3. Lipids as Signals, Cofactors, and Pigments

Phosphatidylinositols and Sphingosine Derivatives Act as Intracellular Signals

Eicosanoids Carry Messages to Nearby Cells

Steroid Hormones Carry Messages between Tissues

Vascular Plants Produce Thousands of Volatile Signals

Vitamins A and D Are Hormone Precursors

Vitamins E and K and the Lipid Quinones Are Oxidation-Reduction Cofactors

Dolichols Activate Sugar Precursors for Biosynthesis

Many Natural Pigments Are Lipidic Conjugated Dienes

Polyketides Are Natural Products with Potent Biological Activities