LIPIDS Varied in structure Contain Carbon and hydrogen, and linked by non polar covalent bonds.

LIPIDS Many are insoluble in water- lack polar group Fat provides insulation and energy storage, cushions vital organs Helps keep water fowl afloat Repels water Animals use fat rather than glycogen for long term energy storage (fat stores more energy)

Fats Fats are triglycerides containing saturated fatty acids. (butter) Fat are two molecules linked Fatty Acids Glycerol

Glycerol Water soluble compound with three hydroxyl groups

Fatty Acids Long hydrocarbon chain with a carboxyl (acid) group at one end

Fatty Acids Most fatty acids contain 16-18 carbon atoms per molecule

Saturated fatty acids Have no double bonds between their carbon atoms Molecules are packed closely together

Saturated Animal Fats Associated with circulatory disorders Plant oils can be substituted for animal fats in the diet

Unsaturated fatty acids Have double bonds in the carbon chain where there are less than two hydrocarbons per carbon atom. Kinked structure prevents molecules packing tightly together.

Oils Oils are triglycerides with unsaturated fatty acids (corn oil) Fats of plants and fish are generally unsaturated They are built of one or more types of unsaturated fatty acids Liquid at room temperature Oils Olive oil, cod liver oil

Hydrogenated Vegetable Oils Unsaturated fats that have been synthetically converted to saturated fats by adding hydrogen (trans fats) Peanut butter, margarine are hydrogenated to prevent lipids from separating out in liquid form. (oil)

Trans Fat

Waxes Long chain of fatty acids bonded to a long chain of alcohol More hydrophobic Solid at room temperature High melting point Water proof Retards water loss in plants and animals Natural coating of fruit Resists degradation

Phospholipids Major component of the cell membranes Similar to fat but has only two fatty acids attached to glycerol Hydrocarbon tails are hydrophobic Phosphate group are hydrophilic

Phospholipids Arrange themselves in a double layer. Enables them to form an interface or separation between two solutions (interior and exterior of the cell)

Steroids Lipids characterized by a carbon skeleton consisting of four fused rings Different steroids vary in the functional groups attached to the rings

Cholesterol Steroid that is a common component of the animal cell membrane Precursor from which other steroids are synthesized Testosterone Estrogen

Cholesterol Crucial molecule in animals but high levels in the blood may contribute to atherosclerosis. Hardening of the arteries