Organic compounds - Lipids
- Lipids are hydrophobic.
- Mostly hydrocarbons with nonpolar bonds.
- Three families: fats, phospholipid, steroids.
- Large molecules composed of glycerol and 3 fatty acids.
- Glycerol : C3H8O3 alcohol
- carboxyl head -COOH
- long non-polar hydrocarbon tail : insoluble in H2O.
- water H-bonds to each other but not fats.
- if no double bonds then a straight saturated fat (lots of H).
- straight tails pack well : solid fat.
- if there are double bonds then the tail is bent (unsaturated).
- bent tails don't pack well : liquid fat.
- Bonus: bond a metal hydroxide with a fatty acid : soap!
- nonpolar tails mix with nonpolar grease.
- polar heads mix with water...
- shake : little clumps of grease surrounded by soap molecules.
- Li soaps are used as lubricants.
- Na soaps are solid
- K soaps are liquid.
- Molecules composed of glycerol, 2 fatty acids and phosphate group.
- Fatty acid end hydrophobic, phosphate end hydrophilic.
- Tends to form a double layer (bilayer) - tail to tail with PO4 heads out.
- Forms a membrane !
- Large molecules composed of alcohol and 3 fatty acids.
- Has no fatty acids.
- Four carbon rings with various functional groups attached.
- Examples: cholesterol, some hormones (sex).