molecule diagram

Biomolecules are Left or Right Handed

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Confronting risks of mirror life
All known life is homochiral. DNA and RNA are made from “righthanded” nucleotides, and proteins are made from “left-handed” amino acids. Driven by curiosity and plausible applications, some researchers had begun work toward creating lifeforms composed entirely of mirror-image biological molecules. Such mirror organisms would constitute a radical departure from known life, and their creation warrants careful consideration.

Left or right handed biomolecules
Many biomolecules come in two versions that are each other's mirror image, like a left and a right hand. Cells generally use the left-hand version of amino acids to produce proteins, and uptake mechanisms were thought to share this preference. Scientists have now shown that a prokaryotic transport protein can transport both versions of the amino acid aspartate with equal efficiency.

Why are all proteins ‘left-handed’? New theory could solve origin of life mystery
Experiments suggest chemical reaction rates explain how amino acid pairs, and perhaps DNA and RNA, get biased toward one handedness.