Critical Role of Mitochondrial Fatty Acid Metabolism in Normal Cell Function and Pathological Conditions Fatty Acid Metabolism Concise Medical Knowledge Short Note On Carnitine Shuttle: Fatty acids are oxidized in mitochondria, and synthesized in the cytoplasm. Long chain fatty acids must form an active intermediate, fatty acyl CoA, before being oxidized inside mitochondria. Catherine Translating the basic knowledge of mitochondrial functions to metabolic therapy: role of L carnitine Translational Research Role of L carnitine in the transportation of long chain fatty acid across the mitochondria membrane.