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Monday, June 19, 2017

Celebrate Cephalopod Week: Squid, Octopuses, Cuttlefish, and Nautiluses

       It's the second annual Cephalopod Week.  How can you not love a creature whose name means head-foot? Cue the "open mouth/insert foot jokes."

        How will you celebrate?!

      Cuddle a cuddlefish with its 'W'-shaped eyes?

      Ogle an octopus, like this one from the Maldives? 

      Swim with a squid, like this technicolored fellow?

       Net with a nautilus?

      Come on out of your shell and join the Cephalopod Party. Cephalo off to Buffalo?

Do you have a favorite cephalopod. . .and why? {I like them all; off to celebrate!}

Sunday, June 11, 2017

Let's Make This Post go Chiral: From Amino Acids to Zwitterions

      A recent RadioLab story inspired this week's post on chirality; we certainly hope this Partial Ellipsis of the Sun post goes chiral

      Chirality is the property of having a structure that is non-superimposable on its mirror image. The term chirality is derived from the Greek word for hand, χειρ (kheir).

      The mirror images of a chiral molecule/ion are called enantiomers or optical isomers.

     Most DNA (B-DNA) double-helix molecules are right-handed, though there are some DNA molecules called Z-DNA that are left-handed. Thus, the labels on the following diagram are correct for most DNA.

     The chirality of molecules has much importance in biomolecules and in pharmaceuticals where left-handed molecules are more often the norm; the toxic version in right-handed molecules (like thalidomide) are the abnormal and destructive ones. Ironic that the handedness of molecules caused so much hand/arm (and foot/leg) deformities in thalidomide babies.

      On earth, amino acids characteristic of life are all left-handed in shape (Levo), and cannot be exchanged for their right-handed (Dextro) counterparts.  However, all sugars characteristic of life on Earth are right-handed, hence, dextrose. The opposite hands for both amino acids and sugars exist in the universe, but they just aren’t utilized by any known biological life form.

      A zwitterion is a neutral molecule with both positive and negative electrical charges. The image on the right (above) is a zwitterion.

     Thus, amino acids in earth's life forms go left, sugars go right, DNA double helixes go right. What's the Chirality Winner? ;-)

Please hand in your Chiral thoughts. . .

(And here's Telluride, CO, this weekend to clear your head and hands from all those chiral molecules):