Arachidonic acid, the precursor for all eicosanoids, is a 20-carbon polyunsaturated fatty acid that humans can synthesize only if the diet supplies:

• A Linoleic acid ✓
• B Palmitic acid
• C Oleic acid
• D Docosahexaenoic acid

Explanation

Humans lack desaturase enzymes beyond the delta-9 position, so linoleic acid (18:2, omega-6) is essential; elongation and delta-6 then delta-5 desaturation convert it to arachidonic acid (20:4). Oleic and palmitic acids are nonessential and cannot restore the omega-6 double bond pattern. Docosahexaenoic acid is itself an omega-3 derivative of alpha-linolenic acid, not a source of the omega-6 arachidonate backbone.

Reference: Harper's Illustrated Biochemistry, 31st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.