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Home Q & A Board Biology-Related Homework Help General Biology
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gh1991 gh1991
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13 years ago
CALCulate the amount of DNA present iin your sample if the absorbance at 260 is 0.3
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13 years ago
You can measure it either using a UV spectrometer or by gel electrophoresis.

With a UV spectrometer:

First diluted you DNA (I usually use 5 uL in 995 uL). Then adjust the spectrometer at 260 nm with your blank. Measure your DNA sample. You can then use the following formula to estimate the DNA concentration:

concentration = 260 reading * Absorbance factor * dilution factor (i.e. 200)

Absorbance Factor
ssDNA: 37 µg/ml
dsDNA: 50 µg/ml
ssRNA: 40 µg/ml

You can also measure the purity sample by calculating the ratio of the A260/A280

Using gel electorphoresis:

Run your sample with a molecular marker that has stantard DNA concentration. You then take the picture. Depending on the imaging material you will have to use different things. If you have a imaging hardware and software, there is a program that allows you to measure the intensity of a marker band of a size identical to your DNA sample and you can compare it to the intensity of your DNA sample. You then use the concentration of the stantard to estimate the concentration of your sample.
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bio_manbio_man
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