Lipids

Question 1

What are some examples of lipids?

Answer 1

canola oil, distillers grains, corn oil, flax seeds, lard, megalac (rumen bypass).

Question 2

What are lipids?

Answer 2

ether extracts in proximate analysis
organic compounds contains C, H, O
-insoluble in water
-soluble in organic solvents
Ex: acetone, methanol

Question 3

Lipids in plant tissue

Answer 3

lipid content of most plants is relatively low except for oil seeds (canola, soybean, sunflower, and safflower oils)

Question 4

lipids in animal tissue

Answer 4

relatively large amounts in animal tissue
-adipose tissue
-major form of energy storage
amount is variable
-diet, age, physiological state

Question 5

Major function of fatty acids/lipids in the body

Answer 5

1) universal component of all cell membranes
- -lipid bilayer
2) long term energy storage
- -adipocytes
3) insulation
- -subcutaneous fat
4) component of enzyme systems
- -coenzymes Q
5) component of steroid hormones
- -estrogen, testosterone
6) fat soluble vitamin absorption, synthesis
- -vitamin A,D,E,K

Question 6

Examples of simple lipids

Answer 6

1) fatty acids
2) acylglycerols
3) waxes
- sterol and nonsterol esters

Question 7

examples of compound lipids

Answer 7

phospholipids, lipoproteins, glycolipids

Question 8

single bond=

Answer 8

saturated

Question 9

double bond=

Answer 9

unsaturated

Question 10

What is fatty acid nomenclature based on?

Answer 10

1) number of carbons (chain size)
2) types of double bonds
3) positions of double bonds relative to the methyl (ω) or carboxyl end of the fatty acid

Question 11

omega nomenclature

Answer 11

Fatty acids categorized into groups based on
where the first double bond is located
relative to the omega (ω)/methyl end

“n” system

Question 12

delta nomenclature

Answer 12

Based on positions and type(s) of double
bond(s) relative to the delta (Δ)/carboxyl
end of the fatty acids

Question 13

classification of fatty acids

Answer 13

Just as with nomenclature its based on:

a. Number of carbon atoms (chain length)
b. Presence/absence of double bonds between C atoms
c. Number of double bonds between C atoms
d. Configuration of double bonds

Question 14

Melting point is the highest and greatest in what FA?

Answer 14

long chain fatty acid

Question 15

saturated fatty acids (SFA)

Answer 15

only single carbon-carbon bonds

Question 16

monounsaturated FA (MUFA)

Answer 16

1 double bond

Question 17

polyunsaturated FA (PUFA)

Answer 17

more than 1 double bond

Question 18

saturated fats are what at room temperature?

Answer 18

solid

Question 19

monounsaturated fats are what at room temperature?

Answer 19

thick liquid or soft solid

Question 20

polyunsaturated fats are what at room temperature?

Answer 20

liquid

Question 21

does the cis or trans configuration have the lower chemical stability and melting point?

Answer 21

cis fatty acids

Question 22

what are the two major types of PUFA?

Answer 22

2 major types of PUFA
❑ Omega-6 and omega-3 fatty acids
a. Linoleic acid (simplest omega-6 FA)
b. α-Linolenic acid (simplest omega-3 FA)
c. Linoleic & α-Linolenic acids = Essential fatty
acids

Question 23

What are essential fatty acids?

Answer 23

Essential FA
a. Linoleic acid or 18:2 Δ
9,12 (n-6)
b. α-Linolenic acid or 18:3 Δ
9,12,15 (n-3)
❑ Not produced in the body because animals lack the
necessary Δ
12 and Δ
15 desaturase enzymes

Question 24

What are the functions of essential fatty acids?

Answer 24

Source of energy
b. Important structural components
c. Precursors to bioactive lipid mediators
❑ Eicosanoids = “signaling molecules”
❑ E.g., Prostaglandins; PGF2α = uterine contraction

Question 25

symptoms of EFA Deficiency

Answer 25

Slow growth

b. Compromised immune function
c. Reproductive failure
d. Gastrointestinal problems
e. Irritated & flaky skin

Question 26

What are the physiological functions of Omega-3 and Omega-6 FA?

Answer 26

Brain development

ii. Anti-carcinogenic
iii. Anti-atherosclerosis

Question 27

What are aglycerols?

Answer 27

Glycerol bound to fatty acid(s) through an ester

linkage (esters of glycerol)

Question 28

What are the functions of triglycerides?

Answer 28

Energy storage/production

ii. Insulation
iii. Protection of organs
iv. Provide essential fatty acids for body function

Question 29

triglycerides as an energy reserve

Answer 29

Adipose tissue
❑ Made up of adipocytes
or “fat cells”
❑ Subcutaneous or visceral

Question 30

B-oxidation of mobilized FA

Answer 30

Yields Acetyl-CoA:
i. Oxidized to CO2 in TCA cycle
❑ Also yields FADH2, NADH (oxidized to yield ATP)
ii.Used for ketone body synthesis (liver, muscle)
❑ Source of energy in brain, kidney, liver, skeletal
muscle

Yields FADH2, NADH:
❑ Co-enzymes involved in the mitochondrial electron
transport system
❑ Oxidized to yield ATP

Question 31

What is a sterol?

Answer 31

steroid alcohol

Question 32

What does a sterol do?

Answer 32

Lipids with distinctive multi-ring structure
b. Occur naturally in plants, animals
❑ Component of cell membranes
❑ Cholesterol = most familiar type of animal sterol

Question 33

What is a sterol ester?

Answer 33

Chemical compound of a sterol molecule bonded to a
fatty acid via ester linkage
❑ E.g., Cholesteryl ester
❑ Component of cell membranes
❑ In blood circulation

Question 34

cholesterol sources

Answer 34

Foods of animal origin
b. De novo synthesis
❑ Primarily in the liver
❑ Influenced by genetics + diet

Question 35

functions of phospholipids

Answer 35

Major components of cell membranes
❑ Amphipathic property

Play a key role in digestion, absorption,
transport of lipids

Found naturally in most foods
❑ E.g., Phosphatidylcholine or “Lecithin”
a. Stabilizer in food (e.g., mayonnaise, ice cream)
b. Found in the brain
❑ Important in neural development and function

Question 36

What is an example of lipoprotein?

Answer 36

Chylomicrons
❑ Carriers of lipids in blood
Hydrophilic
surface monolayer
❑ Hydrophobic core

Question 37

what are glycolipids?

Answer 37

Grasses rich in glycolipids
❑ Major source of lipids for animals consuming forages
b. Cerebrosides and gangliosides
❑ Subtypes of glycolipids
❑ Found predominantly in the brain, nerve tissue