Molar concentration of human DNA

Answer 1

"Human cells vary in size and volume. DNA is fixed in its size. That makes it kind of hard (like impossible) to state a concentration for DNA. Only a range can be given, and that information has little to no practical value and even less meaning."

Cell size and volume have nothing to do with the absolute amount of substance measured in mol, which is what the ill written question probably meant to ask.

Each human cell contain a genome of about 6*10e9 bp. One mol of whatever substance is comprised of ~6.022 10e23 molecules. Therefore if you were to degrade the genome to single nucleotides, you would get approx 10e-14 mol of these from any single diploid cells, that is 10 femtomol. In a million cells, you would have in the order of 100nmol.

The question might seem inane, but it HAS practical value. If you do have to actually totally digest genomic DNA like I had at some point, and you're given a definition of enzyme activity in unit based on nanomol of DNA, you just sit there and calculate

Now for molarity. While molarity wouldn't mean much, also because DNA is not really in solution in a nucleus, it is practically useful to know how much (mass of) DNA there is in a single cell.

The molecular mass of an average deoxyribonucleotide is 330 dalton. So one mol of it would weight 330g. Therefore 100nmol in your million cells above would weight 33ug. Which doesn't sound too far off, since DNA extraction yield for a million cells is actually around 8-10ug.

Happy?

Answer 2

The molar concentration of human DNA is approximately 6.022 x 10^23 molecules per mole, which is the same as Avogadro's number. This value represents the number of DNA base pairs in one mole of human DNA.

Answer 3

Each diploid human cell contains ~6pg genomic DNA.

Answer 4

2.1