Chirality
College/University
Definition
A property of a molecule that is not superimposable on its mirror image, much like left and right hands. Chiral molecules exist as two mirror-image forms, which can behave very differently in biological systems.
Worked examples
Your left and right hands are chiral — they are mirror images but you cannot rotate one to match the other perfectly.
This everyday example shows chirality: identical shape but impossible to superimpose.
Lactic acid exists as L-lactic acid (in muscles) and D-lactic acid (in some bacteria) — mirror-image molecules with different biological roles.
Two chiral forms of the same molecule can interact very differently with enzymes and receptors.
Common mistakes
- A molecule is chiral if it has a mirror image. → A molecule is chiral if it is not superimposable on its mirror image. Every molecule has a mirror image; only non-superimposable ones are chiral.
- Chiral molecules always have the same properties as their mirror images. → Chiral mirror images (enantiomers) can have very different biological activity. One enantiomer may be therapeutic while its mirror image is inactive or even harmful.
- Only complex molecules with many atoms can be chiral. → Even small molecules like lactic acid or amino acids can be chiral. Chirality depends on arrangement around a central atom, not overall size.
Where you'll use it next
You'll use chirality when studying stereochemistry and organic reactions, understanding drug design and pharmacology, and exploring how enzymes recognize specific molecule shapes in biochemistry.
Found in 1 StudyPug lesson
Drawing Enantiomers: Mastering Isomerism and Stereochemistry
UniversityUniversityOrganic Chemistry
Unlock the secrets of molecular structures! Learn how to draw enantiomers and understand isomerism, stereochemistry, and chirality. Boost your organic chemistry skills for better drug design and material creation.
See also
Reviewed by Pat Cheng, M.Ed. — StudyPug Curriculum Lead · Last updated June 6, 2026