 DNA double helix is chiral (as any kind of helix is chiral), and B-form of DNA shows a right-handed turn.Sometimes, when two enantiomers of a compound found in organisms, they significantly differ in their taste, smell and other biological actions.For example, (+)-limonene found in orange (causing its smell), and (–)-limonene found in lemons (causing its smell), show different smells due to different biochemical interactions at human nose.