History Main / MirrorChemistry

* ''Literature/TourOfTheMerrimack'': The crew aren't worried about picking up any diseases in the Myriad because life on those worlds uses opposite-handed proteins, which are are incompatible with human biology. It's likened to attempting to attach a four-post wheel to a five-post axle with opposite-thread bolts. It is also mentioned that [[HordeOfAlienLocusts the Hive]] is unique among all known species in that it is able to digest proteins of either chirality.

* The pungently orange-scented solvent popular under various trade names as a household cleaner is the D-enantiomer of the hydrocarbon limonene. The R-enantiomer is also a solvent that can be used as a cleaner, but smells of pine. Upon learning this, some people suddenly realize the true but often-overlooked fact that pine and citrus are very similar scents.

Many 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 a lot 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'' multicellular organisms on Earth are made of L-(or levo-)amino acids.[[note]]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.[[/note]] 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:

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. There may be some mention of the fact that ethanol is a biologically interesting molecule 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 (assuming you have the right microbes).

* The Creator/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]].)]]
* An important plot point in Marti Steussy's ''Dreams of Dawn''. Juvenile (and not yet sapient) Kargan natives like the taste of terrestrial food, but it can cause their metamorphosis process to go fatally awry [[spoiler:thanks to some meddling by AbusivePrecursors]]. The side effects of Kargan food on terrestrial species likewise range from indigestion to fatalities. [[spoiler:Solved at the end by altering the colonists' biochemistry to match that of the native species, after much [[HeroicSacrifice trial and error]].]]
* In ''Literature/ThePentagonWar'', Centaurian metabolism is based around levulorotary glucose (instead of the dextrorotary glucose we Earth people use). Centaurian food has no nutritional value to humans, and can sometimes be downright poisonous to them -- and vice-versa.
* In the Creator/ArthurCClarke short story "Technical Error", an experimental superconducting power station accidentally inverts Richard Nelson so that all his body chemistry is opposite-handed. He needs to have special "left-handed" food synthesized for him, and since no one is sure if we've missed any essential micronutrients that would also need to be inverted for him, he figures his best option for long-term survival is to repeat the accident and try to re-invert himself.
* In the ''Literature/StarCarrier'' series, Osiris, a planet orbiting 70 Ophiuchi, is a rare garden world where humans can survive unprotected. However they have to grow their own food crops since the native life has the opposite chirality from Earth life and is therefore inedible.
** However, the planet Vulcan orbiting Epsilon Eridani A is even rarer since the local life has the exact same chirality as terrestrial life. Unfortunately, the same is true for the new aliens discovered in the fifth book, and these aliens are looking for some new prey to hunt and eat.

[[folder: Live Action TV ]]
* An episode of ''Series/BlackHoleHigh'' was actually called "Chirality," and introduced the concept in a chemistry class -- then used it as a justification for a PersonalitySwap episode.

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. There may be some mention of the fact that ethanol is a 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 (assuming you have the right microbes).

* The Creator/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 Creator/RobertLForward to Robert L. Backward.]]]]

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'' multicellular organisms on Earth are made of L-(or levo-)amino acids.[[note]]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.[[/note]] 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:

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 (assuming you have the right microbes).

* 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.

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.[[note]]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.[[/note]] 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:

* 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. As if that's not enough, the human body can sometimes metabolize a useful structure into its harmful mirror image. 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. The early testing of the compound was performed on just the desired enatiomer, but the mass-production synthesis method produced a racemic form. 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).

* In ''[[Literature/AliceInWonderland Through the Looking Glass]]'', 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'', Martin Gardner 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.

** 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 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.

** If a female Shepard romances her turian teammate Garrus, Dr. Mordin Solus warns her against swallowing turian semen.
** Also, if a male Shepard romances his quarian teammate Tali, Dr. Mordin Solus says; "Oral contact with tissue dangerous. Take precautions." This could be a warning against swallowing quarian vaginal fluids, advice to not let Tali swallow human semen, or both.

* The Creator/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.]]]]

* ''TourOfTheMerrimack'': The crew aren't worried about picking up any diseases in the Myriad because life on those worlds uses opposite-handed proteins, which are are incompatible with human biology. It's likened to attempting to attach a four-post wheel to a five-post axle with opposite-thread bolts. It is also mentioned that [[HordeOfAlienLocusts the Hive]] is unique among all known species in that it is able to digest proteins of either chirality.

* In the ArthurCClarke short story "Technical Error", an experimental superconducting power station accidentally inverts Richard Nelson so that all his body chemistry is opposite-handed. He needs to have special "left-handed" food synthesized for him, and since no one is sure if we've missed any essential micronutrients that would also need to be inverted for him, he figures his best option for long-term survival is to repeat the accident and try to re-invert himself.

* An episode of BlackHoleHigh was actually called "Chirality," and introduced the concept in a chemistry class -- then used it as a justification for a PersonalitySwap episode.

* In ''{{GURPS}} Time Travel'', this is one of the entries on the "something went wrong with our dimension-traveling device" chart.
* Many colony worlds in the ''[[TabletopGame/{{TwentyThreeHundredAD}} 2300 AD]]'' universe have dextro-based life. To get around this, human colonists sterilize large patches of ground and use "pay dirt" from Earth to set up a localized biosphere suitable for growing crops. On the other hand, many native creatures from dextro-worlds (most infamously [[EverythingIsTryingToKillYou Aurore]]) will take a bite out of humans or their livestock without worrying whether it will make them sick.

--> -- ''VideoGame/MassEffect2''

** Referenced darkly in Creator/AlanMoore's ''LeagueOfExtraordinaryGentlemen''; in a text feature in Vol. 2, it is revealed that Alice emerged from the Looking Glass world with her entire body mirror-reversed. As a result, she was unable to eat normal food, and ultimately starved to death.

[[folder: Literature ]]

* In the massively crossover fanfic ''Bring Me the Head of Harry Potter'', it's revealed that Voldemort used a spell that turned people inside out. Examining a battlefield long after the fact, Willow Rosenberg feels the earth's pain from wrong-chirality organic molecule poisoning.
* One ''Series/StargateSG1'' fanfic mentions a right-handed world being used as a prison planet. Plenty of oxygen, but if you escape the prison camp there's absolutely nothing to eat. Unless you [[spoiler: dismember the guards]].

* In 'The Boy Who Reversed Himself'' by Creator/WilliamSleator, the protagonists gain the ability to enter the fourth dimension and therefore end up reversed. They learn that mirror-ketchup is an extremely addictive drug.

* In the massively crossover fanfic Bring Me the Head of Harry Potter, it's revealed that Voldemort used a spell that turned people inside out. Examining a battlefield long after the fact, Willow Rosenberg feels the earth's pain from wrong-chirality organic molecule poisoning.