The document discusses acylglycerols (AG), which are the major lipids in the body. Some key points: - Phospholipids and sphingolipids are major lipid components of cell membranes and some have specialized functions like lung surfactant. - Fatty acids can be incorporated into triacylglycerol for energy storage or into phospholipids to make membranes. - Triacylglycerols (TAG) are biosynthesized through a three step process: 1) synthesis of glycerol phosphate, 2) conversion of fatty acids to an activated form, and 3) synthesis of TAG molecules from glycerol phosphate and fatty acyl CoA. -

1. Department of Biochemistry, Nepalgunj Medical College, Nepal
Saturday, July 2,
2016
Rajesh Chaudhary
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2. Biomedical importance of Acylglycerols
(AG)
 The majority of lipids in our body are acylglycerols.
 Phospholipids & sphingolipids are major lipid components of cell
membranes.
 Some phospholipids have specialized functions.
1. Dipalmitoyl lecithin: major component of lung surfactant, which is
lacking in respiratory distress syndrome of newborn.
2. Inositol phospholipids: … in cell membrane acts as precursor of
hormone second messengers, platelet activating factor.
3. Glycocalyx: … of cell surface are important cell adhesion and cell
recognition factors, acts as receptors for bacterial toxins.
Saturday, July 2,
2016
Rajesh Chaudhary
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3. Either ingested or synthesized, fatty acids have just two
fates:
1. Incorporation into triacylglycerol for storage of
metabolic energy.
2. Incorporation into phospholipid components of
membranes making glycerophospholipids.
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2016
Rajesh Chaudhary
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4. Biosynthesis of triacylglycerols (TAG)
1. Synthesis of glycerol phosphate.
2. Conversion of free fatty acids to its activated
form.
3. Synthesis of molecules of TAG from glycerol
phosphate and fatty acyl CoA.
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2016
Rajesh Chaudhary
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5. 1. Synthesis of Glycerol phosphate
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2016
Rajesh Chaudhary
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The glucose transporter (GLUT-4) in adipocytes are insulin-dependent. Thus, when
plasma insulin is down, adipocytes have limited capabilities to synthesize glycerol
phosphate and ultimately TAG.

6. 2. Conversion of free fatty acids to its
activated form
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2016
Rajesh Chaudhary
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Figure. Assembly and secretion of chylomicrons by intestinal mucosal cells.

7. 3. Synthesis of molecules of TAG from
glycerol phosphate and fatty acyl CoA.
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2016
Rajesh Chaudhary
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8. 3. Synthesis of molecules of TAG from
glycerol phosphate and fatty acyl CoA.
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9. Triacylglycerol synthesis is regulated by
Insulin
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2016
Rajesh Chaudhary
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10. Metabolic changes in T1DM & T2DM
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11. Metabolic changes in T1DM & T2DM
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12. Triacylglycerol cycle12

13. Fates of TAG in the liver and adipose
tissue
In white adipose tissue, TAG is stored in a nearly
anhydrous form as fat droplets in the cytosol of the cells.
Little TAG is stored in liver while most is packaged with
other lipids and Apo proteins to form lipoprotein particles
called VLDL.
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2016
Rajesh Chaudhary
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14. Saturday, July 2,
2016
Rajesh Chaudhary
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