23. Lipids

For each of the following fatty acids, give the shorthand notation for the number of carbon atoms and double bonds, and classify as saturated, monounsaturated, or polyunsaturated:

a. linoleic acid

How does the structure of a fatty acid with a cis double bond differ from the structure of a fatty acid with a trans double bond?

How does the double bond influence the dispersion forces that can form between the hydrocarbon chains of fatty acids?

Compare the structures and functional groups of arachidonic acid and prostaglandin PGE₁.

What are some effects of prostaglandins in the body?

How does an anti-inflammatory drug reduce inflammation?

Sunflower seed oil can be used to make margarine. A triacylglycerol in sunflower seed oil contains two linoleic acids and one oleic acid.

b. Using one of the isomers, write the reaction that takes place when sunflower seed oil is used to make solid margarine.

Draw the skeletal structure and give the name and omega number of the following fatty acid:

CH₃CH₂CH₂CH₂CH₂HC=CHCH₂HC=CHCH₂CH₂CH₂CH₂CH₂CH₂CH₂COOH

Certain omega-3 fatty acids can be found only in animal sources, such as fatty fish. Two of these are eicosapentaenoic acid (EPA) [20:5] and docosahexaenoic acid (DHA) [22:6], both of which are ω-3 fatty acids. DHA has been shown to be important in healthy brain development, so it has recently been added to infant formulas. Breast milk is rich in DHA as long as the mother maintains a healthy diet that includes fish. Draw skeletal structures of the fatty acids EPA and DHA.

The most prevalent fatty acid in coconut oil is lauric acid, a saturated fatty acid containing 12 carbons. Draw lauric acid in skeletal structure.

Draw the condensed structural formula and skeletal structure of the saturated fatty acid with 16 carbon atoms. What is the name of this fatty acid?