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by dotBen 5685 days ago
During 'regular' photosynthesis water (H2O) is broken down during Oxygen Evolving Complex to leave the individual atoms (H and O) along with protons and electrons which fuel photosynthesis.

The idea behind the arsenic theory is that arenate, which has 4 O atoms, could provide act as a suitable substrate during Oxygen Evolving Complex to provide the same protons and electron break down.

There is also a parallel chain of thought that arsenic is similar in its makeup to phosphorus, which is needed to create DNA and other genetic material, and so it could help cell division. However, I'm doubtful as arsenic is toxic in any real quantity and thus would be counterproductive to that.
2 comments
electromagnetic 5685 days ago
Arsenic is only toxic to our understanding of biology. Some extremophiles have unbelievable resistance to heavy metals, so I wouldn't doubt some configuration of our biology would be resistant to arsenic.

However, with the problems arsenic causes blocking PDH enzyme, causing H2O2 in the cells and a huge list else like IIRC thiamine deficiency.

Then again, life exists in such a broad range of conditions that I find it hard to believe that life couldn't adapt to life with arsenic for one main reason. If it is using arsenic as a DNA base, it means it is sequestering the arsenic rather than leaving it in the cells to do damage.

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electricsheep 5682 days ago
In retrospect, this is priceless...
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dotBen 5685 days ago
BTW, the New Scientist paper mentioned [1] in the kottke.com post, refers to Mono Lake [2] here in California as a location they are studying some of this. It's basically on the far side of Yosemete if you are driving from the Bay Area.

If you are at all a bio geek, you really must check it out - it's a low-oxygen, alkali-rich simple ecosystem that supports a clearly visible food chain of about just 5-6 spices. The place is weird, creepy and totally amazing.

What was supposed to be a romantic road trip planned by my girlfriend for my birthday became an unexpected biology field trip.

[1] http://www.newscientist.com/article/dn14537-arseniceating-ba..., [2] http://en.wikipedia.org/wiki/Mono_Lake

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cloudwalking 5684 days ago
This is cool, thanks for sharing.
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