Chapter 5- The Lipids: Triglycerides, Phospholipids, and Sterols

Question 1

Fats include

Answer 1

triglycerides (fats and oils), phospholipids, and sterols.

Question 2

Triglycerides are

Answer 2

glycerol backbones and three fatty acids attached.

Question 3

Fatty acids vary in

Answer 3

carbon chain lengths, degree of unsaturation, and number of double bonds.

Question 4

Saturation affects the

Answer 4

physical characteristics of the fat and its storage properties.

Question 5

Trans-fatty acids

Answer 5

which are altered, have the same negative health effects as saturated fatty acids.

Question 6

Structure of FA

Answer 6

Methyl CH3

Acid COOH

Question 7

The Length of the Carbon Chain

Answer 7

Long-chain fatty acids are found primarily in meat, fish, and vegetable oils.
Medium- and short-chain fatty acids are found in dairy products.

Question 8

The Degree of Unsaturation

Answer 8

Saturated fatty acids carry the maximum possible number of hydrogen atoms.
When most of the fatty acids are saturated it is called a saturated fat.

Question 9

Unsaturated fatty acid

Answer 9

hydrogen atoms and have at least one double bond.

Question 10

The double bond is considered

Answer 10

the point of unsaturation.

Question 11

Monounsaturated fatty acids lack

Answer 11

two hydrogen atoms and have one double bond.

Question 12

When most of the fatty acids are monounsaturated

Answer 12

it is called a monounsaturated fat.

Question 13

Polyunsaturated fatty acids (PUFA)

Answer 13

lack four or more hydrogen atoms and have at least two or more double bonds.

Question 14

When most of the fatty acids are polyunsaturated

Answer 14

it is called a polyunsaturated fat.

Question 15

Linolenic acid is an essential fatty acid.

Answer 15

Omega 3

has the location of the double bond in the third position.

Question 16

Linoleic acid is an essential fatty acid.

Answer 16

omega-6 fatty acid has the location of the double bond in the sixth position.

Question 17

Omega Number

Answer 17

refers to the position of the first double bond.

Question 18

Triglycerides

Answer 18

lipids with three fatty acids attached to a glycerol.

Question 19

Firmness

Answer 19

Saturated fats are solid at room temperature.
Polyunsaturated fats are liquid at room temperature.
Shorter fatty acid chains are softer at room temperature than longer chains.

Question 20

Stability

Answer 20

Saturated fat is more resistant to oxidation.
Monounsaturated fat is slightly less susceptible to spoilage.
Polyunsaturated fat spoils most readily.

Question 21

Protection from rancidity

Answer 21

Sealed in airtight containers away from light
Add antioxidants
Hydrogenation

Question 22

Hydrogenation

Answer 22

Protects against oxidation therefore prolonging shelf life

Alters texture

Question 23

Trans-Fatty Acids

Answer 23

Changed from cis to trans configuration and act like saturated fats in the body
Heart disease connection is being researched.
Conjugated linoleic acid is a naturally occurring trans fat that may be beneficial to health.

Question 24

Phospholipids and sterols

Answer 24

have unique chemical structures that allow them to have unique roles in the body.

Question 25

Sterols have

Answer 25

multiple-ring structure.

Question 26

Phospholipids in Foods

Answer 26

Phospholipids contain glycerol, two fatty acids and a phosphate group with a molecule of choline.
Used as emulsifiers in food industry
A well-known phospholipid is lecithin.
Food sources of lecithin include eggs, liver, soybeans, wheat germ and peanuts.

Question 27

Roles of Phospholipids

Answer 27

Enable transport of lipids across cell membranes
Emulsifiers
Lechithin is made by the liver.

Question 28

Sterols

Answer 28

A well-known sterol is cholesterol

Question 29

Sterols in Foods

Answer 29

Found in plant and animal foods

Cholesterol is found in animal foods only—meat, eggs, fish, poultry and dairy products (exogenous).

Question 30

Roles of Sterols

Answer 30

Starting material for bile acids, sex hormones, adrenal hormones and vitamin D
Structural component of cell membranes
Liver produces 800-1500 mg cholesterol per day (endogenous).
Atherosclerosis is a disease that causes heart attacks. It occurs when cholesterol forms deposits in the artery wall.

Question 31

Lipids tend to separate from the watery fluids of digestion.

Answer 31

This is due to the hydrophobic nature of lipids.

Question 32

Digestive enzymes are

Answer 32

hydrophilic, or water loving.

Question 33

Bile from the liver

Answer 33

emulsifies lipids.

Question 34

Enzymes

Answer 34

then able to break down lipids to monoglycerides and fatty acids.

Question 35

Lipid Digestion

Answer 35

In the mouth, the salivary glands release lingual lipase.

Muscle contractions in the stomach disperse fat into smaller droplets. Fat is exposed to gastric lipase enzyme.

Question 36

In the Small Intestine

Answer 36

Bile is released.
Pancreatic and intestinal enzymes hydrolyze lipids to monoglycerides and fatty acids.
Phospholipids are hydrolyzed.
Sterols are absorbed as is.

Question 37

unlimited amounts of fat

Answer 37

Can be stored by body in excess

Question 38

The liver can also convert excess carbohydrate and protein

Answer 38

to fat

Question 39

Fat needs what to breakdown?

Answer 39

Carbs

Question 40

Roles of Triglycerides

Answer 40

Energy reserve when stored
Use carbohydrate and protein efficiently
Insulation
Shock protection

Question 41

Linoleic Acid and the Omega-6 Family

Answer 41

Supplied by vegetable oils and meats

Question 42

Linolenic Acid and the Omega-3 Family

Answer 42

Must be supplied by food

Important for eyes, brain and heart

Question 43

Essential FA

Answer 43

cannot be made by the body.
Linoleic Acid and the Omega-6 Family
Linolenic Acid and the Omega-3 Family

Question 44

High intakes of saturated fat and trans fat and high blood LDL cholesterol

Answer 44

related to increased risk for heart disease.

Question 45

Omega-3 fatty acids in the diet

Answer 45

appear to have a protective effect.