Structural Lipids.pptx

Structural Lipids - Phospholipids, Glycolipids. Phospholipids types - Glycerophospholipids, Sphingolipids, and their importance in plant and animal cells. Examples for phospholipids and their structure. Sphingomyelin, ceramide, lecithin, cephalin.

1. Structural Lipids - Glycolipids & Phospholipids - Types and Importance Jasmine Juliet Teaching Assistant Biochemistry, ACRI, Madurai.

2. STRUCTURAL LIPIDS Phospholipids and glycolipids are important structural lipids and are constituents of biological membranes .

3. Phospholipids

4. Phospholipids - Introduction LIPIDS: Lipids are macrobiomolecule that are insoluble in water, but soluble in organic solvents like ether, benzene, chloroform etc. PHOSPHOLIPIDS: Phospholipids   are a class of lipids  whose molecule has a hydrophilic "head" and hydrophobic "tails".  Phospholipids are compound lipids contain fatty acids, alcohol, phosphoric acid and nitrogenous base.

5. Phospholipids - Structure

6. Phospholipids - Introduction   Phospholipids are the major component of biological membranes. Phospholipids are compound lipids contain fatty acids, alcohol, phosphoric acid and nitrogenous base. There are two classes of phospholipids Glycerophospholipids – contain glycerol as alcohol Sphingophospholipids - contain sphingosine as alcohol

7. Phospholipids - Glycerophospholipids Glycerophospholipids are the major lipids that occur in biological membranes. They contain glycerol, fatty acids, phosphoric acid and a nitrogenous base .

8. Glycerophospholipids Glycerophospholipids are the major lipids that occur in biological membranes. They contain glycerol , fatty acids, phosphoric acid and a nitrogenous base.

9. The general formula of glycerophospholipids is :

10. Glycerophospholipids Usually C-1 contans a saturated fatty acid while C-2 contains an unsaturated fatty acid. The simplest of phospholipids is phosphatidic acid. It contains a glycerol, fatty acids and phosphate.

11. Phospholipids - Types Depending on the alcoholic residue attached , they are named as: Phosphatidyl choline (lecithin), Phosphatidyl ethanolamine ( cephalin ), Phosphatidyl serine, Phosphatidyl inositol , Phosphatidyl glycerol and Diphosphatidyl glycerol ( cardiolipin ).

12. Phospholipids - Types Lecithins are the most abundant group of phospholipids in the cell membranes and have metabolic and structural functions. Dipalmitoyl lecithin is an important surface active agent in lungs.

13. Phospholipids - Types

14. Phospholipids - Types Cephalins are also membrane phospholipids and have the base ethanolamine. Phosphatidylinositol is involved in signal transduction. Cardiolipin was first isolated from heart muscle. It consists of two phosphatidic acid held by an additional glycerol. It is an important component of inner mitochondrial membrane.

15. Phospholipids - Types Phosphatidylglycerol is a major phospholipid in thylakoid membrane of chloroplast. Phosphatidyl serine is a minor component of most membranes. It is found to take part in cell signaling and in apoptosis.

16. Phospholipids – Functions In association with proteins, phospholipids form the structural components of membranes and regulate membrane permeability. Phospholipids (lecithin, cephalin , and cardiolipin ) in the mitochondria are responsible for maintaining the conformation of electron transport chain components and thus cellular respiration.

17. Phospholipids – Functions Due to their amphipathic nature, phospholipids can combine with polar and non-polar compounds in the cell. Phospholipids participate in the absorption of fat from the intestine . Phospholipids are essential for the synthesis of different lipoproteins and thus participate in the transport of lipids.

18. Phospholipids – Functions Arachidonic acid liberated from phospholipids serves as a precursor for the synthesis of eicosanoids (prostaglandins, prostacyclins , thromboxanes , etc.) Dipalmitoyl lecithin is an important lung surfactant . Cephalins participate in blood clotting .

19. Phospholipids – Functions Phospholipids are essential components of bile where they act as detergents and helps in solubilization of cholesterol. Phosphatidyl inositol is involved in signal transmission across membranes.

20. Sphingophospholipids Sphingophospholipids contain phosphate and fatty acid attached to the alcohol, sphingosine or its derivatives ( dihydrosphingosine , phytosphingosine ). Eg : Sphingomyelins

21. Sphingophospholipids

22. Sphingophospholipids The fatty acids are attached through an amide linkage rather than the ester linkage. The base present is normally choline . Sugar residue may also be linked to phosphoric acid group.  

23. Sphingophospholipids When fatty acid and sphingosine is linked by amide bond, a ceramide is formed. Ceramide is the fundamental unit in all sphingolipids . Sphingomyelins are found in large amount in the brain and nerve tissues. Sphingophospholipids are also found in the seeds of several plant species.

24. GLYCOLIPIDS Glycolipids contain an alcohol ( sphingosine or glycerol), fatty acid and a monosaccharide . They are O-glycosides of either sphingosine or glycerol derivative. The commonly attached monosaccharides are D-glucose, D- galactose or N-acetyl D- galactosamine .

25. GLYCOLIPIDS Monogalactosyl diglycerides and digalactosyldiglycerides have been shown to be present in many higher plant tissues especially in chloroplast membrane. Glycolipids present in animal cells help in cell to cell communication