Biochemistry of Cells

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Lipids are hydrophobic –”water fearing”

Includes fats, waxes, steroids, & oils

Do NOT mix with water

FAT MOLECULE

Slide 38

Function of Lipids

Fats store energy, help to insulate the body, and cushion and protect organs

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Types of Fatty Acids

Unsaturated fatty acids have less than the maximum number of hydrogens bonded to the carbons (a double bond between carbons)

Saturated fatty acids have the maximum number of hydrogens bonded to the carbons (all single bonds between carbons)

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Types of Fatty Acids

Single Bonds in Carbon chain

Double bond in carbon chain

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Triglyceride

Monomer of lipids

Composed of Glycerol & 3 fatty acid chains

Glycerol forms the “backbone” of the fat

Organic Alcohol (-OL ending)

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Triglyceride

Glycerol

Fatty Acid Chains

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Fats in Organisms

Most animal fats have a high proportion of saturated fatty acids & exist as solids at room temperature (butter, margarine, shortening)

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Fats in Organisms

Most plant oils tend to be low in saturated fatty acids & exist as liquids at room temperature (oils)

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Fats

Dietary fat consists largely of the molecule triglyceride composed of glycerol and three fatty acid chains

Glycerol

Fatty Acid Chain

Condensation links the fatty acids to Glycerol

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Lipids & Cell Membranes

Cell membranes are made of lipids called phospholipids

Phospholipids have a head that is polar & attract water (hydrophilic)

Phospholipids also have 2 tails that are nonpolar and do not attract water (hydrophobic)

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Steroids

The carbon skeleton of steroids is bent to form 4 fused rings

Cholesterol is the “base steroid” from which your body produces other steroids

Estrogen & testosterone are also steroids

Cholesterol

Testosterone

Estrogen

Slide 48

Synthetic Anabolic Steroids