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Lipids~
- 1. Triglyceride & Phospholipids -Structure & Formation -Function
- 2. LIPIDS? What are they? A group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E, and K), triglycerides, phospholipids, and others. Why a group? -Insoluble in water(polar solvents) but soluble in organic solvents(non- polar solvents) -Non-polar in nature
- 3. LIPIDS? Functions: Storing energy, signalling, acting as structural components of cell membranes, insulating and protecting internal organs FYI: Have applications in the cosmetic and food industries as well as in nanotechnology. ;D
- 4. TRIGLYCERIDE-STRUCTURE 1 glycerol + 3 fatty acids The hydrocarbon tails of fatty acids are hydrophobic
- 6. TRIGLYCERIDE-F O R M A T I O N Formed by Condensation reactions Hydroxyl group of glycerol reacts with carboxyl group of fatty acids
- 7. TRIGLYCERIDE-FORMATION The reaction gives formation to 3H2O molecules and 1 Triglyceride molecule Glycerol and fatty acids joined by Ester bonds (Esterification)
- 8. TRIGLYCERIDE-FORMATION http://nutrition.jbpub.com/resources/animations.cfm?id=10 https://smartsite.ucdavis.edu/access/content/user/00002950/bis10v /media/ch02/triglyceride.html http://www2.nl.edu/jste/lipids.htm (condensation) The reverse happens for the hydrolysis reaction - a molecule of water is added to each ester bond to break them apart and the triglyceride splits up into three fatty acids and one glycerol molecule.
- 9. TRIGLYCERIDE-FUNCTION Fat and liver cells can synthesize & store triglycerides. When body requires fatty acids as an energy source, glucagon will then signal the breakdown of triglycerides by hormone-sensitive lipase to release free fatty acids. Brain cannot utilize fatty acids as an energy source (unless converted to a ketone), the glycerol component of triglycerides can be converted into glucose, via gluconeogenesis, for brain fuel when it is broken down. Fat cells may also be broken down for that reason, if the brain's needs ever outweigh the body's.
- 10. TRIGLYCERIDE-FUNCTION Cannot pass through cell membranes freely. Special enzymes on the walls of blood vessels called lipoprotein lipases must break down triglycerides into free fatty acids and glycerol. Fatty acids can then be taken up by cells via the fatty acid transporter (FAT). (Movement in/out of cells) Completely hydrophobic so they cannot integrate into membranes. Hence, triglycerides bind to specialized proteins called lipoproteins to enable them to travel through the blood. (Movement in blood)
- 11. Phospholipids-Structure 2 fatty acids, 1 glycerol unit, 1 phosphate group & 1 polar molecule Polar head: Phosphate group along with the glycerol group make the head of the phospholipid Hydrophilic, Non-polar tail: The fatty acid tail which is Hydrophobic. Thus phospholipids are amphipathic: a molecule with a polar end and a hydrophobic end. E.g.: Phosphatidylethanolamine Phosphatidylinositol Phosphatidylserine lecithin Plasmalogens Sphingomyelins
- 12. Phospholipids-Formation As a triprotic acid (i.e it has three acidic functions on the phorphorus atom) the phosphate group attached to the glycerol has the potential to form ester links with a variety of other molecules such as carbohydrates, choline, inositol and amino acids.
- 13. Phospholipids-Bilayer Amphipathic nature plays a critical role. When in aqueous solution, phospholipids will orient themselves into a bilayer in which the nonpolar tail region faces the inner area of the bilayer. The polar head region faces outward and interacts with the water. In addition they may also sometimes form micelle, another type of self arrangement
- 15. Phospholipids-Function Phospholipids play multiple roles in cells in forming the permeability barrier of the cell membrane and intracellular organdies, in providing the supporting matrix and surface for many catalytic processes, in actively participating in signal transduction in response to both external and internal stimuli, and in providing precursors for signalling processes and macro molecular synthesis.
- 16. Phospholipids-Function Plasma membrane of cells-a semipermeable phospholipid layer, able to control movement of substances in and out of cell. It also creates a “wall” separating the cell contents and exterior surrounding fluid. Semi-permeable nature of the membrane allows the cell to maintain the composition of the cytoplasm independent of the external environment. Allows cells to change shape due to physical constraints or changing cellular volumes. Free diffusion of some small molecules such as oxygen, carbon dioxide, and small hydrocarbons, but not charged ions, polar molecules or other larger molecules such as glucose.