Cell Replication limit and logic

[Pup Shepard]

I had read that human cell have a limited number of times before replication start becoming difficult. Logically, this can not be entirely true. Sexual reproduction has been around for many generations requiring the replication of cells of each human in the entire tree. Looking another way, sex cells replicate rapidly. When two cells mix and form a child, those cell still have all the previous replications since the parents birth. As we can see, we have an unbroken line of cells that have been replicating for thousands of years. The idea that people age because cells slowly lose the ability to replicate seems illogical. If cells do have a limit, we have to assume the body has the means to manufacture new cells by a process that does not involve cell replication. If this process exists, it is quite possible, that it can be used to prevent death from old age.

[Volbet]

I thought stuff like this was taught in middle school biology. 

No, it's not "illogical" that human cells becomne harder and harder to reproduce, since the mechanism that guides the reproduction of regular body cells is different from the mechanism that guides reproduction of sex cells (sperm cells and egg cells).

Look up the difference between meiosis and mitosis. Therein lies your answer.

 

Simply put, meiosis would be way too slow of a process to replace the cells in the human body, so the faster (and more fault prone) mitosis process is used. 

 

This difference is also why a lot of the early cloned animals died at a very young age. 

Look up the life spand of Dolly if you are curious. 

[Kajornkeat]

I believe it's something to do with "telomere" regions of chromosomes. You can look it up for its function. After cell goes through lots of Mitosis (body cell replication),  telomere will degrade and eventually chromosome damage will occur which leads to cell inability to correctly replicate (in most cases) and cell death program (apoptosis) will be triggered to prevent faulty cell duplication. In some cases, DNA/chromosome damage might cause the cells to gain super power to infinitely replicate and turn into tumor/cancer instead.

 

If I'm not mistaken, during meiosis, fertilization and embryonic development, there is some kind of mechanism that help cell make/lengthen telomere region of chromosome. 

 

There is some study try to understand telomere repairing + elongation pathway/mechanism  and turn that knowledge into Anti-aging drug. Interesting topic imo. 

 

[AshleyAshes]

4 hours ago, rubberpuppy said:

I had read that human cell have a limited number of times before replication start becoming difficult. Logically, this can not be entirely true. Sexual reproduction has been around for many generations requiring the replication of cells of each human in the entire tree. Looking another way, sex cells replicate rapidly. When two cells mix and form a child, those cell still have all the previous replications since the parents birth. As we can see, we have an unbroken line of cells that have been replicating for thousands of years. The idea that people age because cells slowly lose the ability to replicate seems illogical. If cells do have a limit, we have to assume the body has the means to manufacture new cells by a process that does not involve cell replication. If this process exists, it is quite possible, that it can be used to prevent death from old age.

There's two possible scenarios here:

 

1) You have discovered that humans are secretly immortal, using an exceptionally simple observation that any child could make.

 

2) You fail to understand the topic beyond the most basic level, so much so, you believe that you can make a compelling argument rather than assuming that you must not be fully understanding key elements.

 

...Guess which scenario this is.

 

In short, not all human cell are subject to the Hayflick limit or experience different Hayflick limits.  This includes stem cells, some cancer cells, and others.

 

Pro tip: If you think that you came up with something brilliant and obvious that scientist the world over, over the span of decades, must have missed, it's most likely that you just know nothing about the topic at hand.

[Nicnac]

Was almost triggered to write an essay but then read your posts first 

2 hours ago, AshleyAshes said:

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4 hours ago, Volbet said:

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Excellent work gentlemen!

[captain_to_fire]

7 hours ago, rubberpuppy said:

If this process exists, it is quite possible, that it can be used to prevent death from old age.

Are you looking about the process of DNA capping and telomeres? 

[Zodiark1593]

10 hours ago, Kajornkeat said:

I believe it's something to do with "telomere" regions of chromosomes. You can look it up for its function. After cell goes through lots of Mitosis (body cell replication),  telomere will degrade and eventually chromosome damage will occur which leads to cell inability to correctly replicate (in most cases) and cell death program (apoptosis) will be triggered to prevent faulty cell duplication. In some cases, DNA/chromosome damage might cause the cells to gain super power to infinitely replicate and turn into tumor/cancer instead.

 

If I'm not mistaken, during meiosis, fertilization and embryonic development, there is some kind of mechanism that help cell make/lengthen telomere region of chromosome. 

 

There is some study try to understand telomere repairing + elongation pathway/mechanism  and turn that knowledge into Anti-aging drug. Interesting topic imo. 

 

The way I see it is that whenever a cell duplicates, there is a small chance that some portion of the DNA becomes corrupted. With some forms of corruption, the programmed cell death may be interrupted, leaving the immune system to recognize the corrupted cell and destroy it. Failing this, cancer may be the result.

 

Given the innumerable quantity of cells within a body, I have to wonder how often corruption actually occurs, damaging, or not.

[Kajornkeat]

10 hours ago, Zodiark1593 said:

Given the innumerable quantity of cells within a body, I have to wonder how often corruption actually occurs, damaging, or not.

It's truly amazing how nature deals with these type of issue and make us survive through out all these time.  

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2906700/

 

I found this article in NCBI. Might be a bit old but nicely written and easy to understand.

 

Pretty much tens of thousands DNA lesion happen every day and somehow through the magic of DNA repair mechanism, we don't have to wake up in the morning and discover a new cancer in/on our body everyday.