Presentation on theme: "Ch. 5.3: LIPIDS Objectives:"— Presentation transcript:
1 Ch. 5.3: LIPIDS Objectives: Identify a general characteristic of lipids.Describe the structure and function of fats.Describe the structure and function of steroids.Vocabulary:LipidHydrophobicFatSaturated fatUnsaturated fatSteroidCholesterol
2 5.3: Lipids FUNCTIONS Store energy Chemical signals to cells Waxes or oils or fatsHYDROPHOBIC!Also made of C, H & O, but lower proportion of oxygenLipids store more energy than carbohydrates because they have twice as many energy rich (C-H) bonds than carbohydrates.1 Lipid = 3 fatty acids + 1 glycerol molecule (monomers)Example: Triglyceride (polymer): Composed of 3 fatty acid molecules joined to 1 Molecule of alcohol glycerol.FUNCTIONSStore energyChemical signals to cellsBoundary to water in cells (IN CELLMEMBRANE)Cushion organs
3 A fatty acid is a long hydrocarbon chain with a carboxyl (acid) group at one end. The Carboxyl End (HEAD) POLAR and HYDROPHILIC.The Hydrocarbon End (TAIL) NONPOLAR and HYDROPHOBIC.Saturated fatty acids have no double bonds between their carbon atoms.Unsaturated fatty acids have double bonds in the carbon chain.
4 5.3: LIPIDSSaturated-carbons are joined by all single bonds; room temp.;Ex: animal fats (bacon fat, etc.), cheeses, butternot healthy (raise cholesterol)Unsaturated (mono or poly) –2 carbons are joined by a double bondUsu. room temp.Derived from plants or fishEx: olive oil, nuts, fish oilsHealthier fatsPolyunsaturated-carbons have many double bonds
7 5.3: STEROIDS Steriod - Lipid molecule with 4 fused carbon rings. Different functional groups attach to rings for different results.Ex: Testosterone vs. Estrogen (HORMONES); Cortisol, AdrenalineAct as chemical signals or messengers to cells.Cholesterol: in cell membranes. Over abundance can clog arteries.
8 5.3: PhospholipidsPHOSPHOLIPIDS - TWO Fatty Acids joined by a Molecule of Glycerol. Called a LIPID BILAYER and forms a barrier between the inside and outside of the Cell.