Prostaglandins are derived from which parent molecule?

• A. Arachidonic acid
• B. Linoleic acid
• C. Palmitic acid
• D. Myristic acid

Answer: (A)

Prostaglandins come from arachidonic acid, a 20-carbon polyunsaturated fatty acid stored in membrane phospholipids. When cells are activated, phospholipase A2 releases arachidonic acid, which is then converted by cyclooxygenase enzymes into prostaglandin G2 and H2. These intermediates are further transformed by specific synthases into the various prostaglandins (such as PGE2, PGI2, PGD2, and others). Linoleic acid is an essential fatty acid that can be converted downstream to arachidonic acid, but prostaglandins are produced from arachidonic acid itself, not directly from linoleic acid. Palmitic and myristic acids are saturated fats not involved in this pathway.