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CHAPTER 29

Lipid Synthesis: Storage Lipids, Phospholipids, and Cholesterol

Page 523

29.1 Phosphatidate Is a Precursor of Storage Lipids and Many Membrane Lipids
29.2 Cholesterol Is Synthesized from Acetyl Coenzyme A in Three Stages
29.3 The Regulation of Cholesterol Synthesis Takes Place at Several Levels
29.4 Lipoproteins Transport Cholesterol and Triacylglycerols Throughout the Organism
29.5 Cholesterol Is the Precursor of Steroid Hormones

Fats are converted into triacylglycerol molecules, which are widely used to store excess energy for later use and to fulfill other purposes, illustrated by the insulating blubber of whales. The natural tendency of fats to exist in nearly water-free forms makes these molecules well suited to these roles.

We now turn from the metabolism of fatty acids to the metabolism of lipids, which are built from fatty acids or their breakdown products. We will consider three classes of lipids: triacylglycerols, which are the storage form of fatty acids, membrane lipids, which are made up of phospholipids and sphingolipids, and cholesterol, a membrane component and a precursor to the steroid hormones.