The most important lipids are fats and oils, which store energy;
these lipids are made from glycerol plus fatty acids.
IMPORTANT BUILDING BLOCKS:
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Fatty acids: –COOH at the end of a long hydrocarbon chain. _ _ Saturated fatty acids contain single bonds only. _ _ Unsaturated fatty acids contain at least one double bond. Other building blocks:
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 glycerol
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 isoprene | |
FATS AND OILS:
- Monoglycerides and diglycerides: glycerol + 1 or 2 fatty acids.
- Triglycerides or fats: glycerol + 3 fatty acids
- Those liquid at room temperature are commonly called oils.
- For each fatty acid added to glycerol, one molecule of water splits out (dehydration).
- Fat digestion adds water molecules to split fatty acids from glucose.
- Fats have more calories per gram than most other compounds.
- Those liquid at room temperature are commonly called oils.
- Phospholipids (like phosphatidyl choline): occur mostly in membranes.
- Sphingolipids (like spingomyelin): have sphingosine instead of glycerol.
- Glycolipids (like cerebrosides and gangliosides in the brain): have sugar instead of glycerol.
- Waxes are long-chain alcohols found in plants.
- Terpenes are odorous hydrocarbons in plants, composed of isoprene units.
- Carotenoids (carotenes and xanthophylls) are plant pigments composed of isoprene units.
- Steroids include cholesterol and its derivatives.