Chapter 19 Lipids

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Chapter 19Lipids

• CHEM 2124 General Chemistry II
• Alfred State College
• Professor Bensley

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Learning Objectives

• Describe the general characteristics of lipids
• Classify fatty acids and describe the
  relationship between melting point and the number
  of double bonds
• Draw the structure of triacylglycerols and
  describe the difference between a fat and an oil
• Draw the hydrolysis products of triacylglycerols
  (Saponification)

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Lipids

1. Introduction to Lipids

• Lipids are biomolecules that are soluble in
  organic
• solvents and insoluble in water.

• Polarity
• Classification Scheme
• Hydrolyzable Lipids

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Lipids

1. Nonhydrolyzable Lipids

II. Fatty Acids A. General Structure
polar portion hydrophillic
nonpolar portion hydrophobic
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Lipids
B. Saturated vs. Unsaturated Fatty Acids
C. Monounsaturated vs. Polyunsaturated Fatty
Acids

• As the number of double bonds in the fatty acid
• increases, the melting point decreases.

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Lipids
D. Trans fats vs. Cis fats
E. Omega-3 Fatty Acids
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Lipids
III. Triacylglycerols (Triglycerides)

• Triacylglycerols (triglycerides) are three
  esters formed from glycerol and three molecules
  of fatty acids

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Lipids
A. Simple vs. Mixed Triacylglycerols
IV. Fats and Oils
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Lipids
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Lipids
V. Hydrolysis of Triacylglycerols (Soap
Production)

• Soaps are metal salts of fatty acids prepared by
• basic hydrolysis (saponification) of a triacyl-
• glycerol

polar head ionic end
nonpolar tail nonpolar end
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Lipids
O
R
C
CH2O
CH2OH
H2O
R
3
Na -O
CH OH

3 NaOH
CH O
R
3 soap molecules
CH2OH
CH2O
R
glycerol
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