/sci/ - Science & Math

This line of thought also got me thinking. Viruses aren't technically alive and we aren't certain whether or not they share a common proto-life ancestor with the life on Earth or if they formed out of the primordial ooze independently.

If chirality of life was truly random, then there is a 50% chance virus DNA has the opposite chirality. However I have yet to find anything on topic of virus DNA chirality.

>>6447317
>Viruses aren't technically alive
Technically that depends on the definition you pick.

>The chirality of life is generally believed to have been a matter of chance
get a load of these faggots

>>6447321
Commonly accepted that they're not alive but run off mechanisms of other organisms.

Does the ability of enzymes to break down the amino acids and sugars in our food rely on the chirality or could them down either way?

The chirality of amino acids is fundamental to life on Earth and the fact that all life on Earth shares the same chirality of sugars means that a given chirality of amino acids directly translates into a specific sugar chirality, L amino acids lead to D sugars and D amino acids would lead to L sugars, but is that true of every other molecule in the body, like fats and proteins?

>>6447317
but viruses need to hijack other organisms to reproduce.

those with the wrong chirality wouldn't be able to and thus would disappear.

Or wouldn't appear at all.

>>6447296
Did you read pic related? In it, astronauts reach a planet where all the organisms have chirality opposite to ours. Fun things happen: for one, the astronauts and the natives are totally immune to one-another's pathogens, but (for some stupid reason) can't digest or gain nourishment from one-another's food (which passes harmless through them.

One of the adorable, furry little natives innocently and unthinkingly gobbles a delicious-looking earth-strawberry, and the astronauts are like "oh, fuck!" Hilarity ensues when the little bugger eventually poops out completely unharmed strawberry seeds, which take root and grow in the fertile soil. Nothing in the environment can harm the strawberry plants, and the grow rampantly, a truly invasive plant. It is feared that the strawberry vines will eventually out-compete all other plant life on the planet. The astronauts program self-aware self-replicating spider robots to scour the surface, eradicating the strawberries and their vines with lasers iirc.

It's an amusing book which explores such things as zero-g sex and crib-death.

>>6447342
Good point. I probably should have thought of that given I asked whether or not viruses of opposing chirality could infect us.

>>6447365
I did some searching on the subject of biological chirality yesterday and I came across a wikipedia page of chirality in popular fiction. I read a the background synopsis of a few science fiction novels on the page, but it seems like that particular novel isn't mentioned. We should probably add it.

> http://en.wikipedia.org/wiki/Chemical_chirality_in_popular_fiction

>>6447323
Most dismiss the topic of the chirality of life as a matter of chance, but some theorize that either one chirality may have an advantage over the other or that the polarization of light may have played a roll in the handedness of amino acids on early Earth. One theory is that the polarization of light scattering within Earth's oceans and then reflecting back off the water's surface may have been the cause. Another theory is that amino acids came from space and that the polarization of light due to the particles of the interstellar medium aligning themselves with the galactic magnetic field led to amino acids of a given chirality being more common than the other.

Interesting stuff.

>>6447365
Larry Niven's novel Destiny's Road about a human generation ship arriving at a world to colonize only to discover that the food is inedible because it has an opposing chirality. They end up using the atmospheric transport ship's engines to sterilize an entire peninsula to grow their own food. Later, native seafood becomes a popular diet food among the descendants of the colonists because they don't get any calories from it.
>the twist is that the planet's biosphere finds potassium poisonous and native marine species over the last billion years used it as a poisonous defense mechanism and have thus concentrated most of the planet's potassium at the deepest reaches of the ocean in their dead bodies. The majority of colonists end up with serious brain damage due to the lack of potassium before a usable source of potassium is discovered.

In the Mass Effect series, "levo" and "dextro" species live side by side by neither can eat the others food because it causes horrible stomach cramps, allergic reactions, and sometimes death.

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