Molecules that are not part of life?

[icakeov]

Are there any complex molecules that are not biomolecules and don't get "involved" with organisms and life building?

 

[Ygggdrasil]

Chemists are able to synthesize many complex molecules that are not biomolecules (e.g. carbon nanotubes, buckyballs, plastics). Sometimes these complex molecules can have effects on biological systems, even though they do not occur naturally (as is the case with many drugs).

 

[icakeov]

Thanks! What about naturally occurring molecules? Did they basically always find their way to integrate into life?
Or could there be some molecule out there that "stays away from life" or if it finds itself inside of living organisms, it doesn't really do anything?

 

[Hornbein]

Thanks! What about naturally occurring molecules? Did they basically always find their way to integrate into life?
Or could there be some molecule out there that "stays away from life" or if it finds itself inside of living organisms, it doesn't really do anything?

Buckyballs are naturally occurring. I believe that other graphite forms are too, though I don't keep track of this.

 

[icakeov]

I see. Basically, sounds like most molecules, especially complex ones are involved with life.

 

[Ygggdrasil]

Almost all naturally occurring complex molecules come from life (though this may differ in how you define a complex molecule). Cabon nanotubes and fullerenes can form in soot from fire, and these don't really do anything inside living organisms.

 

[icakeov]

I didn't have in mind molecules that are some crystal form of the same element necessarily. I specifically was thinking of complex molecules with many different elements in them.

 

[jim mcnamara]

two points:
One:
The terrestrial biosphere goes far down into rock and surface soils. Extremophiles exist in places you might not believe - boiling mud and the outer crust of many rocks and minerals, for example. So directly or indirectly biological activity is virtually everywhere. There are bacteria in ocean water that break down petroleum from natural seeps and now ocean going vessels; bacteria that stain rocks with manganese salts (desert varnish) and so on.

Two:
As of today there are a lot of polymers that do not degrade in landfills - polymers humans made. But - as bacteria evolve take advantage of all these newly introduced polymers they eventually will degrade as part of a newly minted metabolic pathway as well. We have seen it happen with the plastic used for laundry bleach bottles. So, in that sense, there are complex molecules created by life that are biologically inert. For a while.

As an aside, I was in a class long ago where the nature of required elements for life was discussed. The "fact" that silicon oxides and derived molecules were biologically inert was discussed. So, silicon was not ever used by plants. Few years later I learned that scouring rushes (horsetails - Equisteum and friends) have silicon oxide based lithocysts which work very like a plants version of sandpaper, and are great for cleaning dishes. I tried it. Cool.

So duh. That means the horsetail was able to uptake and transport silicon-based molecules from the soil into plant tissues. To do that requires chemically "messing" with silicon oxides. Meaning: ignorance is not proof of a concept. Or maybe: watch out for scientists who do not know that they do not know.

So beware of any answers that dogmatically state X molecule cannot ever, ever interact with any biological entity. Some exist now - true. But give it 100 years.
Edit:
@Ygggdrasil has a better shorter answer.

 

[jim mcnamara]

Hmm. May I ask if you've had a chemistry class. Organic molecules (carbon) and silicones pretty much rule the complex molecule domain. Maybe Buckyballs are what you are looking for...
Se Buckminsterfullerene: https://en.wikipedia.org/wiki/Buckminsterfullerene

 

[icakeov]

I am aware that carbon is everywhere and CHNOPS basically constitute life. I was just not sure if there was some "subgroup" of "complex molecules" somewhere on Earth that naturally form in nature, independent of life.

Thanks for responses everyone, super enlightening!

 

[icakeov]

I have a follow up question if anyone has thoughts on this one:
What would be the most complex molecule that is part of life and can arise naturally, without life being involved.
H₂0 clearly would be an example of a simple one. How much more complex than this molecular construct does it get?

 

[Baluncore]

Apatite is an important structural part of bones. It is also an important mineral.
https://en.wikipedia.org/wiki/Apatite
https://en.wikipedia.org/wiki/Hydroxylapatite
https://en.wikipedia.org/wiki/Bone_mineral
http://www.geol.lsu.edu/henry/Geology7900/Apatite/Apatite.htm

 

[icakeov]

Great! Thank you Baluncore!

 

[icakeov]

What about amino acids? Would they ever form spontaneously?

 

[Baluncore]

Some amino acids may be formed in hot springs or geothermal vents, but it will be hard to tell if they are the product of an inorganic chemical reaction or synthesised by live DNA.
https://en.wikipedia.org/wiki/Strecker_amino_acid_synthesis

 

[1oldman2]

How close to the subject is this?
http://www.kiss.caltech.edu/study/life/presentations/Hud.pdf

 

[jim mcnamara]

Also consider -
From wikipedia:

The Miller Urey Experiment. In the 1950's, biochemists Stanley Miller and Harold
Urey, conducted an experiment which demonstrated that several organic compounds
could be formed spontaneously by simulating the conditions of Earth's early
atmosphere.

After Miller's death in 2007, scientists examining sealed vials preserved from
the original experiments were able to show that there were actually well over 20
different amino acids produced in Miller's original experiments. That is
considerably more than what Miller originally reported, and more than the 20
that naturally occur in life [see chart on this page]

https://en.wikipedia.org/wiki/Miller–Urey_experiment

 

[icakeov]

Thank you so much Baluncore, 1oldman2 and jim mcnamara! Such great resources and they really address the topic and answer the question.
I realize I'd seen this one video before which I think quite nicely describes some of processes your references talk about.

Again, much appreciated!

 

[Kevin McHugh]

Almost all naturally occurring complex molecules come from life (though this may differ in how you define a complex molecule). Cabon nanotubes and fullerenes can form in soot from fire, and these don't really do anything inside living organisms.

Carbon can be organic such as in alkanes or inorganic, as in CO, CO₂ CO₃^-2, and HCO3^-. Graphite, soot, buckyballs, fullerenes and diamond are all also inorganic. While inorganic carbon interacts with living systems, they are not necessarily "life" molecules. Even organic carbon compounds do not participate in life chemistry. For example, polyethylene glycol, oligomeric and polymeric alkanes.

 

[Kevin McHugh]

I am aware that carbon is everywhere and CHNOPS basically constitute life. I was just not sure if there was some "subgroup" of "complex molecules" somewhere on Earth that naturally form in nature, independent of life.

Thanks for responses everyone, super enlightening!

Kerogen is an example of a geopolymer that is derived from organic detritus under high temps and pressures. During breakdown of the source rock, complex organic molecules are formed such as higher branched and linear alkanes, polycondensed aromatic hydrocarbons, and porphyrins. Porphyrins are derived from chlorophyll in the sediments, and are present in crude oil as erythroetioporphyrins. While derived from life molecules, these porphyrins do not participate in life chemistry.