History Main / MirrorChemistry

** The chirality issue is vastly overstated by the game. If what ''MassEffect'' says is true, then we all should've long been dead, as there are enough "wrong" stuff (such as D-amino acids or L-sugars) around that by this logic every human runs a risk of a severe allergic reaction or even death... Though severe and potentially fatal allergic reactions in such circumstances, while pretty rare, are not unheard of, so the fear is not ''completely'' unfounded.
*** It may depend on what exactly is ingested. A bartender in Mass Effect 2 warns you not to eat from a bowl of snacks intended for Turians and Quarians, but the only consequence she gives for doing so is "cramps" (perfectly logical if we assume the matter would simply pass through your system undigested).

Most of the molecules required for life have the property known as [[http://en.wikipedia.org/wiki/Chirality_(chemistry) chirality]] or "handedness". That is, they are not the same as their mirror image, like a left shoe which will not fit properly on your right foot no matter how you rotate it. That wouldn't have been that much of a problem, if not for the one insignificant fact that most of the stuff our bodies are made of, mainly the amino acids, which are the building blocks for the proteins we consist of, are chiral. And ''all'' multicell organisms on Earth are made of L-(or levo-)amino acids: that is, most of the molecule's atoms are on the left side.[[hottip:*:This is not to be confused with the molecule's optical activity: that is, if we shine a light through its solution, l-isomer will rotate its polarization plane (a plane the EM-wave is oscillating) to the left, that is, counter-clockwise, and d-isomer, or dextrorotatory one, will do it to the right, or clockwise. Many L-isomers are in fact l- (or (-), as chemists now prefer to designate them) isomers, and vice versa, but it's not true for all of them.]] Dextro-amino acids (except cysteine) are exceedingly rare in Earth organisms and are used only by some bacteria and in a few very specialized cases by larger creatures. Referencing this fact is a fairly common way for science-fiction writers to ShowTheirWork. It generally comes up in one of two situations:

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** The chirality issue is vastly overstated by the game. If what ''MassEffect'' says is true, then we all should've long been dead, as there are enough "wrong" (such as D-amino acids or L-sugars) that every human runs a risk of a severe allergic reaction or even death... Though severe and potentially fatal allergic reactions in such circumstances are not unheard of so the fear is not completely unfounded.

* In ''ThereAndBackAgain'' by Pat Murphy, anyone who passes through a wormhole gets mirror-reversed. Any gathering of people who have done a lot of wormhole travel needs two cooks: one for the travelers who are currently "right-handed" (having passed through an even number of wormholes) and one for the ones who are "left-handed" (having passed through an odd number).

** The chirality issue is vastly overstated by the game. If what ''MassEffect'' says is true, then every human who's ever had tea with mint and sugar, and every human who's ever taken oral penicillin, runs a risk of a severe allergic reaction or even death... because mint and sugar get their flavor from D-amino proteins, and penicillin is one of only a few bacteria that actually have D-amino acids instead of L-amino like most other life forms on earth. Though fatal/potentially fatal allergic reactions are not unheard of so the fear is not completely unfounded.

** The chirality issue is vastly overstated by the game. If what ''MassEffect'' says is true, then every human who's ever had tea with mint and sugar, and every human who's ever taken oral penicillin, runs a risk of a severe allergic reaction or even death... because mint and sugar get their flavor from D-amino proteins, and penicillin is one of only a few bacteria that actually have D-amino acids instead of L-amino like most other life forms on earth.

In either case, this usually manifests itself as an inability to eat the same food in the same way. Either food tastes different depending on your handedness, or wrong-handed food has no nutritional value or is actively dangerous. Expect some mention of the fact that ethanol is one of the few biologically interesting molecules that doesn't have this property -- so, regardless of chirality, everyone can always get drunk together, and you can make moonshine from organic stuff that's otherwise useless for you because it's of the wrong chirality.

* ''Literature/DoorwaysInTheSand'' by Creator/RogerZelazny has an "''n''-axial inversion device", which mirror-reverses anyone or anything that passes through it. The protagonist goes through it about halfway through the book. It turns out that quite a few things taste better when you're mirror-reversed. Especially [[ImpossiblyDeliciousFood bourbon]].

* ''{{Doorways in the Sand}}'' by RogerZelazny has an "''n''-axial inversion device", which mirror-reverses anyone or anything that passes through it. The protagonist goes through it about halfway through the book. It turns out that quite a few things taste better when you're mirror-reversed. Especially [[ImpossiblyDeliciousFood bourbon]].

** Also played GenreSavvy by big pharmaceutical companies. A company will frequently develop and market a medication consisting of some compound in a racemic mixture, sell that until its patent exclusivity expires, and then release a "new" medication consisting of only the biologically active enantiomer of the original compound, so as to gain a whole new patent life for essentially the same compound. A good general clue to this tactic is a generic drug name that looks like the original with a S or D added. Examples include Prilosec (omeprazole) vs. Nexium (esomeprazole), Celexa (citalopram) vs. Lexapro (escitalopram), Claritin (loratadine) vs. Clarinex (desloratadine), and so on.

** Also played GenreSavvy by big pharmaceutical companies. A company will frequently develop and market a medication consisting of some compound in a racemic mixture, sell that until its patent exclusivity expires, and then release a "new" medication consisting of only the biologically active enantiomer of the original comopund, so as to gain a whole new patent life for essentially the same compound. A good general clue to this tactic is a generic drug name that looks like the original with a S or D added. Examples include Prilosec (omeprazole) vs. Nexium (esomeprazole), Celexa (citalopram) vs. Lexapro (escitalopram), Claritin (loratadine) vs. Clarinex (desloratadine), and so on.

* ''Spock Must Die!'' by James Blish, the first ''StarTrek'' ExpandedUniverse novel, has a mirror-reversed copy of Spock created in a transporter accident. He's unable to eat anything, and so he finds himself slowly starving while he works with a chemistry set in order to create mirrored food he can eat and survive.

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!!Examples:

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* One of the stories in ''Literature/CallahansCrosstimeSaloon'' has a "Mirror Earth" with right-handed proteins in the place of our left-handed ones. The protagonists eventually discover that this inverts the perceived quality of liquor: our swill is their Wonderbooze and vice versa.

* The IsaacAsimov short story "Left to Right" has a scientist create a device that will apply some sort of directional interchange on whatever passes through; the scientist intends to use himself as a test subject. There is a discussion about potential issues if he ends up with his heart on the wrong side or unable to eat because of wrong-handed proteins, but he plans on reversing himself again before that becomes an issue. It turns out not to matter; the device actually just [[spoiler:[[{{Feghoot}} changes the scientist's name from Robert L. Forward to Robert L. Backward.]]]]
* An important plot point in David J. Lake's ''The Right Hand of Dextra'' and ''The Wildlings of Westron''. Dextran food tastes vile and has no food value for humans; the same applies to Dextran natives and terrestrial produce. [[spoiler:Of course, the Dextran [[StarfishAliens Mothers]] can alter a creature's biochemistry. (Which has the side-effect of creating a connection to the [[GeniusLoci planetary over-consciousness]].)]]

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* In ''{{GURPS}} Time Travel'', this is one of the entries on the "something went wrong with our dimension-traveling device" chart.

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* The artificial sweetener Aspartame (which you might see under trade names NutraSweet (tm) or Equal (tm).) One enantiomer tastes sweet (sweeter than sugar, in fact), and the other tastes bitter. (This is why diet sodas can taste "off" to some people.) Also worth noting that citric acid reverses the bitter enantiomer into the sweet one.

* From the files of the WebOriginal/SCPFoundation comes [[http://www.scp-wiki.net/scp-739 SCP-739]], a small closet with mirrored interiors. Closing a person in the booth once will flip all their amino-chains. Closing them in twice will switch them back, but repeating the experiment too many times with the same subject leads to [[CameBackWrong something else emerging]]. As a [[MundaneUtility fun side benefit]], locking sugar packets in the closet will flip them as well. The scientist specifically notes that they would make excellent diet sweeteners.

Most of the molecules required for life have the property known as [[http://en.wikipedia.org/wiki/Chirality_(chemistry) chirality]] or "handedness". That is, they are not the same as their mirror image, like a left shoe which will not fit properly on your right foot no matter how you rotate it. Referencing this fact is a fairly common way for science-fiction writers to ShowTheirWork. It generally comes up in one of two situations:

* From the files of the SCPFoundation comes [[http://www.scp-wiki.net/scp-739 SCP-739]], a small closet with mirrored interiors. Closing a person in the booth once will flip all their amino-chains. Closing them in twice will switch them back, but repeating the experiment too many times with the same subject leads to [[CameBackWrong something else emerging]]. As a [[MundaneUtility fun side benefit]], locking sugar packets in the closet will flip them as well. The scientist specifically notes that they would make excellent diet sweeteners.

* In ''ThroughTheLookingGlass'', Alice speculates that looking-glass milk might not be good to drink. This is probably the UrExample; in fact, it predates the coining of the word "chirality" by several years. In ''The Annotated Alice'', MartinGardner discusses the chemical reasons why this would be true, before moving on to point out that looking-glass milk would likely be made of antimatter, making it ''[[StuffBlowingUp really]]'' bad to drink.

* Receptors for proteins, hormones, and other organic chemical compounds are made to fit certain molecular structures of a certain chirality. If a molecule does not have the correct chirality, it doesn't fit in the receptor, or worse, can actively harm the organism. This was what happened with Thalidomide - a certain chiral structure (also called an enantiomer) of the compound was useful for the effects of morning sickness in pregnant women, but the other enantiomer of it caused terrible birth defects. This is also the case with the cancer-fighting drug Platinol, which only causes sickness because scientists can't separate the helpful enantiomer of the drug from the toxic one, so it's sold as a mixture of the two (any mixture of both enantiomers of a compound is called a racemic mixture).

** Splenda is non-nutritive modified sugar, though the modification doesn't involve chirality. The foregoing discussion points out the fallacy both of Splenda's tagline "Made from sugar, so it tastes like sugar" and the assumption that reversing chirality would leave the flavor intact (might, but doesn't have to) -- among the chemical properties that could be affected are, indeed, those that our bodies use to detect flavor.

* One of the stories in ''CallahansCrosstimeSaloon'' has a "Mirror Earth" with right-handed proteins in the place of our left-handed ones. The protagonists eventually discover that this inverts the perceived quality of liquor: our swill is their Wonderbooze and vice versa.

* From the files of the SCPFoundation comes [[http://www.scp-wiki.net/scp-739 SCP-739]], a small closet with mirrored interiors. Closing a person in the booth once will flip all their amino-chains. Closing them in twice will switch them back, but repeating the experiment too many times with the same subject leads to [[CameBackWrong something else emerging]].
** As a [[MundaneUtility fun side benefit]], locking sugar packets in the closet will flip them as well. The scientist specifically notes that they would make excellent diet sweeteners.