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