The A in DNA

[vertex87]

Why is DNA an acid? (as its name suggests..) What gives the DNA the acidic property?

[Poison]

Yes, DNA is an acid. In the structure of DNA, there is sugar (deoxyribose), a phosphate ion, and a nitrogenous base.
the phosphate ion gives the acidic property.

[biostudent84]

Which is kind of funny because the nitrogen base really IS a base. One acid made up of a long chain of bases.

[Freedom]

Isn't DNA amazing.

[2810712]

Ok. DNA consists of both acidic subunits and basic subunits ; also their no. is nearly equal; then why is DNA acidic. I think, the strength of acid [po3]is more than base [N-bases]. but, how will U compare the strength of an acid with that of a base ?
hsg

[dandan]

Ok. DNA consists of both acidic subunits and basic subunits ; also their no. is nearly equal; then why is DNA acidic. I think, the strength of acid [po3]is more than base [N-bases]. but, how will U compare the strength of an acid with that of a base ?
hsg

well, you can compare the strength of the acid by comparing it to the base strength through Kb and Ka values, where Ka = Kw/Kb.

also, since the phosphate backbone is on the outside, and the bases are hidden safely inside due to the structure of the DNA, only the acidic portion is free to react with the outside environment... thus making it more important.

[dr.pnj]

what a coincidence
my teacher asked us the same q in our class quiz today
the ans is
the phosphoric acid present in the DNA gives it its acidic nature
h3po4 itself becomes po3(-3)
one oxy is negatively charged and another one contains a lone pair of e-
the other two are bonded
one to upper 3rd c of deoxyribose sugar and second to 5 c of lower sugar
so two oxy atoms are freefor rxn
while in dna the bases are paire d by hydrogen bonds which may be broken but req energy fot that so the acidic nature
hope you get that