Module 3

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Module 3
2012-10-02 16:20:09
Objective 16 20

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  1. dehydration reaction is usually defined as
    a chemical reaction that involves the loss of a water molecule from the reacting molecule. Dehydration reactions are a subset of elimination reactions. Because the hydroxyl group (–OH) is a poor leaving group, having a Brønsted acid catalyst often helps by protonating the hydroxyl group to give the better leaving group, –OH2+
  2. Three fatty acid chains can be added to a molecule of gycerol to form
  3. The fatty acid chains do not need to be of the same size or saturation
    any combination is possible
  4. Kinky tails =
    more fluid
  5. The formation of triglycerides from three fatty acid chains and a gyceraol molecule is an example of a
    dehydration synthesis; Each fatty acid chain ends in a -COOH. The fatty acid's terminal -OH and a -H on gycerol combine to release water (HOH) and the oxygen bridges the glycerol backbone to the fatty acid "tails"
  6. Phospholipids are formed when
    two fatty tails (carbon and hydrogen only) are joined by a glycerol molecule to a phosphate-containing "head group".
  7. Choline is a common
    part of head groups
  8. Choline, phosphate, gycerol are all group heads that associate with each other and prefer to be around
  9. Phospholipid tails are made up of only
    carbon and hydrogen. Are hydrophobic also.
  10. What is an Amphipathic molecule
    when it has a polar "head" and a non-polar pair of "tails".
  11. Cell membranes are mostly made up of
    lipid bilayers
  12. Orientation of phospholipid molecules
    polar "heads" to inside and outside of cell

    non-polar "tails" sandwiched between
  13. Explain how phospholipids self-assemble into a lipid bilayer
    two separate sheets of polar heads each stay together and associate with water, while their non-polar tails pack in the middle, forming a "sandwich" arrangement.
  14. Name at least 5 types of steroids found in the human body
    • Testosterone (male sex hormone)
    • Cortisol (released in tomes of stress)
    • Estradiol (female sex hormone)
    • Vitaman D (essential for bone growth and repair)
    • Cholesterol (essentail component of the cell membrane)
  15. Steroid hormones are based on the
    cholesterol molecule
  16. Can we live without cholesterol
    No, it is an essential component of the cell membrane.
  17. Cholesteral has a role in regulating the ________ of cell membranes.
  18. Is cholesteral soluble by itself in blood
    Cholesteral is NOT soluble by itself in blood

    in order to reach the cells, it has to be carried by a protein/lipid complex
  19. What type of lipids derive from arachidonic acid and are key chemicals in immune defense and inflammation?
    • Eicosanoids
    • (Prostaglandins and Leukotrienes)
  20. Leukotrienes promote
    an inflammatory response (for example, swelling) when a sensitive person is exposed to an allergen.  By blocking the action of leukotrienes, these inhibitors reduce the inflammatory response.