Organic compounds 2of4 (Lipids)

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Organic compounds 2of4 (Lipids)
2013-12-14 21:49:31
Organic compounds 2of4 Lipids
Organic compounds 2of4 (Lipids)
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  1. What is a lipid?
    • Organic compound composed of C, H, and O, but do not have a 2H:1C:1o ratio like carbohydrates.
    • Lipids usually have less electronegative O atoms, which makes then less polar (less polar covalent bonds). HYDROPHOBIC.
    • Most lipids are insoluble in polar solvents (like water) due to less polar covalent bonds.
  2. What % of body mass do lipids make up in the average adult?
  3. How do lipids become more soluble in blood plasma?
    • Due to being hydrophobic, only the smallest lipids (some fatty acids) dissolve in water.
    • Lipids join with proteins for form lipoproteins.
    • Lipoproteins are soluble because the proteins are on the outside and the lipids are on the inside.
  4. What are the types of lipids?
    • Fatty acids
    • Triglycerides (fats and oils)
    • Phospholipids (lipids that contain phosphorus)
    • Steroids (lipids that contain rings of carbon atoms)
    • Eicosanoids (20-carbon lipids
    • Variety of other lipids, including fat-soluble vitamins (vitamins A, D, E, and K) and lipoproteins
  5. What are fatty acids?
    • Made of a carboxyl group (-COOH) and a hydrocarbon chain.
    • Used to synthesize triglycerides and phospholipids.
    • One of the simplest lipids.
    • Can be saturated, or unsaturated.
  6. What are saturated fatty acids
    • Saturated refers to the carbons, of the hydrocarbon chains, saturated with hydrogen, so no double bonds between carbons. (their valence shells are full due to non-polar covalent bonds with H)
    • No kinks or bends in hydrocarbon chain.
  7. What are unsaturated fatty acids?
    • Unsaturated refers to ONE OR MORE double bonds between the carbons in the hydrocarbon chains. This means the carbons are UNsaturated with hydrogen. (valence shells not full due to non-polar covalent bonds with hydrogen)
    • Bends or kinks occur in the hydrocarbon chain at the site of double bonds between carbons. (where there would have been two hydrogens)
  8. Whats the difference between monounsaturated and polyunsaturated fatty acids?
    • Monounsaturated refers to ONE double bond between carbons in the carbon skeleton. (1 bend or kink)
    • Polyunsaturated refers to TWO OR MORE double bonds between carbons in the carbon skeleton. (2 or more bends or kinks)
  9. What are triglycerides? How are they made?
    • Consists of ONE 3-carbon glycerol molecule and THREE fatty acids.
    • Can be liquid (oil) or a solid (fat) at room temp depending on fatty acid composition (saturated or unsaturated).
    • Each fatty acid bonds to a carbon in the glycerol molecule (ester linkage) through dehydration synthesis
    • Hydrolysis breaks down a single molecule of a triglyceride into three fatty acids and glycerol.
  10. How are triglycerides used by our body?
    • Triglycerides are the most concentrated form of chemical energy in the body.
    • Provide more than twice as much energy as carbohydrates and proteins.
    • Bodies can store unlimited amounts of triglycerides in adipose (fat) tissue.
  11. What is a fat?
    • A triglyceride that is solid at room temp.
    • Fats contain mostly saturated fatty acids (no bends or kinks) so they can pack closely together to form solids.
  12. What is a saturated fat?
    • A fat that consists of mostly saturated fatty acids.
    • Occur mostly in meats and non-skim dairy products, but few in plants.
    • Diets that contain large amounts of saturated fats are associated with disorders such as heart disease and colorectal cancer.
  13. What is an oil?
    • A triglyceride that is liquid at room temp.
    • Oils consist of mostly unsaturated fatty acids.
    • Does not pack together and solidify at room temp due to kinks or bends in fatty acids.
  14. What is a monounsaturated fat?
    • A fat or oil whose triglycerides consist of mostly monounsaturated (1 kink or bend) fatty acids
    • Both monounsaturated and polyunsaturated fats are believed to decrease the risk of heart disease.
  15. What is a polyunsaturated fat
    • A fat or oil whose triglycerides consist of mostly polyunsaturated (2 or more kinks or bends)
    • Both monounsaturated and polyunsaturated fats are believed to decrease the risk of heart disease.
  16. Why do people get fat?
    Excess dietary carbohydrates, proteins, fats, and oils are all deposited in adipose tissue AS TRIGLYCERIDES.
  17. What are phospholipids?
    • A polar head attached to two non-polar fatty acids. (amphipathic)
    • The polar head is a 3 carbon glycerol molecule that has two of its carbons attached to fatty acids, but the third is attached to a phosphate group (-PO4^3-) that attaches to a small polar molecule that usually contains N.
    • The head is polar and forms hydrogen bonds with water, that tails are non-polar and only interact with lipids.
  18. What does amphipathic refer to?
    • amphi- = on both sides, -pathic = feeling
    • Molecules that have polar and non-polar parts (phospholipids)
  19. What are phospholipids used for?
    • Phospholipids form ALL cell membranes.
    • Amphipathic phospholipids line up tail-to-tail in a double row. 
    • The polar heads form hydrogen bonds with water (hydrophilic), and the non-polar tails (hydrophobic) interact with each other. This lines up the tails end to end, leaving the heads on the outside, and tails enclosed inside. 
    • This membrane forms the shell of a sphere.
    • 0 0 0 0 0 0
    • ll ll ll  ll ll ll
    • ll ll ll  ll ll ll
    • 0 0 0 0 0 0
  20. What are steroids?
    • Lipid molecules with 4 carbon rings (colored gold in models)
    • Common steroids in the body are cholesterol, vitamin D, estrogen, testosterone, cortisol, and bile salts (sterols)
    • Body cells synthesize other steroids from cholesterol (a steroid)
  21. What are sterols?
    • The common steroids (a lipid) of the body that have at least one hydroxyl (alcohol) group (-OH) that makes them slightly amphipathic.
    • Include: cholesterol, testosterone, estrogen, cortisol, bile salts, vitamin D 
    • Slightly amphipathic due to at least 1 hydroxyl group (-OH) and a non-polar portion consisting of 4 carbon rings (multiple rings, not 4C) and their functional groups.
  22. What are the sterols and their uses?
    • Cholesterol- Needed for cell membrane structure
    • Cortisol- Needed to maintain blood sugar levels
    • Vitamin D- Related to bone growth
    • Bile salts- Needed for lipid digestion and absorption 
    • testosterone- Required for regulating sexual functions
    • estrogen- Required for regulating sexual functions
  23. What are eicosanoids?
    • eicosan- = twenty
    • 20 carbon fatty acid chains derived from oxidation.
    • Immune system modulators.
    • Lipids derived from a 20 carbon fatty acid called ARACHIDONIC ACID.
    • Two principal subclasses are PROSTAGLANDINS and LEUKOTRIENES.
  24. What are the functions of prostaglandins? (An eicosanoid)
    • Wide variety of functions:
    • Modify responses to hormones
    • Participate in inflammatory responses 
    • Prevent stomach ulcers
    • Dilate (enlarge) air ways of the lungs
    • Regulate body temp
    • Influence formation of blood clots
  25. What are the functions of leukotrienes? (An eicosanoid)
    Participate in allergic and inflammatory responses