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Germ-line cells

  1. Apr 4, 2008 #1
    Do germ line cells accumulate DNA Damage like the rest of the body? I've heard things about them that make them seem to have very different characteristics to the rest of the body. Ie could germ line cells, or anything, contain your original DNA when you're like 50 or 100, or would the only DNA you have at that point be damaged, non original DNA

    Also could somebody list all the believed causes of aging? DNA damage is considered one of the main contributors right?

    Also...if you made a clone of yourself when you were like 50...wouldn't the clone have damaged DNA as well, because you'd be using your damaged DNA to clone it?
    Last edited: Apr 4, 2008
  2. jcsd
  3. Apr 6, 2008 #2
    Of course mutations gather in germ-line cells.
  4. Apr 9, 2008 #3
    Can you not fix UV damage in a cell outside the body with the photolyse enzyme? and despite the fact that this enzyme fixes uv damage, you can't introduce it into a human body, can you?
  5. Apr 10, 2008 #4
    But isn't UV damage one of the main causes of damaged DNA. As far as my current knowledge goes to, our cells have an enzyme called DNA Polymerase III which proofreads the newly formed DNA strands for any errors and then fixes them through exonuclease.

    I am only in my first year of university, so my knowledge is pretty basic still. BTW bioquest, as clouded said DNA damages or mutations do occur in germ line cells because without them I doubt we would have many errors or defects in child births (that is because sex cells are a form of germ cells).
  6. Apr 10, 2008 #5


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    UV is not necessarily the main cause of DNA damaged especially for cells that are underneath layers of cells. DNA polymerase is, more often than not, the main source of errors introduction into DNA sequences. Other source of mutation/damage would be reactive oxygen species that are produce by respiration and normal metabolism.
  7. Apr 10, 2008 #6
    Photolayse is very, very good at repairing UV damage I think?...is there an enzyme or anything like that that is extremely good at repairing oxidative damage?

    Also do you think it's possible to fix the UV damage in a cell outside of the cell, or do you think that would be extremely difficult to do?
  8. Apr 10, 2008 #7
    There are likely many factors to aging. Build-up of free radicals, shortening of telomeres, DNA damage, just to name a few. There are probably hundreds of other causes we have yet to discover as well.

    Perhaps someday in the distant future, scientists will be able to create a test-tube human baby that has all the proper programming in place to not exhibit any aging after reaching adulthood, but you might as well face the fact that YOU are doomed to age and die just like the rest of us. ;}
  9. Apr 10, 2008 #8
    Would increasing the levels of natural antioxidents in our body help with free radical DNA damage? Can antioxidents reverse free radical DNA damage? Is there an enzyme like photolayse which really helps with DNA damage?

    Yah but bio knowledge is still good to get. and this anti aging knowledge stuff appears to be trendy/sexy so :p
  10. Apr 10, 2008 #9
    Yeah, there are many things we could do to "help", but the end result will always just be delaying the inevitable. Maybe you could get a few extra years here and there with different therapies, but nobody lives forever. :) (...which is a GOOD thing because our population growth is way out of control as it is! If we gained immortality we would most certainly destroy ourselves.)

    The very nature of our life-cycle biology is a hard-wired "program" to get old and die. The only way to get around this is to create a new "program" and that could only be done with a new life just starting out as a single cell.
  11. Apr 17, 2008 #10
    They said my password was outdated and needed to be changed/the password was too old, and I don't remember if I changed it but if I did I don't remember it

    Here's my question...are free radicals necessary for cell signaling and for what else (And are they necessary for that in the brain as well as the rest of the body, and if so in what ways)..if so why...are there any alternative to free radicals that can be used as a substitute and can do the positive things that free radicals do, such as synthetic free radicals and why or why not for example, if free radicals are necessary for cell death signaling, couldn't the white blood cells of cancer resistant people theoretically stop cell population from growing out of control too, if they stop cancer?

    Thanks, that is pretty much my last question
  12. Apr 17, 2008 #11
    Um, never mind ignore the above..except for the question of what other than antioxidents could be used to protect dna from free radical/oxidative damage
    Last edited: Apr 17, 2008
  13. Apr 18, 2008 #12
    I also can't edit posts for some reason

    I have a better understanding of free radicals now...but why is them being in the brain necessary for survival? I understand they're necessary in the rest of the body for survival. My friend whose taken like 5 years of molecular biology in university either misunderstood my question or forgot the answer to why they're necessary for survival in the brain
  14. Apr 18, 2008 #13

    Really...I do not get that impression in the slightest. :P

    Too many free radicals is generally a bad and destructive thing to have around.

    Maybe you should try looking stuff up online that you don't understand instead of repeatedly "shooting from the hip" ... as they say. :) Then you will be able to ask more coherent questions and actually understand what you are asking...(just a suggestion).

    (I am assuming this is Bioquest under a new name)
  15. Apr 18, 2008 #14
    But I just talked to someone, and they said free radicals were necessary for survival. Wikipedia says that they are necessary for survival too:
    Free radicals play an important role in a number of biological processes, some of which are necessary for life, such as the intracellular killing of bacteria by neutrophil granulocytes.

    What I was wondering is, are they necessary for survival in the brain and if so for what reasons?

    I am bioquest but it said I had to change my password, and yah, anyways I have to go take my dog out..but hopefully somebody could answer the question about why they are necessary for survival in the brain, if they are. I mean I wasn't saying too many free radicals were good, just that their existence is apparently necessary?
    Last edited: Apr 18, 2008
  16. Apr 21, 2008 #15
    Not all oxidative modifcations to cells are bad right? Are some necessary for survival?

    Also theoretically, how long could someone live in a bubble for if there was never a leakage? indefinetly? why/why not? thanks
  17. Apr 21, 2008 #16


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    Perhaps I can shed some light on this discussion by explaining why free radicals are necessary in biology.

    Free radicals are both useful and harmful in biology because of their reactivity. Their utility comes from the fact that free radicals can perform reactions that are otherwise very difficult to accomplish. Therefore, some enzymes make use of free radicals for just that purpose, to perform difficult chemistry. In these cases, it may be that free radical chemistry is the only way in which a cell could perform these reactions under physiological conditions.

    One vitamin, cobalamin or vitamin B12, plays an important role in generating free radicals for use in these reactions. The radicals generated by cobalamin are essential for enzymes involved in the metabolism of fats and in methyltransferase reactions (essential for many biochemical processes, including the synthesis of thymidine nucleotides). Another enzyme that uses free radicals is ribonucleotide reductase, an enzyme required for the synthesis of the deoxyribonucleotides that make up our DNA.

    (The final example of the beneficial role of free radicals in biology is nitric oxide, a free radical gas molecule that acts as a signaling molecule. Less is understood about why this needs to be a free radical.)

    In all of these cases, the generation, transfer, and quencing of the free radical is highly regulated by the enzymes involved such that the free radical reacts only with the desired substrate. For example, ribonucleotide reductase sequesters its free radical group in the interior of the protein, far away from the enzyme active site. Only when the enzyme has bound its substrate will the enzyme transfer this radical to the active site.

    Now, harmful free radicals are ones generated as side-products of other reactions (e.g. in the electron transport chain). Because the production, transfer, and quenching of these radicals is not regulated at all, their reactivity allows them to react with and destroy many required components of the cell.
  18. Apr 21, 2008 #17
    Here's my question...I asked somebody about this and they said this:
    1) Even if somebody makes a chip..to find the oxidative damage on any gene..the question always is...which oxidative DNA modification is GROWTH and Maturation related and what is aging related

    if you got rid of all the oxidative DNA modifications for growth and maturation (Obviously this isn't possible to do, but if it was) would you die, or would you just have your growth stunted?
  19. Apr 22, 2008 #18

    Is the photolyase gene/enzyme connected to photosynthesis? ie how big of a contributor/cause of photosynthesis is this?

    Also, blood doesn't contain DNA, right?
  20. Apr 24, 2008 #19
    k I guess what I'm wondering is, if you had the technology to be able to do this, could you replace genes in a cell one at a time or all at once, with identical healthy non defective DNA? if you had the DNA and the technology to do that? What obstacles would there be to doing that aside from the method of drug delivery (ie. nanoparticles) and things like that not being efficient enough? Would you be able to match the unhealthy genes with the healthy genes- ie find the healthy copy of each gene? (if you had the original DNA/healthy DNA) or would that be impossible? Would a cell with mismatched genes die? thanks
  21. Apr 24, 2008 #20
    I mean, can you remove genes from cells without killing the cells? how often can you do this/how successful is it?
  22. Apr 24, 2008 #21
    k I can't edit/delete posts, I guess my only question now after talking to my bio friend is:

    Do all animals that breathe get/keep problematic oxidative DNA damage?

    Are too problems caused by DNA damage unfixable (the problems, not the DNA damage itself) and would thus result in eventual death?
  23. Apr 26, 2008 #22
    has every cell recieved some sort of oxidative DNA damage? How often does Oxidative DNA damage occur?
  24. Apr 26, 2008 #23
    I mean, couldn't you design a computer chip or something to view all the genes in each cell, so you could see which cells had the most oxidative DNA damage and kill those cells, or fix them (I guess that wouldn't be possible though) or something?
  25. Apr 26, 2008 #24
    also, my friend said that cells need some genetic material to survive, ie you can't just take it all out and replace it all. Is this true with neuron/brain cells?
  26. Apr 26, 2008 #25
    My only question now is: (i can't edit posts)

    I mean are you sure that, theoretically, there is nothing (no chemical or anything, once introduced into the system) that could reverse oxidative DNA damage/stop the effects of oxidative DNA damage? (if it reached the DNA)
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