1. Lipids

2. LIPIDS: Roles in the body
energy storage,
insulation
protection of organs,
steroid hormones,
structural components of cells

3. Health Effects Too many Too few The right/wrong kind
Obesity, heart disease
Too few
Body can’t make important hormones
Dry skin and hair
The right/wrong kind
Too much LDL or trans fats: increased heart disease
More HDL: decrease risk for heart disease

4. Classification Simple Lipids / Triglycerides
Fats and oils: esters of fatty acids and glycerol
Waxes: esters of high molar-mass fatty acids and high molar-mass alcohols
Compound lipids / Phospholipids
yield glycerol, phosphoric acid, fatty acids
Lecithin: common name for phospholipids, isolated from animals (eggs), common non-toxic emulsifying agent used as food additive
Steroids: 17-Carbon structure of 4 fused rings
Misc: fat soluble vitamins (A, D, E, K)

5. Fatty Acids Long carbon chains with carboxylic acid groups
Long carbon chain makes them mostly non-polar (hydrophobic/fatty)
Saturated fats: no double bond, pack together easily, solid at room temp
Unsaturated fats: presence of a double bond
cis or trans
Natural: cis, because of kink, can’t pack together, low dispersion forces, liquid at room temp
Synthetic: trans

6. Mono-unsaturated (MUFA) vs poly-unsaturated (PUFA)
Oleic acid: mono-unsaturated
omega carbon (omega is the last letter of Greek alphabet)
Alpha carbon
linoleic acid: poly-unsaturated
Omega-6 fatty acid
Double bond occurs 6 carbons away from omega carbon =
linolenic acid: poly-unsaturated
Omega-3 fatty acid
Double bond occurs 3 carbons away from omega carbon =

7. Essential fatty acids (EFAs)
Some fatty acids are precursors to important biological molecules, but cannot be synthesized in the body:
Omega-3 and 6 fatty acids are like this.
Omega-3 is important for brain growth and development
reduce inflammation and help prevent risk factors associated with chronic diseases such as heart disease, cancer, and arthritis.
omega-3 fatty acid deficiency include extreme tiredness (fatigue), poor memory, dry skin, heart problems, mood swings or depression, and poor circulation
found in fish, such as salmon, tuna, and halibut, other marine life such as algae and krill, certain plants (including purslane), and nut oils
Omega-6 fatty acids are linked with inflammation and other health problems
Parts taken from University of Maryland Medical Center website (4/16/09)

8. Determining Degree of Saturation
Alkene + Iodine  Addition reaction with color change
Iodine Number: The mass of iodine that is absorbed by 100 g of substance
Number of iodine molecules that add to an unsaturated fat can distinguish between saturated, mono and poly unsaturated fats
Reacts with 1 molecule of iodine
Reacts with 2 molecules of iodine

9. 3.2 g of iodine reacts with 0.01 moles of a fatty acid, how many double bonds does it have?1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

10. Fats and Oils Triglyceride (Triglycerol)
Ester linkages formed from carboxylic acid of fatty acid and alcohol from glycerol
Glycerol: 3 OH groups (hence, triglyceride)
3 R groups usually different
Most have Carbons

11. Fats provide more than 2x the energy that carbs do when oxidized to CO2 and water.
Carbs and Protein: 4 kcal/g
Fats: 9 kcal/g
Carbon atoms in fats are more reduced (not bonded to O) than those of most other food

12. Digestion of Fats Enzyme Catalyzed Hydrolysis Lipase
Opposite of esterification/condensation, requires H2O
Products: 3 fatty acids, and glycerol
Happens in a step-wise fashion (one fatty acid lost at a time)
+ 3 fatty acids
Glycerol

13. Saponification

14. Phospholipids
One of the fatty acid chains on the triglyceride is changed to a phosphate group.
Phosphate like carboxylic acid, COOH,
Makes a phosphate ester

15. Phospholipids polar end (phosphate) Non-polar end (fatty acids)
Forms phospholipid bilayer (liposome / cell membrane)

16. Cell Membrane Fluidity (animation) Semipermeable
Keep bad stuff out, but let good stuff in

17. Steroids Lipids w/ four fused rings
Cholesterol – a steroid with an alcohol
Use in body (on red book cd)
Cholesterol

18. Cholesterol
Progesterone
Estrogen
Testosterone

19. Hormone Uses Sex Hormone Prod-uction Role Other
Androgen (testosterone)
Testes
Development and maintenance of male reproductive system
Estrogen (estradiol)
Ovaries
Same as above for females
Progestin (Progesterone)
Prepare and maintain uterus, help developing embryo

20. HDL vs LDL HDL: high density lipoprotein (45-55% P)
LDL: low density lipoprotein (20-25% P)
Different proportions of protein and lipid
Protein = water soluble, lipid = not
Blood mostly water, LPs needed to transport cholesterol through the body
HDL:
Prevent build up of cholesterol in arteries
can absorb more cholesterol per molecule and can carry it away from arteries,
LDL:
Carry cholesterol to build and repair damaged tissue which accumulates on damaged tissue
LDLs deposit cholesterol in artery walls, causing hardening (plaque) = cardiovascular disease