Calculating moles from base pairs ??

[lulubell]

Calculating moles from base pairs ??

• Quote

Post by lulubell » Tue Apr 17, 2012 3:48 pm

Hi,
I'm trying to figure out the moles of a piece of DNA- using just the following information .....

The genomic DNA is 20000ng (mass) and is 15000 base pairs long

I know to get moles you have to do; Mass/ relative formula mass <--- but I don't know this....

Is it possible to do; mass/base pairs to get the number of moles?

In which case it would be 20000/15000 = 1.333 M ??

I then need to find the mass (in ng) in 1 mole- I know how to do this, but obviously if I get the first part wrong, my answer here will be wrong also

Any advice?

[JackBean]

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Post by JackBean » Tue Apr 17, 2012 8:22 pm

1500 bp is not molecular weight. For this you need average weight of nucleotide and with the number of nucleotides in molecule you calculate the molecular weight of the whole molecule. hat you use to calculate concentration.

But the concentration of DNA is usually in mass per volume (e.g. ng/ul).

[taruntbiotech]

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Post by taruntbiotech » Mon May 14, 2012 5:31 pm

see this hope it will help u

Single-stranded: 330 grams per mole per base
330 (g/mol)/b
330 g / ( mol • b )

Double-stranded: 660 grams per mole per base pair
660 (g/mol)/bp
660 g / ( mol • bp )


Example problem:

Find the number of moles which compose a 1.5kb band whose mass was determined to be 120 ng (by gel comparison to standards).

(120 n g ) • ( mol • bp ) = 1.2E-4 nmol or 0.12 pmol
(1500 bp) ( 660 g )

[taruntbiotech]

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Post by taruntbiotech » Mon May 14, 2012 5:35 pm

molbiol.edu.ru/eng/scripts/h01_07.html
also check this