chapter 23 lipids created by prof. gary f. porter, ph.d. copyright © 2014 by john wiley & sons,...

Chapter 23LipidsLipids

Created By Prof. Gary F. Porter, Ph.D.

Copyright © 2014 by John Wiley & Sons, Inc. All rights reserved.

Table of Contents

1. Introduction2. Fatty Acids and Triacylglycerols3. Terpenes and Terpenoids4. Steroids5. Prostaglandins6. Phospholipids and Cell Membranes7. Waxes

© 2014 by John Wiley & Sons, Inc. All rights reserved.

1. Introduction


Definition:Lipids are compoundsextracted from livingorganisms using non-polar solvents.

So, lipids include avariety of structuraltypes.

• Fatty Acids– are long chain (>14 carbons) carboxylic acids,– have an even number of carbons,– may be saturated (no double bonds), and – may be unsaturated (contain double bonds).• All double bonds are cis.• Double bonds have weakened intermolecular forces

because of a molecular bend.• They have lower melting points.

2. Fatty Acids


• Triacylglycerol is a triester (a fat or oil)– made of 3 Fatty Acids & Glycerol.– produce monomeric units by hydrolysis.

2. Triacylglycerols


2A. Hydrogenation of Triacylglycerols– Increases M.P.

2. Fatty Acids and Triacylglycerols


2B. Biological Functions of Triacylglycerols include: – long term storage of energy, and – helping us survive starvation conditions.

• Fat and health– Saturated fats are linked to heart disease.– Too much fat in the diet is a health concern.

• Physical properties– Fat is a solid. (saturated)– Oil is a liquid. (unsaturated)



2C. Saponification of Triacylglycerol– Involves the basic hydrolysis of a triacylglycerol.



Detergent • is the anion of a strong

acid.• keeps multivalent metals

solvated.• prevents soap scum.



2F. Reactions of the Carboxyl Group of Fatty Acids



2E. Reactions of the Alkenyl Chain Group of Unsaturated Fatty Acids



The monomeric unit – Is isoprene.– Has 5 carbons.

Larger molecules from isoprene:

3. Terpenes and Terpenoids


See how to find the terpene monomers in the polymers below.



Practice Problem 23.2(a)Show the isoprene units in each of the following terpenes.(b)Classify each as a monoterpene, diterpene, sesquiterpene, and so on.



Carotenes– contain two diterpenes

Vitamin A- is a precursor of a carotene, and- is a diterpene.



3A. Natural Rubber

Vulcanization creates disulfide linkages between chains.



4A. Structure and Systematic Nomenclature

Cyclopentophenanthrenes•α substitution – Group is trans to C-18 methyl•β substitution – Group is cis to C-18 methyl

4. Steroids


4. Steroids


4B. Cholesterol (C27) - Parent compound

Derivatives made from cholesterol:Bile acids (C24)Adrenocortical hormones & progesterone (C21)Male sex hormones (C19)Female sex hormones (C18)

4B. Cholesterol

Dietary Cholesterol •is a mixture of lipids, one of which is cholesterol.•HDL – High Density Lipoproteins

– travel from tissues to liver, and – are an indicator of good health.

•LDL – Low Density Lipoproteins– travel from liver to tissues, and– are an indicator of poor health.

4. Steroids


4C. Sex Hormones•Estrogens – female hormone

•Androgens – male hormone

•Progestins – pregnancy hormone– Suppress ovulation.

4. Steroids


4D. Adrenocortical Hormones– are 28 different Hormones,– are produced in the adrenal cortex located in adrenal glands found on top of the kidneys, and– drive numerous biological regulation activities including the inflammatory response.

4. Steroids


4E. D VitaminsSunlight is needed to produce Vitamin D3. VitaminD3 is needed for health and facilitates the process by which calcium is absorbed to allow proper bone growth.

4. Steroids


• Structure:– Includes twenty carbons. – Has a five membered ring.

• Made from Arachidonic Acid:– Eicosatetraenoic acid

5. Prostaglandins


• Phospholipids are structural components of membranes.

• Phospholipids are most commonly:– Glycerol based or– Sphingosine based.

• Phosphatidic acid is the parent of glycerol based phospholipids.

• Ceramide is the parent of sphingosine based phospholipids.

6. Phospholipids and Cell Membranes


• Phosphatidic acid has three components:– Glycerol,– 2 Fatty Acids, and– Phosphate.Phosphatides have an

additional group bonded to the phosphate.

6. Phospholipids and Cell Membranes h


6A. There are four common phosphatides.

Phosphatidyl: ethanolamine, choline,serine andinositol.





6A. Phosphatide- Is a soap-like

molecule.

6B. Derivatives of Sphingosine (Parent Molecule)– Sphingomyelin

• is a component of myelin found in nerve cell membranes (sheaths).

– Cerebroside• is a brain cell membrane component.



• are esters of long chain fatty acids,• act as a water resistant coat, and• are found on skin, fur, and feathers.

7. Waxes


Ch. 21 - 30

END OF CHAPTER 23

chapter 23 lipids created by prof. gary f. porter, ph.d. copyright © 2014 by john wiley & sons,...

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fatty acids glycerol

carbons carboxylic acids

double bonds

fatty acidsare long

carboxyl group of fatty

number of carbons

monomeric units