Final answer:
Enantiomers are non-superimposable mirror images with identical molecular formulas but different three-dimensional orientations. To draw them, identify chiral centers and illustrate two mirror-image molecular structures that cannot be superimposed on each other.
Step-by-step explanation:
Enantiomers are stereoisomers that are related to each other as non-superimposable mirror images. They have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in space. This three-dimensional arrangement is crucial because it can affect the molecule's chemical properties and biological interactions. To draw a pair of enantiomers, you must first identify any chiral centers—typically a carbon with four different groups attached. Then, you draw two configurations of the molecule, each being the mirror image of the other, ensuring they cannot be superimposed onto one another.
For example, D-glucose and L-glucose are enantiomers with each form having the hydroxyl groups (-OH) oriented differently around the chiral carbon atoms. In proteins, we generally find L-amino acids like L-alanine, whereas D-amino acids like D-alanine can be found in bacterial cell walls. These small differences in spatial arrangement lead to significant differences in their biochemical roles and effects.