Dear list:
Collagen and spirals are chiral. All the abstrusities can be entered here, a nice illustration of the investigative process. I, for one, do not have the time, as having to do so will affect my sensibility. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3675869/ Best, Jerry R On Thu, Dec 14, 2017 at 2:27 PM, John F Sowa <[email protected]> wrote: > On 12/13/2017 7:56 AM, [email protected] wrote: > >> Peirce is referring to /organic/ compounds as “such active substances.” >> But I still don’t know what he’s referring to as “those substances which >> rotate the plane of polarization to the right or left.” What would those be >> called by chemists today? >> > > Many kinds of crystals and solutions rotate the plane of polarized > light. But organic molecules tend to be more complex than inorganic > molecules, and they frequently come in pairs that are identical, > except for *chirality* (left or right handedness). > > The formulas of the L- and R- versions are identical, but because of > the geometry of the molecules, they differ in exactly the same way as > the right and left hands. When light passes through solutions of those > molecules, it reacts differently with the two kinds, but the difference > is only detected when the light happens to be polarized. > > The two kinds of molecules are called *enatiomers* of each other. > See https://en.wikipedia.org/wiki/Enantiomer > > See below for an excerpt from the Wikipedia article about splitting > sucrose into *invert sugar*, a mixture of glucose and fructose. > > John > ___________________________________________________________________ > > From https://en.wikipedia.org/wiki/Inverted_sugar_syrup > > The term "inverted" is derived from the practice of measuring the > concentration of sugar syrup using a polarimeter. Plane polarized light, > when passed through a sample of pure sucrose solution, is rotated to the > right (optical rotation). As the solution is converted to a mixture of > sucrose, fructose and glucose, the amount of rotation is reduced until (in > a fully converted solution) the direction of rotation has changed > (inverted) from right to left. > > C12H22O11 (sucrose, Specific rotation = +66.5°) + H2O (water, no rotation) > → C6H12O6 (glucose, Specific rotation = +52.7°) + C6H12O6 (fructose, > Specific rotation = −92°) > > net: +66.5° converts to −19.65° (half of the sum of the specific rotation > of fructose and glucose) > > > ----------------------------- > PEIRCE-L subscribers: Click on "Reply List" or "Reply All" to REPLY ON > PEIRCE-L to this message. PEIRCE-L posts should go to > [email protected] . To UNSUBSCRIBE, send a message not to PEIRCE-L > but to [email protected] with the line "UNSubscribe PEIRCE-L" in the > BODY of the message. More at http://www.cspeirce.com/peirce-l/peirce-l.htm > . > > > > > >
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