Question

Show that a phosphatidic acid is chiral, even though none of its fatty acids are chiral. Where is the asymmetric carbon atom?

Short answer

The asymmetric carbon atom (chiral carbon) is marked with * in the structure which is linked to four different atoms or groups that proves phosphatidic acid as chiral.

Step-by-step solution

Chiral molecule

Molecules having exact mirror images of itself and has non- super imposable mirror image is known as a chiral molecule. Enantiomers or optical isomers are two mirror images of a chiral molecule.

Asymmetric carbon atom (chiral carbon)

An asymmetric carbon atom is the one in which the carbon atom is attached to four different types of atoms or groups.

Phosphatidic acid

Phosphatidic acids are the simplest form of phospholipids which is made up of glycerol esterified by two fatty acids and one phosphoric acid group.

Explanation

The asymmetric carbon atom (chiral carbon) is marked with * in the structure (shown in red). The carbon atom marked with (*) is linked to four different atoms or groups. Hence, it proves that the phosphatidic acid is chiral though none of its fatty acids are chiral.