Chapter 5: Lipids

Question 1

Lipids (5)

Answer 1

• triglycerides
• phospholipids
• sterols
• carbon, oxygen, and hydrogen
• hydrophobic

Question 2

Functions of lipids (6)

Answer 2

• store and provide energy
• insulation
• manufacture steroids and bile
• transport fat-soluble nutrients in blood
• manufacture sex hormones
• structure of cell membranes

Question 3

Fatty acids (2)

Answer 3

• triglycerides and phospholipids

- chain of carbon and hydrogen atoms with a carboxyl group at alpha end and metal group at omega end

Question 4

Fat

Answer 4

• more kcal than carbs and proteins because of higher ratio of carbon and hydrogen to oxygen
• 9 kcal/g

Question 5

Fatty acids vary in..(3)

Answer 5

• length of carbon chain
• degree of saturation
• shape

Question 6

Length of fatty acids (3)

Answer 6

carbon length of fatty pics 2 to 80 carbons long

• most common 12 to 24 carbons
• short chain, medium chain, long chain

Question 7

Short-chain fatty acids

Answer 7

2 to 4 carbons

Question 8

Medium-chain fatty acids

Answer 8

6 to 10 carbons

Question 9

Long-chain fatty acids (2)

Answer 9

12 or more carbons

- most common and take longer time to digest

Question 10

2 carbon, zero double bond

Answer 10

butyric acid

Question 11

14 carbon, zero double bond

Answer 11

palmitic acid

Question 12

18 carbon, 1 double bond

Answer 12

oleic acid

Question 13

18 carbon, 2 double bond

Answer 13

linoleic acid

Question 14

18 carbon, 3 double bond

Answer 14

alpha-linolenic acid

Question 15

Degree of saturation of fatty acids

Answer 15

determined by whether carbons are held together by double or single bond

Question 16

Saturated fatty acids (5)

Answer 16

• all carbons on fatty acids are bound to hydrogen
• no double bonds
• solid at room temperature
• higher melting point
• tighter structure

Question 17

Unsaturated fatty acids (6)

Answer 17

• carbons on fatty acids form a double bond with each other, instead of binding to hydrogen
• Monounsaturated fatty acid (MUFA)
• Polyunsaturated fatty acid (PUFA)
• liquid at room temperature
• lower melting point
• looser structure

Question 18

Monounsaturated fatty acid (MUFA)

Answer 18

one double bond

Question 19

Polyunsaturated fatty acid (PUFA)

Answer 19

two or more double bonds

Question 20

Rancidity (3)

Answer 20

• spoiling of fats through oxidation
• double bonds are less stable than single bonds
• unsaturated fats become rancid father

Question 21

How to reduce fatty acid rancidity (3)

Answer 21

• antioxidants
• limit exposure to oxygen, heat, and light
• hydrogenation

Question 22

Location of double bond

Answer 22

location of first double bond from methyl (or omega) end of unsaturated fatty acids effects properties of fatty acids

Question 23

Omega-3 fatty acid

Answer 23

first double bond is between third and fourth carbons from omega end
- ex. alpha-linolenic acid

Question 24

Omega-6 fatty acid

Answer 24

first double bond is between sixth and seventh carbons from omega end
- ex. linoleic acid

Question 25

Shape of fatty acids

Answer 25

unsaturated fatty acids have two shapes based on position of hydrogen atoms around double bond - cis form and trans form

Question 26

Cis form (2)

Answer 26

hydrogens on same side of double bond | - boat structure

Question 27

Trans form

Answer 27

hydrogens on opposite sides of double bond

Question 28

Structure of triglyceride

Answer 28

glycerol backbone + three fatty acids

Question 29

Triglycerides (3)

Answer 29

- most common lipid - 95% of lipids - 3 fatty acids connected to glycerol backbone

Question 30

Triglycerides functions (4)

Answer 30

- add texture to baked goods - make eats tender - preserve freshness - stored as adipose tissue for energy

Question 31

Phospholipids (4)

Answer 31

- glycerol backbone, two fatty acids, a phosphate group, and nitrogen-containing compounds - hydrophilic tails - hydrophobic head - make up phospholipid bilayer in cell membrane