Lipids: Properties and Classes 21

Question 1

What is one common characteristic with all lipids??

Answer 1

All are not water soluble. (Therefore fat acts as a barrier)

Question 2

What are some major biological functions of lipids in the body?

Answer 2

1. Barrier
2. Hormones
3. Immune function- Precursor to eicosanoids
4. Insulation
5. Energy storage and source (9kcal/g)
6. Major component of cell membranes

Question 3

Non-esterified FA or FFA

Answer 3

Head: carboxylic acid, Tail CH chain

• 99% in plasma bound to albumin or else toxic
• Fat break down occurs mostly in the liver and adipose tissue.
• Insulin inhibits FFA release
• Increase FFA during starvation. (Breaking down fats)

Question 4

What are the major Classifications?

Answer 4

SCFA: 14
The degree of saturation is also important…
Saturated: no double bonds, Monounsaturated: one double bond.
Polyunsaturaed: More than 1 double bond.

Question 5

What is the most common FA found?

Answer 5

Mostly 16Chain, even carbon (Add by 2C during synthesis). Most common is 14-18C.

Question 6

Notation: Omega 18: 2 w6

Answer 6

Count from CH3 end.

Question 7

Miller notation 18: 2 n-6

Answer 7

Subtract n from total C to get how many away from the COOH end.

Question 8

What is the most common way to find FA?

Answer 8

Most are in cis formation. However if in trans they are usually monounsaturated FA. With few polyunsaturated trans FA. Trans is due to biohydrogenation of ruminant animals.

Question 9

Saturated FA nomenclature: Do from C12-C18

Answer 9

C12: Lauric acid, coconut oil, palm oil
C14:Myristic acid, coconut oil, palm oil
C16:Palmitic acid, palm oil
C18:Stearic acid , most animal fats

Question 10

Unsaturated FA nomenclature: C16-C22

Answer 10

C16:1w7 Palmitoleic acid  
SOURCE: seafood, beef
C18:1w9 Oleic acid 
SOURCE: olive oil canola oil
C18:2w6 Linoleic acid
SOURCE: sunflower, safflower oils 
C18:3w3 Linolenic acid
SOURCE: soybean and canola oil, flaxseeds
C20:4w6 Arachiodonic acid 
SOURCE: eggs, most animal fats
C20:5w3 Eicosapentaenoic acid (EPA)
Seafood
C22:6w3 Docosahexoenoic acid (DHA)
Seafood

Question 11

What are the benefits of omega 3 linolenic acid ?

Answer 11

Reduces the risk of heart disase and stroke. Helps prevent blood clots, lowers blood pressure. Great sources of linolenic acid are oils such as flaxseed and canola oil, nuts and seed such as walnuts, flaxseeds. vegetables such as soybeans.
EPA and DHA seafood: oysters.

Question 12

What are some sources of omega 6?

Answer 12

Vegetable oils, safflower, sunflower oils. Arachodonic acid: sources are eggs and meat and poultry

Question 13

What do you want the omega 6: omega 3 ratio to be?

Answer 13

Ideal is there’s more omega 6 than omega 3. 5:1 kind of deal. They compete for the same enzymes and their actions often oppose each other. Increasing omega-3 in the diet is best! Not reducing omega 6 b/c it’s still needed in the diet.

Question 14

Recommendation of linolenic acid?

Answer 14

female: AI is 1.1g/day and male is 1.6g/day

Question 15

Recommendation of linoleic aicd?

Answer 15

Female: AI 15g/day, men 17g/day

Question 16

Glycerolid?

Answer 16

Glycerol backbown attached by ester linage to a FA. Alcohol + acid
C-OH HOOC^^^^^^^^^^^
COC=O^^^^^^^^^

Question 17

Simple TG

Answer 17

All the same FA on the glycerol

Question 18

Complex TG

Answer 18

Different FA on the glycerol (more common)

Question 19

What are in position sn-1 and sn-3?

Answer 19

Saturated FA..therefore sn-2 is usually unsaturated FA.

Question 20

What makes a fat short and liquid at room temperature? (Increase fluidity)

Answer 20

decrease chain length and increase double bonds.

Coconut oil

Question 21

What causes a fat to decrease stability and be readily oxidized?

Answer 21

short chain length and more double bonds

Question 22

Sources of SFA

Answer 22

coconut oil, butter, beef tallow, bacon,

Question 23

Sources of MUFA

Answer 23

olive oil, coconut oil, peanut oil

Question 24

Sources of PUFA

Answer 24

safflower oil, sunflower oil, soybean oil, canola oil for omega-3.

Question 25

Hydrogenation of TG..what happens

Answer 25

Add on H’s to decrease the unsaturated FA

Changes MP, mouth feel and flow.

Question 26

Bio product of hydrogenation?

Answer 26

Trans= bad. partial hydrogenation. Trans often increases LDL and decreases HDL.

Question 27

Sources of trans fat

Answer 27

fast food, fried foods, shortening chips

Question 28

Glycerophospholipids..why are they important?

Answer 28

Phospholipid bilayer.
They have hydrophilic head and hydrophobic tails.
Control passage in and out of compounds/ cells

Question 29

What is the structure of a glycerophospholipid?

Answer 29

glycerol back bone with sn-1 and sn2 FA and phosphate group in sn-3.
sn-1 saturated and sn-2 unsaturated

Question 30

What is the major phospholipid used in food industry?

Answer 30

Phosphohatidyl cholrine as a emulsifier (lecithin)

Question 31

Glycosphingolipids structure?

Answer 31

amino alcohol and FA + sugar

Question 32

What is the function of a glycosphinolipid?

Answer 32

Cell surface antigens, receptors. Lots in mylein sheath.

Question 33

Cholesterol. What is the main form in the body?

Answer 33

Cholesterol ester- cholesterol + FA (main form)

or free cholesterol

Question 34

What is the importance of cholesterol in the body?

Answer 34

It modulates membrane compressiblitity, permeability, fusibility, thickness and organization.

Question 35

What are plant sterols called?

Answer 35

beta-sitosterol

Question 36

What is the relationship between cholesterol and bile?

Answer 36

Bile acids are formed from cholesterol.
Once cholesterol are conjugated with taurine or glycine in the liver they are secreted in the bile.
Aid in digestion and absorption of fat and fat soluble vitamins in the intestine.