University:
Liberty University
Course:
BIOM 500 | Introduction to Biomedical Sciences
Academic year:

2024
Views:

326

Pages:

6
Author:

Sheha A.

Absorption of Lipids The water-soluble products of lipid digestion that can directly enter the portal vein and be taken to the liver and immediately utilized for energy. Water-insoluble products like 2-monoglycerides, long-chain fatty acids, and small amounts of cholesterol, phospholipids, and lysophospholipids are incorporated into bile acid micelles and absorbed into the intestinal wall. Metabolism of Lipids Introduction Fats are stored in the adipocyte as triglycerides. Triglycerides upon oxidation yield more energy than that of carbohydrates. For complete oxidation, a molecule of triglyceride on hydrolysis yields glycerol and 3 fatty acid molecules. Glycerol Glycerol and fatty acids enter the blood stream. Fatty acids are picked up by the tissues of liver, kidney, lungs, muscle, and adipose tissue for energy. Glycerol is picked up by the liver, kidney, and intestinal mucosa for oxidation. Lipolysis Complete degradation of triacylglycerol by lipase gives glycerol and three fatty acids. This process is called Lipolysis. Lipase acts as the lipolytic enzyme. Fate of Glycerol Glycerol is released by lipase action and then phosphorylated by glycerol kinase. The resulting glycerol-3-phosphate is oxidized to dihydroxyacetone phosphate by glycerol-3-phosphate dehydrogenase. The glycolytic enzyme phosphohexose isomerase converts the compounds to glyceraldehyde-3-phosphate which is then oxidized by glycolysis. Fate of Fatty acid: Fatty acids are oxidized to acetyl CoA. Acetyl CoA is then oxidized to CO2 via TCA cycle, resulting in further energy conservation. In liver, Acetyl CoA can be converted to ketone bodies, which is exported to the brain and other tissues when glucose is not available.