Lipids Fats, Oils, waxes

Lipid Basics Made of C,H,O monomer = glycerol + fatty acids hydrophobic - don’t dissolve in water oil and water don’t mix

Fatty Acids 2 types – saturated and unsaturated - What’s the difference? - saturated fatty acids No double bonds between C atoms - holds the maximum # of H atoms - unsaturated fatty acids contain double bonds between C atoms

Lipids- Fats and Oils Fats & Oils (triglycerides)- long term energy storage Fat has twice the calories of carbohydrates. fat = 9 cal/g sugar= 4 cal/g Health tip: Saturated or hydrogenated fats(bad) vs. unsaturated (good) 2-24

Lipids: types and functions Fats/Oils – long term energy storage, insulation and protection Phospholipids – cell membranes Steroids – make hormones (chemical messengers) Waxes – waterproofing

Saturated fat and fatty acid Fats (Saturated) Solid at room temperature Energy storage in animals contain saturated fatty acids Saturated fat and fatty acid Stearic acid

Body Fat – stores energy, insulates and protects the organs Excess energy is converted to fat Sea mammals rely on fat to keep them warm

Unsaturated fat and fatty acid Oils (Unsaturated) energy storage in plants contain unsaturated fatty acids liquid at room temperature Unsaturated fat and fatty acid Double bond causes molecule to bend Oleic acid

Phospholipids- create the structure of cell membranes only 2 fatty acids (not 3 like fats and oils) 3rd fatty acid is replaced by a phosphate molecule SPONCH

(a) Structural formula (b) Space-filling model Phospholipid structure Phosphate molecule forms a hydrophilic (water loving) head Fatty acid molecules make up a hydrophobic tails CH2 O P CH C Phosphate Glycerol (a) Structural formula (b) Space-filling model Fatty acids (c) Phospholipid symbol Hydrophobic tails Hydrophilic head Hydrophobic tails – Hydrophilic head Choline + Figure 5.13 N(CH3)3 10

myelin - phospholipid that insulates nerve cells We are all literally “Fatheads”

Cholesterol component of cell membrane used to make steroids

Steroids: Lipids that act as Hormones Hormones are chemical messengers - produced in one part of the body, they travel to and cause changes in another part of the body - Hormones control: growth development tissue function sexual function the way our bodies use food, the reaction of our bodies to emergencies, mood - examples estrogens testosterone Estrogen Testosterone

Waxes-Lipids that repel water - found on the surface of leaves - found on animal hair to keep it pliable - found on the feathers of water birds to prevent them from becoming waterlogged