Catabolism of phospholipids in tissues: enzymes, end products (HFAs, glycerol, amino alcohol, and phosphoric acid). Biosynthesis of glycerophospholipids: substrates, de novo and salvage pathways (biosynthesis scheme), enzymes. Regulation of PL synthesis and breakdown in tissues. Clinical aspects of membrane lipid metabolism: role of lecithin (dipalmitoylphosphatidylcholine). Structure of surfactant. Biochemical basis of respiratory distress syndrome; multiple sclerosis, lysosomal diseases, antiphospholipid syndrome. Answer in biochemistry and also give schemes if required