What are Lipids n Fat n Triglycerides n Phospholipids n Similar to triglycerides but: n with a Phosphoric acid n Steroids n composed of three fatty acids attached to a cental core of 3 carbon glycerine cental core of 3 carbon glycerine n Solid fat or liquid fat (edible oils) n depends on type of fatty acids included n 30 carbon cyclic compounds l May be attached to fatty acids => Wax

Triglycerides H 2 C-O-CO-CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2- CH 3 H C-O-CO-CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2- CH 3 H 2 C -O-CO-CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CH 2- CH 3

Fatty Acids

Phospholipids Phosphate Glycerine 2 Fatty Acids

Steroids n 30 C compounds

Animals steroids:

Phytosteriods n Steroids from Plants n Inhibit absorption of animal steroids n Phytoestrogen absorbed from Soy and other products can be toxic

Why does the body need Lipids? n Primary store of energy –main sauce of energy for muscles n Protection for organs (cushioning) n Insulation against cold n smooth body shape –women n Body can make most of what it needs from carbohydrates and protein n Needed to supply Essential Fatty Acids n Needed to supply fat soluble vitamins

Essential fatty Acids Structure

Essential Fatty Acids n The body cannot make unsaturated fatty acids with double bonds before the 7th C n We need fatty acids with double bond between carbon 6 and 7 These are called  6 fatty acids They are all poly unsaturated fatty acids having more than just the  6 double bond  3 fatty acids have  6 as well as other double bonds total three or four

Cis and Trans double bonds n Cis double bonds are the only one that occure in natural fatty acids C C C C C C CO 2 H C C C C C C CO 2 H C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C CO 2 H C C C CO 2 H Trans double bond Cis double bond

Transport of Lipids in Blood n Lipids are insoluble in water and blood fluids –must be carried with proteins called Lipoproteins

Lipoproteins n Chylomicra carry fat from Intestine to tissue n LDL ( low density lipoprotein) carry lipids from Liver to tissues carry lipids from Liver to tissues chylomicra return to liver chylomicra return to liver n HDL carry cholesterol from tissues to liver –known as Revers transport

Lipoproteins Chylomicra Intestine Liver Body tissues VLDLP HDLP LDLP IDLP

Danger of Excess Dietary Fat - n Cancer n Undigested fatty acids reaching the colon stimulates cancer n fatty acids make soap that wash of cells off the lining the gut n This acts as a MITOGEN ie stimulates cell growth n Cancer needs two stages to start: Mutagen and then mitagen

Danger of Excess Dietary Fat n Increases cholesterol production –inballance of carbohydrate and fat metabolism –cardiovascular disease n Obesity n Diabetes Cardiovascular Disease