DNA stands for DeoxyriboNucleic Acid. To what extent does it behave like a garden-variety acid? Could you fill a beaker with aqueous DNA in the same way that you can fill a beaker with aqueous hydrochloric acid, citric acid, or ascorbic acid? Does DNA taste sour, turn litmus paper red, and react with bases like bleach or ammonia?
I can’t speak much about the biology of it all, but acids (and bases) are all about hydrogen ions and the bonds they form due to their charges (positive/negative). The nucleotides (made of phosphates which are acidic) make up our DNA are non-covalent hydrogen bonds, forming base pairs (each side of the double helix ladder), and can come apart pretty easily. The molecules themselves are very long polymers, so I’m not quite sure what you’d get if you had a glass full of only DNA. The amino acids are crucial for forming proteins and lipids (hydrophobic fatty acids).
I wouldn’t want to taste it, but most acids do taste sour.
I can’t answer the question even remotely fully, but in “The Genetic Code” by Isaac Asimov he talks about how in the early decades of the study of DNA, when biochemists had just recently become aware it even existed and still assumed some type of massively complex super-protein stored the actual data of life, all of the DNA that was being successfully extracted from cell nuclei was very badly fragmented by the process, resulting in the true complexity of the molecule being hidden- it was assumed to be just some chemical of minor note that happened to be found in cell nuclei. This may have had an impact on how they interpreted DNA’s chemical properties and chose to name it.
No, the name is given by its chemistry. There is a “priority order” to how organic molecules are named, and any which contains certain groups will be called acid. The fact that DNA is actually a family of polymers (the exact composition of each strand of DNA in a single cell is different from every other strand) and that the first extractions were fragmentary doesn’t change its nature: biochemists figured out pretty early that it was a variable polymer and that it contained “acid” groups: DNA is DNA no matter how long the strand.
Wait, this just struck me- if DNA is an acid, why are some of the major molecules that combine to form it called nitrogenous bases?
Is this a completely different usage of the word ‘base’?
The bases are part of the DNA, and they are bases in the “acid/base” sense; when taken separatedly, apart from the rest of DNA, they are basic in nature. They’re cyclic amines. The smalles units of DNA are the nucleotides, each of which is composed of 1 phospate + 1 deoxiribose + 1 base.
Yes, you can have an aqueous solution of DNA, although, due to the great length of most DNA molecules, even quite a dilute solution would be very gooey. It is, I believe, quite a weak acid, and there are lots of complicating factors, so I am not sure about the taste, but I suspect it would turn litmus paper red, and it would certainly react with bases.
It is worth noting, however, that a pure solution of DNA is quite difficult to make. In the cell the DNA is tightly bound to various proteins, most of which are basic, and it is quite difficult to disassociate it from them without damaging the DNA itself (although I dare say teh techniques to do so are quite routine by now).
Maybe so, but I think you will find that (due to the phosphate groups in its backbone) DNA does in fact behave as a weak acid. Watson was able to quickly recognize that Pauling’s proposed structure for the DNA molecule was incorrect, because, on Pauling’s model, DNA would not have been acidic.
I am not sure how this is relevant to the OP’s question.
I am not sure what you mean by “pretty early”, but its polymeric and variable nature was not generally accepted by biochemists before Watson and Crick’s famous work (1953). Before that, the most widely accepted model was that the DNA molecule was a tetramer of 4 nucleotides, containing one each of the four DNA bases. (Very few people believed it to be the genetic material at this time. Although there was evidence pointing in that direction, most scientists discounted it, because they thought the DNA molecule was too small and simple to play such a role.)
No, it is the same usage, but the bases in DNA are on the inside of the molecule, bound to one another, and so not normally available for reacting with other substances. The acidic parts, the phosphates, however, are on the outside of the molecule and thus are available to react with other things. Thus the molecule behaves as an acid.
Not really.
G, A, T and C are bases in that they are looking for hydrogen protons (or are looking to donate an electron), IIRC.
The DNA molecule is composed of acids and bases. And now that I think about it, these particular molecules mot not be attracted by charge necessarily, but by their ability to donate or acquire an electron from a hydrogen ion.
Now it’s getting a bit above my head… * sneaks out the back*
DNA consists of a backbone in which desoxyribose units (a kind of sugar) are liked by phosphate (or phosphoric acid) groups. Phosphoric acid can release three protons. In DNA, two of these are replaced by ester bonds to the sugar moieties, the third one is acidic, giving the “acid” name to DNA. However, it is a strong acid (pKa around 0), therefore under physiological conditions, the DNA backbone is deprotonated and negatively charged, DNA is present as a salt, with positive ions compensating the negative charge of the phosphate groups.
To each sugar unit, a base is covalently attached. These are weak bases, as the nitrogen atoms are part of an aromatic system. They are not charged under physiological conditions. Hydrogen bonds between complementary bases in the two strands of the DNA keep the two strands together
And people thought Prometheus had no merit. It all makes sense now…
Does it look like semen or vaginal moisture during arousal (whatever the hell that’s called)? That would be cool.
I am not really sure what you are thinking, but neither of those fluids (nor any other bodily fluid) contain DNA in solution. In semen, the DNA will all be neatly packaged up in the heads of the sperm cells, and there should not be any at all in vaginal fluid. (Well, except for what might be in any stray skin or blood cells that get into it; but, again, the DNA there will all be packaged up in the cell nuclei.) The gooeyness of those fluids is due to mucoproteins.
Actually, if you extract it from solution DNA looks a like translucent mucus- stringy slimy stuff.
Depends on how you extract it. If you spin it down in ethanol, you end up with a tight solid white pellet, for instance. And then you do a little happy dance because you know that your extraction worked.
Well, it depends on how pure you want. You can actually precipitate DNA in your kitchen. Some meat tenderizer will dissolve away the protein, dish soap gets rid of the lipids, and then concentrated ethyl alcohol will extract DNA. (Directions are easily available on line; I’m not guaranteeing I’ve got the steps in the right order).
I think the kitchen extraction is pretty close to the standard laboratory technique for bulk extraction (the step before spinning it down like Smeghead does).
Really? I am skeptical as to whether meat tenderizer is powerful enough to dissolve away the more tightly bound chromosomal proteins, such as the histones. (These, indeed, were actually principally what I had in mind when I talked about “pure” DNA. The histones are quite strongly basic, and neutralize the acidity of the DNA itself. If you want DNA to act like an acid, you have to purify it by removing them.) Meat tenderizer may be good at (partially) breaking down the actomyosin of muscle tissue, but that does not mean it will break down all proteins. Indeed, it consists of enzymes, which are proteins themselves. If it digested all proteins it would digest itself!
It doesn’t give tremendously good quality DNA, but the protocol is good enough for high school bio students to play with. It’s pretty widely used for bio labs these days.
We used to use proteinase K back five or six years ago when I was doing high-quality DNA extractions on a daily basis.
I always skip the spinning step, and move straight on to the pan frying.
Mmm…mucoproteins.
ETA: I like savory aspics of all kinds–pass me the gefilte fish jar with all the jelly, please.
Gelatins from cartilage and bone: are these mucoproteins?