DNA the genetic material

[rx8man88]

DNA the genetic material

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Post by rx8man88 » Mon Dec 11, 2006 12:22 am

Briefly describe the experiments which led to the knowledge that DNA is the genetic material.

A link, or just an outline, or something.

[honeev]

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Post by honeev » Mon Dec 11, 2006 3:17 am

get an idea from this... http://library.thinkquest.org/20830/Tex ... search.htm

[victor]

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Post by victor » Mon Dec 11, 2006 11:48 am

Umm....I wanna ask something. I've done the nucleic acid extraction from fruits and one of the final step is the precipitation of nucleic acid by cold ethanol. Does anyone know the mechanism of this work of ethanol? Please give me a link or a hint.....

What I could think is that ethanol may has an equal density as nucleic acid, so, it would precipitate the nucleic acid from other debris like protein which will get precipitated at the bottom of the reaction tube while nucleic acid is on the top of the solution. Is it true? or is there any other mechanism?

Please help,
Victor

[G-Do]

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Post by G-Do » Tue Dec 12, 2006 1:31 am

Hi Victor,

OT, but I always understood that we do this because DNA is insoluble in ethanol (DNA has a negatively charged phosphate backbone and ethanol is an organic solvent). So it has the effect of making the DNA come out of solution.

Cheers.

[victor]

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Post by victor » Tue Dec 12, 2006 4:24 am

Well, if ethanol is an organic solvent, then it must be a non-polar solvent and insoluble in water. But what we got from ethanol is that it's soluble in water, thuus it's not an organic solvent. is that right?

[zzp1029]

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Post by zzp1029 » Tue Dec 12, 2006 11:11 am

The ethanol , precipitating DNA , is not actually pure ethanol. It includes a little water that can solven planty of salt from DNA. it benefit of extrction of more pure DNA, I thought.