Q.52 In a typical oil-seed crop, the matured seeds are enriched with
(A) Phospholipid (B) Galactolipid (C) Neutral lipid (D) Sphingolipid
Correct Answer: (C) Neutral lipid
In typical oil-seed crops like soybean, rapeseed, and sunflower, matured seeds accumulate neutral lipids primarily as triacylglycerols (TAGs), comprising 90%+ of total seed lipids for energy storage and oil extraction.
Option Analysis
(A) Phospholipid: Incorrect. Phospholipids form cell membranes (minor component, ~2-5% of seed lipids); not primary storage form in oilseeds despite extraction as lecithin byproducts.
(B) Galactolipid: Incorrect. Galactolipids dominate chloroplast membranes in green tissues; absent or trace in mature oilseeds lacking photosynthetic plastids.
(C) Neutral lipid: Correct. Triacylglycerols (TAGs: glycerol + 3 fatty acids) form oil bodies, enabling 40-60% oil content by dry weight in commercial oilseeds.
(D) Sphingolipid: Incorrect. Sphingolipids occur in plasma membranes (~1% lipids); structurally complex signaling lipids, not energy-dense storage compounds.
In a typical oil-seed crop, the matured seeds are enriched with neutral lipid as triacylglycerols (TAGs), enabling high oil yields (40-60% dry weight) critical for edible oils and biodiesel.
Lipid Classes in Oilseeds
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Neutral lipids (90%+): TAGs stored in oil bodies; oleic/linoleic acids predominant.
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Polar lipids (5-10%): Phospholipids (lecithin), galactolipids (chloroplasts).
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Minor lipids: Sphingolipids, sterols, tocopherols.
Oil Accumulation Process
TAG biosynthesis peaks during mid-to-late seed maturation:
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Acetyl-CoA → fatty acids in plastids.
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ER: DGAT1/2 acylates DAG → TAG.
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Oil bodies coated with oleosins prevent coalescence.
Commercial Implications
Rapeseed (44% oil), sunflower (50%), soybean (20%) all prioritize neutral lipid storage. Breeding targets DGAT genes to boost TAG content 5-10%.
