Why do we die of old age?
I'm not looking for answers like 'the organs shut down,' or 'our body stops producing genes.' I'm looking for why that happens. We have the ability to stay alive forever by having our cells replaceing themselves all the time. So why does it stop?
- YuuLv 410 years agoFavorite Answer
Good question. A lot of people want to know the answer.
Yes, our cells divide and produce more cells to replace the ones that die. But this is all directed by the information stored in our DNA.
You can imagine that as the DNA gets copied over and over from the original template present in the egg+sperm, some mistakes might occur and the integrity of the genetic material will generally degrade. This is generally the basis of why our bodies start to fail on a cellular level (e.g. cancer). Even though we produce "new" cells, the DNA has already been copied over and over and subjected to external sources of damage such as UV radiation or harmful chemicals in the environment... think of making a copy of an original document on a traditional scanner, and repeating that over and over.
In mammals and other eukaryotes, DNA is arranged into structures called chromosomes, capped by a structural component called telomeres. These are kind of like tape on the end of a rope that keep it from coming undone and maintain it's structural integrity. The more times a cell has replicated, the shorter these telomeres become, because the cell can't replicate the DNA to the very end of the strand. Once the telomeres reach a certain "shortness" it signals the cell to die... effectively limiting the number of times a cell can divide. It is generally believed that this also has some effect on lifespan.
Also, some cells do not replicate, such as most neurons. So once you maintain damage to your brain it can't be easily repaired, especially considering the complexity of neural networks that you have formed over a lifetime. And since your brain controls many other bodily functions, once you lose that you're out of luck.
You can think about this on the level of the cell or the level of the organ or the level of the body as a functioning whole... but either way it all comes down to the same theme of a eventual reduction in the integrity of the system that can no longer be repaired.
- 4 years ago
We were not meant to grow old and die..suffer diseases etc...come to an age of maturity have grandchildren want to share our lives with our families and just die...No you are so sadly mistaken.I don't want to leave my children grandchildren,enjoy the sunshine the beautiful trees the ocean and awakening after a nights sleep to a new day.This is not what our Creator designed us for...He created us to live forever without disease and death...so sorry you are looking in the wrong direction,this is a very empty and unfeeling theory...:(
- 3 years ago
Old Age is not a Cause of Death. “Old age” is not truly a cause of death in and of itself. To “die of old age” means that someone has died naturally from an ailment associated with aging. The same usually goes for “dying of natural causes.”
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Every cell has DNA and it is consisted of two strands tightly woven around each other. The thing that prevents the two strands from breaking apart is called a telomeric cap (which is random nucleotide sequences called nonsense codons. Codon is a 3 sequence of nucleotides that codes for amino acids eg. CUU is a amino acid called proline . A nonsense codon is one that doesnt code for any amino acid production) Every time your cells divide a small sequence is lost there by reducing the stability of the cell's DNA (in layman's terms). This will eventually lead do most of Ur cells' DNA becoming unstable. And usually when a mistake occurs in DNA the cell will perform auto cytolysis (cell suicide) to prevent problems. So when you are old most of ur cells telomeric caps will be low and they are prone to die when they try to divide.. Whats really interesting about this theory is the impact it has on evolution (because this happens on both meiotic as well as mitotic divisions. which means that a species grows old too before it mutates.. but thats a different story)
- 10 years ago
1. Every time a cell duplicates its DNA a substance on the end of the DNA called telomere decreases. It's kind of like the plastic on the end of your shoelaces. When all the telomere is gone, the DNA can no longer make copies of itself. (Unfortunately trying to re-telomerize DNA results tumors)
2. We are not only made out of cells. Our cells, while we develop, and somewhat continuously throughout life, produce extracellular substances forming structures that we need such as bone and plasma. Although our bodies work at maintaining these substances and even tries to recycle worn out substances and recreate them, it is an imperfect process. Flaws accumulate. This is a primary cause of wrinkles.
3. DNA is really really great at making copies of itself, but flaws do creep in. Eventually these flaws accumulate and cause problems associated with aging, such as cancer.Source(s): College Biology, Genetics, Physiology, Anatomy, etc.
- Jenny ThomasLv 410 years ago
First of all, not all cells replicate in a relatively quick fashion. For example, some of the cells in your nervous system, which is necessary for survival. Also, nothing has the ability to stay alive forever. Why? Cellular decay. Aging. Maturation.
- 10 years ago
When your young, your cells replicate much faster. As you get old, cell replication becomes slower causing a decrease in the number of cells being replicated. Billions of cells die a day, but can you manage to fill the dead cells slot by replicating that fast?
- 10 years ago
every chromosome has a telomere. every time the cell divides the telomeres get shorter, until it tells the cell to stop dividing. If the telomere just allowed the cell to keep dividing, it would turn into a tumor, and you would get cancer. As you get older, your telomeres shut off and you don't get cancer, but cells stop dividing, and you die. That's how I understand it, not 100% sure though.
Our cells do replace themselves, but as we age, that ability slows and degrades, until finally we degrade faster than we rebuild. There's a lot of research going on worldwide to try to prevent the degeneration of our regenerative capacity.
- Anonymous5 years ago
We were designed by our creator to live forever. It is a spiritual reason why we die, not physical. Read Romans chapter 5, verse 12 of the Holy Scriptures. It will tell you why we all die. The Holy scriptures also tells us how we can live again after death. Read First Corinthians chapter 15, verse 22. Also we have the prospect of living forever, for all eternity! Read Psalms chapter 37, verse 29.