BC Lipid Chemistry and Structure

Lipids Overview

• Triacylglycerols are the principal stored form of energy in the body.

Lipids in Biological Membranes

• Phospholipids are the major structural elements of biological membranes.

Lipid Signaling and Cofactors

• Steroids and eicosanoids are signaling molecules and cofactors.

Fatty Acids

• The general formula for fatty acids is CH₃(CH₂)xCOOH.
• Unsaturated fatty acids have double bonds in their hydrocarbon chains.
• Saturated fatty acids do not have double bonds in their hydrocarbon chains.
• Polyunsaturated fatty acids are most susceptible to lipid peroxidation.
• Saturated fatty acids are solid at room temperature.
• Lipid peroxidation can lead to cell damage, cancer, and atherosclerosis.

Antioxidants and Cholesterol Synthesis

• Vitamin E is a natural antioxidant.
• Cholesterol is synthesized from acetyl-CoA.

Hydrogenation and Lipid Function

• Hydrogenation is the process of adding hydrogen to unsaturated fatty acids.
• Lipids have multiple functions in the body, including energy storage and structural roles.

Prostaglandins and Cell Membranes

• Prostaglandins, thromboxanes, and leukotrienes are eicosanoids.
• Phospholipids and cholesterol are the structural components of cell membranes.
• Amphipathic lipids form a bilayer when mixed with water.
• The fluidity of a membrane is regulated by the ratio of saturated to unsaturated fatty acids.
• The Fluid Mosaic Model describes the structure of cellular membranes.

Fatty Acid Nomenclature

• Monounsaturated fatty acids contain one or more double bonds.
• Palmitic acid is the systematic name for the fatty acid with 16 carbon atoms.
• Unsaturated fatty acids are named based on the location of the first double bond.
• The ω or n-system is used for fatty acid numbering.

Fatty Acid Synthesis

• Arachidonic acid is synthesized from linoleic acid.

Fatty Acid Configuration

• The double bonds in naturally occurring unsaturated fatty acids are in the cis configuration.

Biological Membrane Components

• Proteins are not a structural component of biological membranes.

Sphingolipids and Glycolipids

• Sphingolipids are esters of long chain fatty acids with sphingosine, a long chain amino alcohol.
• Glycolipids contain a monosaccharide as the polar head group.

Pulmonary Surfactant

• Sphingomyelin is a major constituent of pulmonary surfactant and deficiency leads to Respiratory Distress Syndrome.

Sterols

• Cholesterol is a major sterol and a precursor for the synthesis of bile salts, vitamin D, and steroid hormones.

Test your knowledge of common double bonds in monoenoic, dienoic, and trienoic acids! Learn the common and systematic names for various fatty acids and their position of double bonds. Challenge yourself with this quiz and improve your understanding of lipid chemistry.