Lipids - Mrs. Sharp's classes

LIPIDS Lipids Made up of C, O, H Types & Functions: 1. Fats & Oils: energy storage & insulation

2. Phospholipids: building blocks of cell membranes 3. Steroids: structure & signaling 1. Fats & Oils (triglycerides) Most familiar a.k.a. neutral fat

Fats animal origin, solid at room temp. Oils plant origin, liquid at room temp. In the body fat functions as: - Insulation against heat loss

- Protective cushion for major organs - Long term energy storage (excess glucose fat) Structure: 1 glycerol + 3 fatty acids

Formation of a triglyceride Nonpolar Neutral molecule

(no charges) What does this mean for how it interacts in water?

All are insoluble in water (immiscible with water) = HYDROPHOBIC Soluble in other non-polar substances

FATTY ACIDS COME IN 2 Types: SATURATED & UNSATURATED SATURATED Fatty Acids Saturated fats have saturated fatty acids All C-C bonds are SINGLE

Solid at room temperature Ex. The animal fats Bacon fat Butter Lard

the more highly saturated the fat, the more energy it provides UNSATURATED Fatty Acids

unsaturated fats have unsaturated fatty acids some of the C-C bonds are DOUBLE liquid at room temperature (kinks formed by dbl bonds prevent close packing)

Ex. Plant Oils Canola oil Safflower oil Olive oil Triglyceride - Unsaturated

Double bonds create kinks in the fatty acid tails fluid consistency 2. Phospholipids

Phosphate G l y c

e r o l Fatty Acid

Fatty Acid 2. Phospholipids similar to triglycerides except that a phosphate group replaces one of the fatty acids thus elements present are = C, H, O, P

Negatively charged polar heads are hydrophilic & soluble in water Nonpolar tails are hydrophobic & turn away from water whenever possible PLs make the backbone of cell membranes

~ polar head faces out / non-polar tails face in ~ Creates the lipid bi-layer we see in cells Magic Milk?

EMULSIFICATION So What? Bile - thats what.

3. Steroids Backbone of 4 fused carbon rings 1. Differ by arrangement of atoms in the rings

2. No fatty acids 3. Different functional groups attached Important Steroids

Cholesterol Estrogen Testosterone

Vitamin D Cholesterol Component of plasma membrane (maintains structure & fluidity)

building block for several steroids (e.g. testosterone & estrogen)