- May 15, 2012 at 10:45 pm #16493JoGoParticipant
I was just wondering if someone has a legit explanation of why cells age?
- May 15, 2012 at 10:57 pm #111107jonmoultonParticipant
"Why" is a difficult question for science to tackle. How do cells age? That question can get you loads of information. When and where do the changes associated with aging occur? Again, there is plenty of literature addressing that. What happens to cells as they age? Sure, again that is a common research topic and plenty has been done. "Why", however, is more a question for philosophers than for science — it’s not very testable (technically, hypotheses about "why" are often not falsifiable).
Try some keywords using the term "senescence" in Wikipedia, PubMed, etc. and you’ll find entries into the topic of aging. Generally though they won’t answer the "why" question.
- May 15, 2012 at 11:02 pm #111108JoGoParticipant
Sorry, what I meant to ask is HOW cells age. I’ve read lots of articles online but none seem to give an answer that is globally excepted. I was just curious if there is a globally accepted theory?
- May 16, 2012 at 2:04 am #111111plasmodesmata11Participant
Look up telomeres!
- May 16, 2012 at 2:49 pm #111121jonmoultonParticipant
Other useful search terms include:
lamin A, progerin
There are various factors that contribute to aging of a cell. I don’t think you’ll find a single switch that explains it all. An interesting topic in aging is the disease Hutchinson-Gilford progeria, which ties in with the Lamin A topic I mentioned above.
- May 19, 2012 at 11:13 pm #111162animusParticipant
Ooh, I can add to what plasmodesmata11 said about telomeres.
Telomeres are repeating (and I’m pretty sure, noncoding) sequences of DNA at the tips of chromosomes. As the cell repeatedly replicates itself, bits of the ends of the chromosome don’t copy, so the telomere part is giving the chromosomes leeway. Eventually, the telomere shortenings accumulate and will cut into actual coding DNA, leading to signs of aging. (Though I looked it up to double-check myself, and websites said that the bits that don’t copy don’t cut into the coding DNA—once it reaches the coding DNA, it makes the cell stop dividing. That sounds strange; I like what I learned, better.. hah)
Wikipedia actually has a nice list of theories about aging here:
- June 22, 2012 at 6:16 am #111646HasansalhiParticipant
As everybody said, look up for Telomeres!
Telomeres are sequences of the DNA that are added at the tips of chromosomes, and as a cell is passing through its division cycle, the DNA is replicated and the ends are shortened as a result of the END REPLICATION PROBLEM (read about this one, it will be useful to understand it). As these parts are shortened, at some point the ends will be almost near the coding DNA leading the cell to undergo apoptosis before the coding ends are cut as well!
Telomerase is an enzyme that adds telomeres to the ends of chromosomes. The problem is that telomerase exists only in the cancerous cells (and I don’t actually understand why) and germ cells. Therefore, because it doesn’t exist in the normal somatic cells, these cells will die at some point, and well, as you know, not all body’s tissues can regenerate, and so those which die will progress to show some aging symptoms. Take a skeletal muscle tissue for example, it doesn’t regenerate and as its cells die by aging, muscle weakness will result!
- July 17, 2012 at 7:29 am #111852citroenboomParticipant
And what about my precious E. coli! They do not contain telomers 🙂
They age because of damage by the environment, by dividing, DNA damage and that sort of things.
In Groningen University (The Netherlands) is some nice research going on about this topic (as I understood)
- July 19, 2012 at 2:47 am #111871oncolyticParticipant
Look at this article, reliability theory of aging, it seems to be a little more fundamental than just causative theories like free radicals, etc.
- July 19, 2012 at 3:23 am #111872david23Participantquote citroenboom:
Interesting thought, many years ago there were a few experiment about the regenerative abilities of bacteria cells. Basically they intentioned through heat, chemical, radiation etc etc induced damages to a few eColi colonies. examined them, and tagged a few cells/nucleotides, and cultured them for a few gens. Result, the later bacteria went on living normally. colonies grew.
- July 19, 2012 at 6:43 am #111874
Of course. Bacteria must survive. Technically every bacteria is old few billions of years.
- August 13, 2012 at 11:55 am #112085KileYeParticipant
I contend it is the metabolism that resulted in the aging of cells
- September 3, 2012 at 11:45 am #112230citroenboomParticipant
Still not all cells in a colony will grow. If I remember correctly from a presentation here some cells stop growing after a while and die. Or turn to ‘stand-by modus.
A complete colony contains so much cells that some can survive, but most will not. It is a matter of selection.
- September 12, 2012 at 2:25 am #112314david23Participantquote KileYe:
Yeah metabolism is a huge factor.
- September 23, 2012 at 4:55 am #112433tmbirkheadParticipant
I see a lot of comments on here about shortening telomeres causing aging. The telomeres are a bit more tricky than that.
Telomeres are indeed noncoding regions at the end of DNA that protect the rest of the DNA sort of like the hard part at the end of a shoe-string.
When the telomeres get too short, the DNA can become exposed and damaged. However, if telomeres are kept forever long, the increased risk of cancer outweighs any good of keeping the cell alive. Cancerous cells are only dangerous because they can keep the telomeres long enough to continually divide and make copies of the mutant onco genes (this is simplified–I know).
Further, I think it is certainly scientific to ask "Why" we age. The word, "Why", in this situation implies a cause and effect relationship. If such-in-such did or did not happen, then would the cells age.
The real problem is defining what aging is on a cellular level. We know what age looks like on a macroscopic level and we understand age chronologically, but the fact is, some people die from age-related illnesses at much shorter times in their lives than others. We might say that they aged more rapidly.
I did a research paper my sophomore year of college (last year) on the issue of aging and life rejuvenation theories.
There is a lot of buzz about SENS theory. And although I like SENS, I cannot say whether or not it is valid (as a lot of highly trained bio-gerontologists disagree over this). However, reading about the SENS plan to reverse aging will give you the 7 currently accepted basic reasons for why we age.
Let me know what you think
- October 11, 2012 at 4:42 am #112673
Interesting stuff on aging Tmbirkhead. Coq10, aceytyl carnitine, NADH stuff like that seems to be the way to go based on orthomolecular medicine (Linus Pauling, Abram Hoffer).
Both lived in to their 90’s and man they were still sharp as a razor as witnessed by these videos. Random interesting thing based on Peter Duesbergs book ‘Inventing the AIDS virus’ both him and Linus Pauling are the only 2 members of the national academy of science to have papers rejected for publishing (he says they could normally just skip the peer review and go straight to publishing) Dusberg for a paper on ‘HIV’ (and its lack of ever being proved to exist) and Linus Pauling for a paper on high dose Vit c and cancer.
- October 28, 2012 at 8:25 am #112792AstraSequiParticipant
Most or all of orthomolecular medicine is pseudoscience.
Also, every scientist gets papers rejected, no matter what their standing is – it’s a normal part of the peer review process.
- October 30, 2012 at 12:49 am #112800
Pseudoscience? You mean the neodarwinian religion that pervades EVERY area of science? You might want to learn some basic biology before citing essential cofactors (vitamins/minerals) as ‘pseudoscience’.
- October 30, 2012 at 8:00 am #112804
jinx: And you should not bring your evolution issues to every discussion if you want to continue discussing.
- October 30, 2012 at 10:58 am #112808
He referenced pseudoscience yes i understand thank you.
- October 30, 2012 at 10:59 am #112809
He called orthomolecular medicine to be pseudoscience. Why don’t you mention astrology?
- October 30, 2012 at 1:19 pm #112811
Yes and as i said learn some basic biochemistry. Astrology is not brainwashed into everyone on the planet at indoctrination camps (universities).
- November 1, 2012 at 3:01 pm #112832AstraSequiParticipant
…And I didn’t say that "essential vitamins/cofactors" don’t exist or don’t play a role in the body, which is what you’re implying that I said. As I’m sure you know, orthomolecular medicine involves the consumption of those compounds to an extent that is, to the best of our knowledge, far above the levels biochemically necessary to carry out their functions.
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