View Single Post
  #10  
Old January 28th 18, 11:48 AM posted to sci.astro.research
Steve Willner
external usenet poster
 
Posts: 1,172
Default Astronomy and Biology

[I thought I'd replied before, but it seems not to have gotten
through. Apologies if it shows up twice.]

[[Mod. note -- I don't recall seeing it. -- jt]]

In article ,
Martin Brown writes:
Not sure you need to use chiral labelled reagents.

You could feed the critters a racemic mixture and then measure any
change in the angle of rotation of plane polarised light if there was
any difference in the rate of reaction for the two forms.


Sorry, but I can't visualize how that would work. What would be
needed to prepare the sample? Viking had a labeled release
experiment (which showed positive results based on pre-flight
criteria), and a similar experiment with chiral reagents should be
only a little more complex.

I suspect there may well be some abiotic reactions on clay surfaces that
do show a preference for handedness if that is how life got started.


Have those been seen anywhere?

I think the preferred names are down to IUPAC.

Enantiomers are strictly non superposable mirror images of each other
whilst (dia)stereoisomers can include other things as well.
http://goldbook.iupac.org/html/D/D01679.html
Still chiral molecules but not related as exact mirror images.


Thanks! As far as I can tell, "stereoisomers" is the general term,
which includes both enantiomers and diastereoisomers. The latter
have more than one stereocenter and are mirror images in some but not
all. I've learned something.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA