Chapter 5b: The Structure and Function of Macromolecules Lipids

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Chapter 5bThe Structure andFunction
ofMacromolecules(Lipids)
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Polymers, Monomers, and Lipids
Lipids posses numerous C-H bonds (i.e., they are
very hydrocarbon-like)

• Lipid monomers are less persistent than the above
  monomers
• Consequently, lipids are less-readily described
  using the same polymeric terms (other than
  triacylglycerides, well ignore lipid synthesis)

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Various Lipids
Fat
Steroid hormone
Fatty acid
Sex hormone
Palmitic acid
Testosterone
Triacylglycerol
Estrogen
Lipids do not share a common core structure
Triglyceride
Waxes
Saturated fatty acid
Lard
Unsaturated fatty acid
Omega-3-fatty acids
Monounsaturated fatty acid
Free fatty acids
Trans fatty acid
Butter
What is common to lipids is their hydrophobicity
Polyunsaturated fatty acid
Margarine
Stearic acid
Olive oil
Oleic acid
Flax seed oil
Oil
Toasted Sesame oil
Phospholipid
Bile salts
Phosphatidylcholine
Vegetable shortening
Steroid
Hydrogenated vegetable shortening
Cholesterol
Partially hydrogenated veg. short.
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Fat Molecule Triacyl Glycerol
Energy
ester linkage
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Saturated Unsaturated F.A.
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Fatty AcidsSaturated, Unsaturated
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Fatty AcidsCis, Trans, Saturated
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Triacylglycerols, -ides
Fats possess more energy per molecule and less
hydration compared with carbohydrates, resulting
in fats possessing much more energy stored per
unit mass or volume
Saturated
Unsaturated
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Fat Functions
In animals such as ourselves, fats are stored in
adipose cells
Fats are also important as cushions for body
organs and as an insulating layer beneath skin
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Fat versus Oil
Fats function in biological systems as energy
storage molecules, particular for organisms or
stages of life cycles in which mobility and
energy storage are simultaneously necessary,
e.g., nuts, seeds, and animals

• Fat
• Fully saturated
• Solid at room temp.
• gt high-temp. stability

• Oil
• Unsaturated
• Liquid at room temp.
• gt low-temp. fluidity

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Fatty Acid Melting Points
Know the trends in this figure, not the specific
numbers
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Olive Oil, Blackout of 05
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Phospholipids
Polar group
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Phospholipid Bilayer
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Micelles
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Biological Membranes
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Cholesterol
You should be able to recognize this as a Steroid
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Cholesterol
Cholesterol is a membrane temperature fluidity
buffer
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Steroids
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The End