enantiomeereissä

Enantiomeereissä refers to enantiomers, which are a specific type of stereoisomer. Stereoisomers are molecules that have the same chemical formula and the same sequence of bonded atoms but differ in the three-dimensional orientation of their atoms in space. Enantiomers are a pair of stereoisomers that are non-superimposable mirror images of each other. This means that if you were to hold one enantiomer up to a mirror, the reflection would look exactly like the other enantiomer, but you could not perfectly align them by rotating them in space.

The term "enantiomer" comes from the Greek words enantios, meaning "opposite," and meros, meaning "part." This aptly describes their relationship as opposite, yet related, molecular forms. A molecule that is chiral possesses the property of being enantiomeric. Chirality is often described by analogy to human hands; your left hand and right hand are mirror images, but they cannot be perfectly superimposed onto each other.

Enantiomers have identical physical properties such as melting point, boiling point, and density. However, they differ in their interaction with plane-polarized light; one enantiomer will rotate the plane of polarized light in one direction (dextrorotatory, indicated by a '+' sign or 'd-'), while the other enantiomer will rotate it by the same magnitude but in the opposite direction (levorotatory, indicated by a '-' sign or 'l-'). This property is known as optical activity.

In chemistry and biology, enantiomers can exhibit significantly different properties, especially in biological systems. Enzymes and receptors are chiral, meaning they can distinguish between enantiomers. This difference is crucial in pharmacology, as one enantiomer of a drug might be therapeutically active, while the other might be inactive or even harmful.