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1
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- Lipids make up the most structurally heterogeneous class of
macromolecules, but all share the the property of being wholly or partly
insoluble in water
- Fats are high energy, compact storage molecules also known as triacylglycerols
or triglycerides. They are constructed by joining a glycerol molecule to
three fatty acids.
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|
2
|
|
|
3
|
|
|
4
|
|
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5
|
- Fatty acids consist of a carboxyl group and a hydrophobic hydrocarbon
tail. The carboxyl group takes part in an ester linkage with the
glycerol.
- Saturated fatty acids have the maximum number of hydrogen atoms because
of single bonding between all the carbons. Unsaturated fatty acids
(present in oils) have one or more double bonds between the carbons,
causing kinks in the molecule and reducing the number of bonding sights
for hydrogen atoms.
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6
|
- Phospholipids substitute the third fatty acid of a triacylglycerols with
a negatively charged phosphate group, which may be joined, in turn, to
another small molecule. Such bonding introduces polarity and hence water
solubility to one end of the molecule, making phospholipids ideally
suited for construction of cell membranes.
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7
|
- Steroids, such as cholesterol and the sex hormones, have a carbon
skeleton composed of four fused rings, with variation in the number and
type of functional groups or atoms attached.
|
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8
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|
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9
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|
|
10
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Notes
