# Largest organic compouds

Discussion in 'Chemistry' started by Chatha, Mar 2, 2007.

1. ### Hercules RockefellerBeatings will continue until morale improves.Moderator

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Only one person has answered correctly. DNA is by far the largest organic polymer in existence. Nothing else comes close. Let’s take human chromosome 1 (the largest human chromosome but not the largest chromosome in nature) as an example:

A chromosome is comprised of one continuous double stranded molecule of DNA. The two stands are held together by hydrogen bonding, so each single strand is its own distinct molecule.

Chromosome 1 has 247,249,719 bases (each strand).

• Purines (adenine and guanine) have 5 carbon atoms.

• Pyrimidines (cytosine and thymine) have 4 carbon atoms.

• Ribose has 5 carbon atoms.

• Phosphate has no carbons (PO[sub]4[/sub][sup]-[/sup])

So, let’s use the average of the number of carbons found in purines and pyrimidines for each position in the DNA strand:
4.5 carbon atoms.

Each position on the strand is comprised of a base (either purine or pyrimidine), a ribose and a phosphate. These three items together are called a “nucleotide”.

Total carbons for each nucleotide (base + ribose + phosphate) is:
4.5 + 5 + 0 = 9.5 carbons.

Multiply this by the number of nucleotides in chromosome 1........

9.5 x 247,249,719 = 2,348,872,330 carbons!!!!

My quick calculation of the complete formula for the DNA molecule in chr1 is:

C[sub]2348872330[/sub]H[sub]2719746909[/sub]N[sub]741749157[/sub]O[sub]1483498314[/sub]P[sub]247249719[/sub]

This may be a little off as I have taken averages for the composition of the four nitrogenous bases, but it will be pretty close.

3. ### PositronAgony: Not all pain is gainRegistered Senior Member

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Well I would agree DNA is the largest organic molecule but that's something most people know already. I'm still curious as to the Second largest though.

5. ### FacialValued Senior Member

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DNA is a coded polymer, meaning that it would have monotonous digital properties.

Just about every other polymer, outside RNA, would carry no information and have a single monotonous analog property.

A protein is very large, and in general they have non-monotonous, or unique, analog properties.

It really depends on what functional properties you want to look at.
If it's all-out biggest, then I would probably say a protein polymer, such as spider silk (I don't know the actual one).

7. ### ChuchRegistered Member

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Buckyballs are kinda large but they have a long way to go for being the largest. However they are most certainly smooth and very nice to look at.

Honestly I find fullerenes very impressive. You can hear about new idea or invention concerning these almost every day.

8. ### exchemistValued Senior Member

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I'd nominate graphite I think. Any giant structure can be made large enough to exceed the molecular weight of the largest molecule. And graphite is simply the extreme case of the fused ring category of organic compounds.

But in a way it's a slightly silly exercise.

9. ### DaveC426913Valued Senior Member

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Is graphite a molecule? I thought it would be a crystal. Aren't they bound differently?

10. ### exchemistValued Senior Member

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Yes, it's a giant structure. But the OP asked about organic compounds, not molecules specifically. (And molecules form crystals, too.)

I have my tongue a tiny bit in my cheek, but when you consider fused ring systems, for example pyrene: https://en.wikipedia.org/wiki/Pyrene
or the asphlatene family (familiar to me from my time in the hydrocarbon industry): http://pubs.rsc.org/services/images...e/2015/OB/c5ob00836k/c5ob00836k-f1_hi-res.gif, you can easily see that by fusing more and more 6-members aromatic rings you eventually end up with a graphite sheet.

One can argue the toss as to whether graphite should be classed as "organic" or "inorganic", but it is in effect the limit case of a fused aromatic ring structure, with sheets stacked on tope of one another and bound by Van der Waals forces.

11. ### DaveC426913Valued Senior Member

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I understood that carbon alone is not considered a sufficient qualifier to be organic.

Seems by some accounts, organic is synonymous with hydrocarbons,i.e.: carbon backbone with hydrogens.

12. ### Write4UValued Senior Member

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From wiki
Hazen calls these the cause for the rare species which emerge in specific environments, the rare species which combined have a larger bio-mass than the entire population of the earth.
https://en.wikipedia.org/wiki/Biomolecule

Well, we know that we have at least one chromosomes which is twice as long as was originally designed.
And an actual visual of the modified chromosomes is demonstrated here:
http://www.evolutionpages.com/chromosome_2.htm

One less chromosome than apes, but twice its normal size....

Last edited: May 1, 2018
13. ### Write4UValued Senior Member

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Was looking for a home for this little tidbit. This may be of general interest. A new carbon!

https://www.sciencenews.org/article..._medium=email&utm_campaign=editorspicks081819

14. ### exchemistValued Senior Member

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Thanks for this. I don't quite understand how the apparent 9 sided ring is made up, given the structure they describe: https://en.wikipedia.org/wiki/Cyclo(18)carbon

By rights it ought to be aromatic, as it has 4n+2 electrons in a ring of conjugated π-bonds. If so then it is not really correct to draw it as simple alternating single and triple bonds. But I don't see any reference to aromaticity in the articles about it. Curious. I've asked one of my old tutors, who worked on aromatic ring structures, about it.

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15. ### Write4UValued Senior Member

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I did notice this qualifier
https://science.sciencemag.org/content/early/2019/08/14/science.aay1914

Would that suggest the behavior of aromatics?

16. ### RainbowSingularityValued Senior Member

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17. ### exchemistValued Senior Member

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No.

It probably refers to the steric strain inherent in bending the bonding out of its preferred configuration. A system of alternating single and triple bonds would naturally be linear. So bending it into a ring involves a suboptimal overlap of the p orbitals in the π bonds that are in the plane of the ring. The Wiki link I provided includes an estimate for this "strain energy", i.e. the amount by which the molecule is less stable than the bonds would be, if allowed to take up their preferred linear configuration.

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18. ### Frank SchmidRegistered Member

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PG5 is 10 nanometers in diameter, Molecule has about 15 million carbon and 40 milliom hydrogen. Its molecular weight is 200 million g/mol (approx). This is far bigger than the previous record-holder, polystyrene polymers that were only 40 million hydrogen atoms.

19. ### RainbowSingularityValued Senior Member

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compound = a mix of things
organic = living ? or = biological components i.e hydrogen/water/etc...

the ocean occurred to me as a question of if the ocean is by its nature an organic compound
is there a delineation point between dead water and living water by the O2 content etc .. ?
is this transferable to suggest the ocean its self has a state of "living" or "livability" that potentiates the nature of its body encompassing a state of entity by its capacity to function life in it(compound)... ?

the magic soup

https://en.wikipedia.org/wiki/Primordial_soup