Lipids I

Question 1

are family of biomolecules with seemingly unrelated structures. They are sparingly soluble in water and have diverse biological functions.

Answer 1

Lipids

Question 2

fatty acids commonly found in animals as________,which are stored mainly in adipose cells (adipocytes)

Answer 2

triacylglycerols

Question 3

CLASSIFICATION OF LIPIDS

triacylglycerols

Answer 3

Energy-storage lipids

Question 4

CLASSIFICATION OF LIPIDS

phospholipids, sphingoglycolipids,
and cholesterol

Answer 4

Membrane lipids

Question 5

CLASSIFICATION OF LIPIDS

bile acids

Answer 5

Emulsification lipids

Question 6

CLASSIFICATION OF LIPIDS

steroid hormones and eicosanoids

Answer 6

Chemical messenger lipids

Question 7

CLASSIFICATION OF LIPIDS

biological waxes

Answer 7

Protective-coating lipids

Question 8

CLASSIFICATION OF LIPIDS

lipoproteins

Answer 8

Transport lipids

Question 9

Simple lipids
a. – yield fatty acids and glycerol
b. – yield fatty acids and long chain alcohol

Answer 9

fats and oils

waxes

Question 10

Compound lipids
a. – yield fatty acids, glycerol or sphingosine,
phosphoric acid and an amino alcohol or amino acid
b. – yield fatty acids, sphingosine and a carbohydrate upon hydrolysis.

Answer 10

phospholipids

glycolipids

Question 11

is a fatty acid with a carbon chain in which two or more carbon–carbon double bonds are present.

Answer 11

polyunsaturated fatty acid

Question 12

• an unsaturated fatty acid with its
  endmost double bond three carbon atoms away from its
  methyl end.

Answer 12

Omega (ω)-3 fatty acids

Question 13

• an unsaturated fatty acid with its
  endmost double bond six carbon atoms away from its methyl end.

Answer 13

Omega (ω)-6 fatty

Question 14

precursor for the synthesis of prostacyclin, which inhibits clumping of platelets and thus reduces clot formation.

Answer 14

EPA

Question 15

one of the major fatty acids in the phospholipids of sperm and brain cells, as well as in the retina; it has also been shown to reduce triglyceride levels, although the mechanism is not understood.

Answer 15

DHA

Question 16

seems to reduce the incidence of cardiovascular disease, however it is not clear whether it acts alone or because it is the precursor of DHA and EPA.

Answer 16

ALA

Question 17

_______ is also an essential fatty acid, required for the synthesis of _______, the precursor for many prostaglandins.

Answer 17

Linoleic acid

arachidonic acid

Question 18

are precursors of prostaglandins that exhibit anti-inflammatory effects

Answer 18

Omega-3 fatty acids

Question 19

are precursors to prostaglandins that have inflammatory effects.

Answer 19

omega-6 fatty acids

Question 20

• are esters composed of three fatty acids joined to the trihydroxy alcohol, glycerol.

Answer 20

Triglycerides or triacylglycerols (TAG)

Question 21

– solid at room temperature
– obtained from animal sources, hence, ‘animal fats’
– contain greater proportion of saturated fatty acids (those with single Bonds only)

Answer 21

FATS

Question 22

• liquid at room temperature
• of plant origin, hence, ‘vegetable oils’
• contain greater percentage of unsaturated fatty acids (those with one or more double bonds)

Answer 22

OILS

Question 23

The yellow color of butter is due to the presence of the
pigment ______

Answer 23

carotene

Question 24

Storage site of triacylglycerols in animals

Answer 24

Adipose tissues (adipocytes/fat cells)

Question 25

Addition of H2 to double bonds of unsaturated fatty acids in lipids, converting them to single bonds of saturated fatty acids.

Answer 25

Hydrogenation

Question 26

Addition of water to ester bonds of lipids in the presence of strong acids or digestive enzymes called _______.

Answer 26

Hydrolysis

Lipases

Question 27

Reaction of lipids with a strong base (alkaline hydrolysis) to give glycerol and salts of the fatty acids (called soaps).

Answer 27

Saponification

Question 28

Double bonds in triacylglycerols are subject to oxidation with oxygen in air (an oxidizing agent ) - Leads to C=C breakage

Answer 28

Oxidation

Question 29

• fat and oil develops a disagreeable odor caused by hydrolysis and oxidation.

Answer 29

Rancidity

Question 30

Butter is particularly susceptible to rancidity because it contains many of the lower molar mass acids (butyric, caproic) all of which have offensive odors. Under moist and warm conditions, hydrolysis of the ester linkages occurs, liberating the volatile acids.

Answer 30

Hydrolytic rancidity

Question 31

Occurs in triglycerides containing unsaturated fatty acids.

Answer 31

Oxidative rancidity

Question 32

are compounds added to foods in very small amounts (0.01–0.001%) to suppress rancidity. They have a greater affinity for oxygen than the lipid to which they are added and thus function by preferentially depleting the supply of adsorbed oxygen.

Answer 32

Antioxidants

Question 33

is a monoester of a long-chain fatty acid and a long-chain alcohol.

Answer 33

biological wax

Question 34

found in the surfaces of leaves and stems and serve to protect the plant from dehydration and from invasion by harmful organisms.

Answer 34

Plant waxes

Question 35

also serve as protective coatings; found on the surface of feathers, skin, and hair and help keep these surfaces soft and pliable.

Answer 35

Animal waxes