Dead cell

timojin said:
Wath happen to the DNA when the cell die
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It's still in there, but no longer directing protein synthesis.

Eventually the DNA breaks up and disappears. Even if the dead cells are quickly frozen, like those frozen dead mammoths that have been found in the Siberian arctic, the DNA quickly breaks up into lots of little fragments that make it difficult to reconstruct.

I believe that it's partly natural occurring DNAse enzymes in the cell that break up the DNA, and partly the effect of environmental conditions, particularly DNA's interactions with water. Living cells have natural DNA repair mechanisms, but these stop functioning when the cell dies, so the DNA degradation processes prevail.

This report suggests that DNA has a 'half-life' of 521 years.

http://www.nature.com/news/dna-has-a-521-year-half-life-1.11555
 
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Yazata said:
It's still in there, but no longer directing protein synthesis.

Eventually the DNA breaks up and disappears. Even if the dead cells are quickly frozen, like those frozen dead mammoths that have been found in the Siberian arctic, the DNA quickly breaks up into lots of little fragments that make it difficult to reconstruct.

I believe that it's partly natural occurring DNAse enzymes in the cell that break up the DNA, and partly the effect of environmental conditions, particularly DNA's interactions with water. Living cells have natural DNA repair mechanisms, but these stop functioning when the cell dies, so the DNA degradation processes prevail.

This report suggests that DNA has a 'half-life' of 521 years.

http://www.nature.com/news/dna-has-a-521-year-half-life-1.11555
Click to expand...

There is free floating DNA fragments and may be used for cancer analysis
Nucleosome positioning varies between cell types. By deep sequencing cell-free DNA (cfDNA), isolated from circulating blood plasma, we generated maps of genome-wide in vivo nucleosome occupancy and found that short cfDNA fragments harbor footprints of transcription factors. The cfDNA nucleosome occupancies correlate well with the nuclear architecture, gene structure, and expression observed in cells, suggesting that they could inform the cell type of origin. Nucleosome spacing inferred from cfDNA in healthy individuals correlates most strongly with epigenetic features of lymphoid and myeloid cells, consistent with hematopoietic cell death as the normal source of cfDNA. We build on this observation to show how nucleosome footprints can be used to infer cell types contributing to cfDNA in pathological states such as cancer. Since this strategy does not rely on genetic differences to distinguish between contributing tissues, it may enable the noninvasive monitoring of a much broader set of clinical conditions than currently possible.
http://www.cell.com/cell/abstract/S0092-8674(15)01569-X
 
timojin said:
Wath happen to the DNA when the cell die
Click to expand...

Eventually it will crack up, the molecule is not very stable outside of cells. The building blocks can be used as food for other cells. DNA is just a compound of amino acids which are quite common in nature, even in space some of them have been detected.
 
Edont Knoff said:
Eventually it will crack up, the molecule is not very stable outside of cells. The building blocks can be used as food for other cells. DNA is just a compound of amino acids which are quite common in nature, even in space some of them have been detected.
Click to expand...
You mean the Histone that encapsulate the DNA which is phosphate,deoxyribose and purine and pyrimidine.
 
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