Lipids!

Lipids… We will focus on two kinds: fatty acids and phospholipids. ◦ Others are waxes and steroids No real monomers or polymers

Fats Glycerol + 3 fatty acid chains Fatty acid chains are non-polar  why oil and water separate!

Why are Fats important? Energy storage. Stores twice as much energy as polysaccharides. ◦ More compact than carbohydrates also so take up less space in the body. ◦ Hydrocarbon chains are rich in energy. Insulation. ◦ Fat protects internal organs from pressure or shock.

Saturation of fats – refers to structure of hydrocarbon chain Saturated ◦ No double bonds  as many C-H bonds as possible. More energy than unsaturated fats. ◦ Animal fats ◦ Solid at room temperature (ex: butter) ◦ Pack tightly together  can form clumps that clog arteries which is why saturated fat is not good for you.

Unsaturated Fats At least one double bond between carbons formed by the removal of H  less energy than saturated fats. But they don’t clump together! Fats of plants and fishes (olive oil, cod liver oil) Liquid at room temp = oil

Phospholipids! Glycerol + 2 fatty acid chains + Phosphate group. “Head”-Phosphate group negatively charged, hydrophilic ( water) “Tail”-Fatty acid chains hydrophobic ( water) So, when placed in water, phospholipids assemble so that heads face out toward water, tails protected.

Why are phospholipids important? Our cells are mostly water—how is water held in the cell? Self-assemble to create cell membranes. This is called the lipid bilayer. Certain things can’t enter the cell.

How would phospholipids orient themselves in this situation? Nonpolar Substance Water

For Your Information Plants are covered with a waxy cuticle. Wax is a lipid. Made mostly of Hydrocarbons (C-H) Nonpolar so how does it interact with water? ◦ It doesn’t! That’s why water drips off and doesn’t stick.