Packet #10 Campbell—Chapter #5 Lipids Packet #10 Campbell—Chapter #5

Introduction Contain carbon, hydrogen and oxygen Does not contain as many oxygen molecules as carbohydrates Formed via a condensation reaction and broken apart via hydrolysis 7/21/2019 5:43:35 PM

Functions of Lipids Energy Storage Structural Support Insulation Fats are stored for future energy use Structural Support Phospholipids Critical component of the cell membrane Insulation Especially useful where hair and feathers are of little use Example Underwater Blubber in whales Waterproofing Waxes Leaf cuticles are made of waxes Secreted from sebaceous glands of the skin Functions of Lipids Energy Storage Structure Insulation Waterproof 7/21/2019 5:43:35 PM

Components of Lipids Lipids are composed of two parts Glycerol Head Hydrophilic Fatty acids Tail Hydrophobic Some lipids have one of the fatty acids replaced by phosphoric acid These are called phospholipids Very important component of the cell membrane Lipids Head (Hydrophilic) Glycerol Organic Molecule Tail (Hydrophobic) Fatty Acids 7/21/2019 5:43:35 PM

Glycerol A syrupy, sweet, colorless or yellowish liquid, C3H8O3, obtained from fats and oils as a byproduct of saponification Glycerol is used as a solvent, an antifreeze, a plasticizer, a sweetener Glycerol is used in the production of dynamite, cosmetics, liquid soaps, inks, and lubricants. A reaction in which an ester is heated with an alkali, such as sodium hydroxide, producing a free alcohol and an acid salt, especially alkaline hydrolysis of a fat or oil to make soap.

Fatty Acid Tails Chain of carbon and hydrogen joined together.

Fats & Oils

Fats & Oils I Chemically, fats and oils are triglycerides. Simple lipids Store energy Composed of glycerol and three fatty acid chains. Triglycerides (at room temperature) Solid Fats Liquid Oils

Fats & Oils II Saturated Fats vs. Unsaturated Fats Saturated A molecule that has only single bonds Found largely in animals Unsaturated A molecule that has one or more multiple bonds Largely comes from plants Better for one’s health because the ”kinks” prevent the fat molecules from packing closely together. Helping reduce heart disease 7/21/2019 5:43:35 PM

Fats & Oils III—Kinks

Phospholipids

Phospholipids Found at the surface of cells Four main components Organic molecule PO4 {Phosphate/Phosphate Group} Replaces one of the fatty acid tails Glycerol Fatty acids Two 7/21/2019 5:43:35 PM

Phospholipid Bilayer Phospholipid bilayer is a series of phospholipids that are found at the surface of cells and helps make up the cell membrane.

Phospholipid Bi-Layer More to come in future packets.

Other Classes of Lipids

Other Classes of Lipids A number of lipids are not based on the glycerol-fatty acid structure. However, because they are largely composed of carbon and hydrogen and are non-polar, these molecules are still classified as lipids. Carotenoids Light absorbing pigments Beta carotene Steroids Cholesterol Cell signals Hormones Vitamins** Vitamin A is formed from beta carotene in green and yellow vegetables Waxes Repels water on plants and animals Other Classes of Lipids Carotenoids Steroids Vitamins Waxes

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