Yup. DNA isn't the only vital organic chemical that builds itself in spirals. Proteins and sugars (all of them, I think, though I may be wrong about that part) also do so, IIRC both in a left-handed direction. In terms of energy release and general chemical behavior, the direction of the twist is completely irrelevant - but enzymes are shape keyed, and twist does matter to them. The body just wouldn't have the tools it'd need to usefully break down a dextro-rotating carbohydrate, say.
I don't think that the different structure would be toxic, and symmetrical molecules like, oh, say, alcohol would still work, but there'd be no nutrition to be had.
I can recall the topic coming up in a series of books by someone named Swann and in a short story by Spider Robinson.
So, short version: there's a one in four chance that a given alien biome would have happened to have both types of molecule break the same way Earth's did.
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"Reseeestunce ees fiutil. Yoo weeel bee Useemooletud. Borg Borg Borg."
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"V, did you do something foolish?"
"Yes, and it was glorious."
I don't think that the different structure would be toxic, and symmetrical molecules like, oh, say, alcohol would still work, but there'd be no nutrition to be had.
I can recall the topic coming up in a series of books by someone named Swann and in a short story by Spider Robinson.
So, short version: there's a one in four chance that a given alien biome would have happened to have both types of molecule break the same way Earth's did.
===============================================
"Reseeestunce ees fiutil. Yoo weeel bee Useemooletud. Borg Borg Borg."
===========
===============================================
"V, did you do something foolish?"
"Yes, and it was glorious."