"Cracking Chirality" from Chemistry Shorts™ explores how the essential molecules of life, like DNA, RNA, and proteins, acquired their homochiral structures and how magnetic rocks at the bottom of a prebiotic lake, may have set the stage for life as we know it.

In a mirror, our bodies appear symmetrical from the right to the left. But hold one hand on top of the other, rather than palm-to-palm, and you’ll notice that they are not in fact the same; they have a defined right- or left-handedness, or chirality. Look even deeper inside, at the molecular level, and you’ll find that many of the important molecules in our bodies are similarly right or left-handed, and exist in only one form or the other. We call this homochirality.

Chirality is the idea that some molecules come in two mirror-image configurations. Despite having the exact same chemical compositions, their physical structures are different. These left-handed and right-handed molecules can have different properties and functions. Understanding how chiral molecules function differently is essential to chemical synthesis and medicine. But it also holds a curious question about early life: why are the nucleic acids that hold genetic information in all of life right-handed, while the amino acids that they encode left-handed?

In "Cracking Chirality,” two Harvard University scientists, Dimitar Sasselov and Furkan Ozturk, present their exciting new findings: magnetized molecules found at the bottom of lakes on the primordial Earth may be the key to how important biological molecules crystallized and grew, tipping the scales from a 50-50 mixture of molecules to homochiral solutions made up of just one or the other. Their simple experimental setups, growing crystals on tiny magnetized plates, help provide a solution to an essential question about life itself that has plagued scientists for decades.

“Life's polymers from DNA, to RNA, to the proteins, cannot really function if they're a mess of left-handed and right-handed molecules. They have to be clearly homochiral. And you need to do something very special to break that symmetry. It is still a big mystery of how this happened at the origin of life. And our work is trying to answer that question.”
– Dr. Dimitar Sasselov in “Cracking Chirality.”

“Cracking Chirality” is targeted towards high school and college students, and can be used as a starting point for discussions around the chemical origins of life, molecular chirality, electron spin, magnetism, and more.

Learn about Dr. Sasselov’s work here: https://astronomy.fas.harvard.edu/peo...

Learn more about Chemistry Shorts™ and view companion classroom curriculum at www.chemistryshorts.org