Lipids Hydrophobic Not considered polymers Why not Fats

Lipids Ü Hydrophobic Ü Not considered polymers Ü Why not? Ü Fats aka triglycrides Ü Consist of glycerol and 3 fatty acids Ü Fatty acids Ü Variable length hydrocarbon cains Ü Chains are non-polar Ü Saturated Fatty acids Ü No double bonds Ü Solid at room temp Ü Linked to cardiovascular disease Ü Produced by animals Ü Butter and Lard

Lipids Ü Unsaturated Fatty Acids Ü Have double bonds make kinks Ü STRUCTURE determines FUNCTION Ü Liquid at room temperature Ü Commonly produced by plants Ü Corn and olive oil Ü Functions of fatty acids Ü Energy storage, 2 x cal/g than carbohydrates Ü Protection and Insulation (adipose tissue)

Fatty Acid

Concept Check Ü What is the difference in the hydrocarbon tails in the all natural vs creamy Skippy peanut butter. Ü Why do plants have large energy stores in the form of starch but animals have compact energy stores in fat? Ü Why have seals and whales evolved thick layers of adipose tissue?

Phospholipids Ü Cell membrane Ü Phosphate head Ü Glycerol backbone Ü Hydrocarbon tails Ü Form Bilayer

Phospholipid Structure

Phospholipid Bilayer

Phospholipids & Steroids Ü What kind of viscosity does a phospholipid bilayer have? Ü What does this mean for cell signaling Ü What about cell motility Ü STERIODS Ü 4 rings fused together Ü Cholesterol, common component of cell membranes Ü Estrogen & testosterone: steroid hormones