DNA in a cell.

Frank O. Fackelmayer fof1 at chclu.chemie.uni-konstanz.de
Fri Apr 25 11:09:42 EST 1997


In article <1997Apr24.181506.2957 at wisipc.weizmann.ac.il>,
bcrubin at dapsas1.weizmann.ac.il (Rubin Eitan) wrote:

> I've worked out the same question for Tobacco, and got to a similar
number. However, if the cells are deviding you have up to 2 times more
DNA. 
> 
>    Eitan Rubin.
> 

Sure, you´re right. But if you want to be *that* correct, you will have to
know the percentage of cells in a population that has already gone through
S-phase. In normal cell culture (even more so in the body), most cells are
in G1, so they´re simply diploid, and the calculation is ok. 
In practice, it has turned out to be good for estimating the amount of DNA
you can prepare from a given number of cells, or, backwards, estimating
the number of cells from the amount of prepared DNA (sometimes VERY useful
to normalize assays).

Frank



> Labo TIM (tim at besancon.net) wrote:
> 
> : Frank O. Fackelmayer wrote:
> : > 
> : > In article <335E3721.18FC at besancon.net>, mail.besancon.net wrote:
> : > 
> : > > Hello,
> : > >
> : > > What is the quantity of genomic DNA in a human or mouse diploid cell;
> : > >
> : > > Thanks for your answer.
> : > >
> : > > CF
> : > 
> : > Hi,
> : > That´s easy to calculate....
> : > Let´s see:
> : > human genome is 3x10´9 base pairs * 2 for diploid= 6x10´9 bp
> : > 1 bp has a mass of approx. 660Da, so the genome is 6x10´9 * 660=
3.96x10´12Da
> : > 1 Dalton is 1.6735x10´-27kg or 1.6735x10´-15ng
> : > So the genome is 3.96x10´12 * 1.6735x10´-15ng= 6.627x10´-3ng
> : > 
> : > In other words, a single human cell has approx. 6.6x10-3ng DNA, or
> : > 1 million cells have 6.6micrograms of DNA
> : > 
> : > Hope this helps,
> : > Frank
> : > 
> : > --
> : > Dr. Frank O. Fackelmayer
> : > Division of Biology
> : > University of Konstanz
> : > D-78434 Konstanz
> : > Germany
> 
> : thanks for your help Franck
> 
> : CF
> 
> --
>        Eitan.  
> 
> 
> ======================================================================
> Eitan Rubin,
> Plant Genetics, Weizmann Inst of Science, Rehovot, Israel.  
> EMail: bcrubin at dapsas1.weizmann.ac.il
> Tel: (00972)-(8)9342421 Fax: (00972)-(8)9344181
> EitanR at BioMOO (http://bioinfo.weizmann.ac.il/BioMOO) - visit 
>                                             the GCG help desk
> ======================================================================

-- 
Dr. Frank O. Fackelmayer
Division of Biology
University of Konstanz
D-78434 Konstanz
Germany



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