 ...
6
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3answers
164 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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3answers
523 views

Is there any kind of immortality in plants?

I asked a question about immortality of hydra and leaned good things about senescence. Now I like to know about immortality signs in plants. If there is some kind of immortality in plants its process ...
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2answers
363 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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342 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 ...
6
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1answer
60 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
516 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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1answer
190 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 ...
5
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1answer
193 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 ...
5
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1answer
147 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, ...
5
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1answer
99 views

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 ...
5
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1answer
78 views

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, ...
4
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1answer
947 views

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 ...
4
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2answers
128 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 ...
4
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1answer
95 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 ...
4
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2answers
56 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
71 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 ...
4
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1answer
191 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 ...
4
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1answer
159 views

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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RHEB senses amino acids in order to recruit mTOR. Do we know if RHEB is more sensitive to some amino acids (like methionine) than other amino acids?

See http://www.ncbi.nlm.nih.gov/pubmed/21157483 for the full paper describing the process of how RHEB recruits mTOR. We also discussed this in Matt Kaeberlein's class yesterday and I posed this ...
3
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1answer
65 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 ...
3
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2answers
599 views

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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1answer
69 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 ...
3
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2answers
56 views

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
40 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
413 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 ...
3
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2answers
206 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 ...
3
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0answers
24 views

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
78 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.
2
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2answers
60 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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1answer
61 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 ...
2
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1answer
67 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 ...
2
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1answer
127 views

What are the effects of combining rapamycin with dietary restriction?

Are the effects additive or subadditive? In many ways, rapamycin acts like a CR mimetic, but even CR can only go so far.
2
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0answers
24 views

How can stem cells be counted in body?

In the study of supercentenarian woman here, it was found that all her blood cells are formed from only two stem cells (ancestor stem cells). How scientists can distinguish cell ancestors? Aren't ...
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Source of information on the evolution of aging/senescence

Do you know a good review (published peer-reviewed or an online course or whatever) that offers a good overview of all hypothesis explaining the various patterns linked with aging? I'd like this ...