Lipids

the reaction of corn oil and hydrogen (H2) with a nickel catalyst

Hydrogenation

CH3-(CH2)12-COOH

Mystic acid

CH3-(CH2)7-CH=CH-(CH2)7-COOH

Oleic acid

CH3−(CH2)14−COOH

Palmitic acid

CH3−(CH2)5−CH=CH (CH2)7−COOH

Palmitoleic acid

Name the Monounsaturated fatty acids

Palmitoleic acid Oleic acid

Name all the unsaturated fats

Palmitoleic acid Oleic acid Linoleic acid Linolenic acid Arachidonic acid

A polyunsaturated fatty acid contains more than one

carbon-carbon double bond

Lipids are compounds that are soluble in

chloroform or ether

T or F Vegetable oils have higher melting points than fats

false

A triacylglycerol that is solid at room temperature is called a(n)

fat

Name all the lipids

fats (saturated fatty acids) oils (unsaturated fatty acids) glycerophospholipids triacylglycerols waxes steroids cholesterol

The products of the acid catalyzed hydrolysis of a fat are

fatty acids and glycerol

What are the products of saponification?

glycerol salts of fatty acids

What are the products of hydrolysis reaction in lipids?

glycerol and three fatty acids

the reaction of glyceryl trilinoleate from safflower oil with water and HCl

hydrolysis

the reaction of glyceryl tristearate with water in the presence of lipase enzyme

hydrolysis

Which of the following compounds is a glycerophospholipid?

lecithin

Name the omega 3 fatty acids.

linolenic acid

Compared to saturated fatty acids, unsaturated fatty acids have

lower melting points

The name of the reaction that occurs when a fat reacts with sodium hydroxide and water is

saponification

the reaction of palm oil with KOH

saponification

What is the product of hydrogenation reaction in lipids?

saturated fat (single bonds)

Which fatty acid are usually solids at room temperature?

saturated fatty acids

Cholesterol belongs to the ________ group of lipids.

steroids

Unsaturated fatty acids have lower melting points than saturated fatty acids because

the cis double bonds give them an irregular shape

T or F Hydrogenation of oils coverts some cis double bonds to trans double bonds

true

T or F There are more unsaturated fats in vegetable oils

true

Which of the following lipids will give a single molecule of fatty acid when hydrolyzed?

wax

CH3-(CH2)3-(CH2-CH=CH)4-(CH2)3-COOH

Arachidonic acid

Why does stearic acid melt at 69 ∘C but linoleic acid melts at −5∘C?

Because the molecules of A SATURATED FATTY ACID (like STEARIC ACID) fit closer together than the molecules of A POLYUNSATURATED FATTY ACID (like LINOLEIC ACID), there are STRONGER attractions between saturated fatty acid molecules, requiring MORE energy (HIGHER melting points) to break them apart and form liquid.

Lauric Acid

12 carbon saturated fatty acid no double bond

Mystic Acid

14 C saturated fatty acid no double bond

Palmitic acid

16 C Saturated fatty acid no double bond

Palmitoleic acid

16 C monounsaturated fatty acid 1 double bond starting at Carbon 9

Oleic acid

18 C monounsaturated fatty acid one double bond starting at Carbon 9

linoleic acid

18 C polyunsaturated fatty acid 2 double bonds at Carbon 9, 12

linolenic acid

18 C polyunsaturated fatty acid 3 double bonds on Carbon 9, 12, 15

stearic acid

18 C saturated fatty acid no double bonds

Describe some similarities and differences in the structures of a saturated fatty acid and an unsaturated fatty acid.

All fatty acids contain a LONG chain of carbon atoms with a CARBOXYLIC ACID GROUP. Saturated fatty acids contain ONLY CARBON-CARBON SINGLE BONDS; unsaturated fatty acids contain ONE OR MORE DOUBLE BONDS.

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?

In a CIS fatty acid, the hydrogen atoms are ON THE SAME SIDE of the double bond, which produces a kink in the carbon chain. In a TRANS fatty acid, the hydrogen atoms are ON OPPOSITE SIDES of the double bond, which gives a carbon chain without any kink.

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

In unsaturated fatty acids, the cis double bonds cause the carbon chain to bend or "kink", which gives the molecules an irregular shape. As a result, unsaturated fatty acids cannot stack as closely as saturated fatty acids and thus have fewer dispersion forces between their carbon chains.

CH3-(CH2)10-COOH

Lauric acid

Name all the saturated fatty acid

Lauric acid Mystic acid Palmitic acid Stearic acid

CH3-(CH2)4-CH=CH-CH2-CH=CH-(CH2)7-COOH

Linoleic acid

CH3−(CH2)4−CH=CH−CH2−CH=CH−(CH2)7−COOH

Linoleic acid

Name the Omega-6 fatty acids

Linoleic acid Arachidonic acid

CH3-(CH2)16-COOH

Stearic acid

T or F Animal fats have more saturated fats

True

Waxes are lipids derived from

a long-chain alcohol and a long-chain fatty acid

arachidonic

20 C polyunsaturated fatty acid 4 double bonds on Carbon 5, 8, 11, 14

arachidic acid

20 C saturated fatty acid

Name the polyunsaturated fatty acid

Linoleic acid Linolenic acid Arachidonic acid

CH3-CH2-CH=CH-CH2-CH=CH-CH2-CH=CH-(CH2)7-COOH

Linolenic acid

Commercially, liquid vegetable oils are converted to solid fats such as margarine by

hydrogenation