Lipids *organic molecules with long hydrocarbon chains (nonpolar) *Contain C, H, and O Major functions in the body: (Positive) * energy storage * insulate and protect organs * form cell membranes * hormones

Lipids Negative Effects: Can deposit in the walls of blood vessels and restrict blood flow – atherosclerosis Obesity- Can lead to diabetes or cancer High cholesterol – lead to cardiovascular disease

1. Fats and oils – esters composed of glycerol (1,2,3-propanetriol) and 3 long-chain carboxylic acids (we call them fatty acids). = Triglycerides Type 1: Fats and Oils

Ester Linkage

R 1, R 2, and R 3 (fatty acid – usually all different) - usually a straight chain - usually an even number of carbon atoms - between 14 & 22 carbon atoms - no other functional groups present - differ by number and position of double bonds Saturated FatsUnsaturated Fats All single bonds C-Ccontains C=C tetrahedral (one double = mono, several double = poly) Animal fatsvegetable oils Solids (high mp)Liquids (lower mp) Pack closely togethernot closely packed BAD

The body can synthesize required fatty acids except for 2. –Omega-6 linoleic –Omega-3 linolenic Given in data book –These two acids are called essential fatty acids b/c you must obtain them from your diet –Obtained from plants and fish – shellfish, leafy veggies, canola oil

Unsaturated fatty acids undergo addition reactions (organic) Iodine Number – I 2 reacts with double bonds. I 2 is added to a fat – the more I 2 reacts, the more double bonds present (more unsaturated) Degree of Unsaturation Textbook – the number of grams of iodine which reacts with 100 g of fat.

Calculating Iodine # Iodine (g) X 100 (g) / acid (g)

Calculating Iodine # 2 double bonds in the acid – look at data book 2 moles of I 2 needed to react with 1 mole of acid Mass of linoleic acid = 280 g/mol Mass of I 2 = 254 g/mol 280 g of acid react with 508 g of I x 100/280 =181g Iodine # = 181

Fats in the Food Industry Hydrogenated Fat – oils which have been modified by adding hydrogen to decrease the degree of unsaturation. Why? More convenient for packing/storing – it’s a solid. Problem- double bonds go from cis to trans in the process – This results in trans fats. Very common in processed foods. Raises LDL and lowers HDL

Digestion of Fats Fats and oils are insoluble and can’t be transported in the blood. They must be broken down in the gut with the help of an enzyme called “lipase” through hydrolysis reactions. Takes a long time to break down.

Other Lipids What are phospholipids? What are steroids? Draw a generic structure of a triglyceride, a phospholipid (lechtin), and a steroid (cholesterol). What is cholesterol? What is HDL and LDL cholesterol and why are they important.