Lipids

LipidsLipids hydrophobic molecules with C, H, and Oreserve energy source 1 gram of lipid contains 2.25x as much energy 1 gram of lipid contains 2.25x as much energy as 1 gram of Carbohydrateas 1 gram of Carbohydrate insulation of body, protect internal organsinsulation of body, protect internal organs main structural component of cell membranesmain structural component of cell membranes found in steroids and hormones that regulate found in steroids and hormones that regulate and maintain body systemsand maintain body systems4 types of Lipids

1.1. FATSFATS

►made of fatty acid(s) attached to made of fatty acid(s) attached to glycerol moleculeglycerol molecule

►Triglycerides are most commonTriglycerides are most common 3 fatty acids attached to glycerol3 fatty acids attached to glycerol held together by ester held together by ester

linkagelinkage

Fatty Acids:Fatty Acids:► long carbohydrate chain with carboxyl gp long carbohydrate chain with carboxyl gp

(COOH) on end(COOH) on end► can be saturated (no double bonds)can be saturated (no double bonds)► or unsaturated (has at least one double bond)or unsaturated (has at least one double bond)► saturation affects physical properties of the saturation affects physical properties of the

fatfat

Saturated Fats:Saturated Fats:►solid at room temp. due to van der solid at room temp. due to van der

Waal’s forces in long carbon chainWaal’s forces in long carbon chain

Unsaturated Fats:Unsaturated Fats:►usually oils (liquid at room temp.)usually oils (liquid at room temp.)

►see pg 36see pg 36

2.2. PHOSPHOLIPIDSPHOSPHOLIPIDS

►molecules that make up the cell molecules that make up the cell membranemembrane

►glycerol/phosphate hydrophillic headglycerol/phosphate hydrophillic head►2 fatty acids hydrophobic tails2 fatty acids hydrophobic tails

►phospholipids arrange themselves into phospholipids arrange themselves into different structures:different structures:

• cell membrane’s lipid bilayer exposed exposed to cytoplasm and extracellular fluid (water based) inside and outside of cell but prevents dissolved substances from crossing membrane

•

3. STEROIDS3. STEROIDS► lipids often found in cell membrane (ex lipids often found in cell membrane (ex

cholesterol)cholesterol)

►consist of 4 fused hydrocarbon rings consist of 4 fused hydrocarbon rings and several different functional groupsand several different functional groups

►cholesterol can be converted in body cholesterol can be converted in body to vitamin D and bile salts (used to to vitamin D and bile salts (used to digest fats)digest fats)

►estrogen, testosterone, and estrogen, testosterone, and progesterone are steroid sex progesterone are steroid sex hormoneshormones

4. WAXES4. WAXES

► lipids with long fatty acid chains linked lipids with long fatty acid chains linked to alcohols or carbon ringsto alcohols or carbon rings

►found as waxy coating on leaves, fruit, found as waxy coating on leaves, fruit, etcetc