Complex Lipids

Question 1

Which type of fatty acid is typically esterified at the C1 position of glycerol in phospholipids?
A. Unsaturated fatty acid
B. Saturated fatty acid
C. Trans fatty acid
D. Polyunsaturated fatty acid

Answer 1

B. Saturated fatty acid

Question 2

The polar “head” of phospholipids is mainly composed of which groups?
A. Fatty acids and glycerol
B. Glycerol and phosphate
C. Phosphate and nitrogenous group
D. Fatty acids and phosphate

Answer 2

C. Phosphate and nitrogenous group

Question 3

Which phospholipid is most abundant in the outer leaflet of the plasma membrane?
A. Phosphatidylserine
B. Phosphatidylcholine
C. Phosphatidylethanolamine
D. Cardiolipin

Answer 3

B. Phosphatidylcholine

Question 3

What characteristic is unique to plasmalogens?
A. They contain two glycerol backbones
B. A vinyl ether linkage at the C1 position
C. They have no fatty acid tails
D. They lack phosphate groups

Answer 3

B. A vinyl ether linkage at the C1 position

Question 4

Cardiolipin is primarily found in which cellular membrane?
A. Nuclear membrane
B. Mitochondrial inner membrane
C. Plasma membrane
D. Endoplasmic reticulum

Answer 4

B. Mitochondrial inner membrane

Question 5

Which molecule is the backbone of sphingolipids?
A. Glycerol
B. Sphingosine
C. Palmitate
D. Ceramide

Answer 5

B. Sphingosine

Question 6

Sphingomyelin differs from glycerophospholipids because it has:
A. A glycerol backbone and fatty acids
B. A sphingosine backbone and phosphate group
C. Two fatty acid chains esterified to glycerol
D. Only carbohydrate groups as head groups

Answer 6

B. A sphingosine backbone and phosphate group

Question 6

Which of the following contains carbohydrate(s) attached to the sphingosine backbone?
A. Sphingomyelin
B. Phosphatidylcholine
C. Glycosphingolipids
D. Cardiolipin

Answer 6

C. Glycosphingolipids

Question 7

Gangliosides are characterized by having:
A. Phosphate head groups
B. Multiple sugar residues including sialic acid
C. Only glucose attached
D. No carbohydrate residues

Answer 7

B. Multiple sugar residues including sialic acid

Question 8

Which enzyme is responsible for adding palmitoyl CoA to serine to form 3-ketosphinganine in sphingolipid synthesis?
A. Ceramide synthase
B. Serine palmitoyltransferase
C. Sphingomyelinase
D. Glycosyltransferase

Answer 8

B. Serine palmitoyltransferase

Question 9

Which phospholipid serves as the major source of arachidonic acid for eicosanoid synthesis?
A. Phosphatidylserine
B. Phosphatidylcholine
C. Phosphatidylinositol
D. Phosphatidylethanolamine

Answer 9

C. Phosphatidylinositol

Question 10

What type of linkage connects the fatty acid to the sphingosine backbone in ceramide?
A. Ester linkage
B. Amide linkage
C. Ether linkage
D. Glycosidic linkage

Answer 10

B. Amide linkage

Question 11

Which phospholipid is zwitterionic and has no net charge at physiological pH?
A. Phosphatidylserine
B. Phosphatidylcholine
C. Phosphatidylinositol
D. Phosphatidylglycerol

Answer 11

B. Phosphatidylcholine

Question 12

The sugar present in glucocerebrosides is:
A. Galactose
B. Glucose
C. N-acetylgalactosamine
D. Sialic acid

Answer 12

B. Glucose

Question 13

Which lipid class is known for their antigenic properties related to blood groups?
A. Phospholipids
B. Glycosphingolipids
C. Sterols
D. Eicosanoids

Answer 13

B. Glycosphingolipids

Question 14

The main structural difference between globosides and gangliosides is:
A. Presence of phosphate group
B. Number of sugar residues
C. Presence of sialic acid residues
D. Type of fatty acid attached

Answer 14

C. Presence of sialic acid residues

Question 15

Which of the following describes the fatty acid composition of the glycerophospholipid bilayer region?
A. Saturated at C1 and unsaturated at C2
B. Unsaturated at C1 and saturated at C2
C. Saturated at both C1 and C2
D. Unsaturated at both C1 and C2

Answer 15

A. Saturated at C1 and unsaturated at C2

Question 16

What is the primary molecular feature that gives phospholipids their amphipathic nature?
A. Carbohydrate group
B. Polar head group and nonpolar fatty acid tails
C. Ester linkage of fatty acids
D. Phosphate group only

Answer 16

B. Polar head group and nonpolar fatty acid tails

Question 17

Which lipid structure serves as the precursor for platelet-activating factor (PAF)?
A. Phosphatidylserine
B. Plasmalogens
C. Phosphatidylcholine
D. Ceramide

Answer 17

B. Plasmalogens

Question 18

Which of the following is NOT a component of the fluid mosaic model of membranes?
A. Integral proteins
B. Cholesterol
C. Nucleic acids
D. Glycolipids

Answer 18

C. Nucleic acids

Question 19

What functional group is attached to the C3 position of glycerol in glycerophospholipids?
A. Phosphate group linked to a nitrogenous base
B. Two fatty acid chains
C. Sugar moiety
D. Hydroxyl group

Answer 19

A. Phosphate group linked to a nitrogenous base

Question 20

Which lipid is a major component of lung surfactant?
A. Phosphatidylglycerol
B. Dipalmitoylphosphatidylcholine (DPPC)
C. Cholesterol
D. Sphingomyelin

Answer 20

B. Dipalmitoylphosphatidylcholine (DPPC)

Question 21

Which molecule is formed by the linkage of two phosphatidic acid molecules via a glycerol backbone?
A. Phosphatidylinositol
B. Cardiolipin
C. Phosphatidylcholine
D. Plasmalogen

Answer 21

B. Cardiolipin

Question 22

Which structure is characteristic of sulfatides?
A. Ceramide linked to galactose sulfate
B. Ceramide linked to glucose
C. Glycerol backbone with sulfate group
D. Sphingosine linked to phosphocholine

Answer 22

A. Ceramide linked to galactose sulfate

Question 23

What is the charge of cardiolipin at physiological pH? A. Neutral B. Positive C. Negative (-2) D. Positive (+1)

Answer 23

C. Negative (-2)

Question 24

Which of the following is TRUE of phospholipid structure? A. Fatty acids are attached to carbons 1 and 2 B. Fatty acids are mostly unsaturated C. Phosphorylated alcohol is attached to carbon 4 D. Structural backbone contains 4 carbons

Answer 24

A. Fatty acids are attached to carbons 1 and 2

Question 25

Which is the unique structural feature of phosphatidylinositol? A. Fatty acid at C2 is almost exclusively arachidonic acid B. Fatty acid is attached via a vinyl ester linkage to the C1 hydroxyl group (plasmalogen) C. It is a neutral phosphoglycerol D. Made up of 2 molecules of phosphatidic acid linked via a glycerol molecule

Answer 25

A. Fatty acid at C2 is almost exclusively arachidonic acid

Question 26

Which nucleotide triphosphate serves as an immediate energy donor in phospholipid synthesis? A. ATP B. GTP C. UTP D. CTP

Answer 26

D. CTP

Question 27

Which enzyme cleaves the eicosanoid precursor from membrane phospholipids? A. Phospholipase A1 B. Phospholipase A2 C. Phospholipase C D. Phospholipase D

Answer 27

B. Phospholipase A2

Question 28

Which phospholipid gives rise to second intracellular messengers that mediate hormonal action? A. Phosphatidylcholine B. Phosphatidylethanolamine C. Phosphatidylinositol D. Phosphatidylserine

Answer 28

C. Phosphatidylinositol

Question 29

Decreasing levels of phosphatidylserine can be restored by which of the following mechanism pairs? A. Phosphatidylcholine base exchange B. Phosphatidylglycerol acylation C. Phosphatidylinositol decarboxylation D. phosphatidylethanolamine trimethylation

Answer 29

A. Phosphatidylcholine base exchange

Question 30

How does phosphatidylserine promote blood coagulation? A. Enhances vitamin K-mediated carboxylation of clotting factors B. Potentiates thrombin-mediated activation of clotting factors C. Provides a negatively charged activating surface D. Signals apoptotic cells to promote platelet activation

Answer 30

C. Provides a negatively charged activating surface

Question 31

Which phospholipid is the major source of the eicosanoid precursor? A. Phosphatidylcholine B. Phosphatidylethanolamine C. Phosphatidylinositol D. Phosphatidylserine

Answer 31

C. Phosphatidylinositol

Question 32

Which enzyme synthesizes prostaglandins and thromboxanes from the precursor arachidonic acid? A. Cyclooxygenase B. Cytochrome P450 epoxygenase C. Glutathione s-transferase D. Lipoxygenase

Answer 32

A. Cyclooxygenase

Question 33

Which of the following eicosanoids functions as a potent platelet aggregator? A. Leukotriene B4 B. Prostaglandin D2 C. Prostaglandin F2 D. Thromboxane A2

Answer 33

D. Thromboxane A2

Question 34

Which eicosanoid maintains patency of the ductus arteriosus? A. Leukotriene C4 B. Prostaglandin E2 C. Prostacyclin (PGI2) D. Thromboxane A2

Answer 34

B. Prostaglandin E2

Question 35

Which fatty acid is the major precursor of the eicosanoids? A. 18△9, 12 B. 18△6, 9, 12 C. 20△5, 8, 11, 14 D. 18△5, 8, 11, 14, 17

Answer 35

C. 20△5, 8, 11, 14

Question 36

Which type of fatty acid is arachidonic acid classified as? A. Omega-3 B. Omega-5 C. Omega-6 D. Omega-9

Answer 36

C. Omega-6

Question 37

What type of eicosanoids are synthesized by the lipoxygenase pathway? A. Prostaglandins and Thromboxanes B. Leukotrienes and Lipoxins C. DiHETEs and HETEs D. Isoprostanes

Answer 37

B. Leukotrienes and Lipoxins

Question 38

Which nonsteroidal anti-inflammatory drug (NSAID) primarily inhibits COX-1? A. Acetaminophen B. Aspirin C. Celecoxib D. Ibuprofen

Answer 38

B. Aspirin

Question 39

Which amino acid triad is the precursor for the synthesis of slow-reacting substance of anaphylaxis (leukotrienes)? A. Glutamate, glycine, cysteine B. Phenylalanine, methionine, serine C. Threonine, valine, isoleucine D. Tryptophan, alanine, leucine

Answer 39

A. Glutamate, glycine, cysteine

Question 40

Thromboxane A2 leads to platelet ____, whereas prostacyclin PGI2 leads to platelet ____. A. Aggregation, inhibition B. Inhibition, aggregation

Answer 40

A. Aggregation, inhibition

Question 41

LTC4, LTD4, and ____ are inflammatory mediators that cause severe bronchoconstriction. A. LTA4 B. LTB4 C. LTE4 D. LTF4

Answer 41

C. LTE4

Question 42

Which enzyme deficiency causes Tay-Sachs disease? A. Beta-glucosidase B. Hexosaminidase A C. Sphingomyelinase D. Alpha-galactosidase A

Answer 42

B. Hexosaminidase A

Question 43

What accumulates in Gaucher disease? A. Glucocerebroside B. Ganglioside GM2 C. Sphingomyelin D. Ceramide sulfate

Answer 43

A. Glucocerebroside

Question 44

Niemann-Pick disease types A and B result from deficiency of: A. Hexosaminidase A B. Sphingomyelinase C. Beta-galactosidase D. Arylsulfatase A

Answer 44

B. Sphingomyelinase

Question 45

Deficiency of which enzyme causes Metachromatic leukodystrophy? A. Beta-glucocerebrosidase B. Arylsulfatase A C. Hexosaminidase B D. Beta-galactosidase

Answer 45

B. Arylsulfatase A

Question 46

Krabbe disease is characterized by deficiency of: A. Galactocerebrosidase B. Glucocerebrosidase C. Gangliosidase D. Sphingomyelinase

Answer 46

A. Galactocerebrosidase

Question 47

Which enzyme deficiency underlies Gaucher disease? A. Beta-glucosidase B. Hexosaminidase A C. Arylsulfatase A D. Alpha-galactosidase A

Answer 47

A. Beta-glucosidase

Question 48

Accumulation of ceramide trihexoside is seen in: A. Fabry disease B. Tay-Sachs disease C. Niemann-Pick disease D. Krabbe disease

Answer 48

A. Fabry disease

Question 49

Hurler syndrome involves accumulation of: A. Glucocerebrosides B. Mucopolysaccharides C. Gangliosides D. Cerebrosides

Answer 49

B. Mucopolysaccharides

Question 50

Hurler syndrome results from deficiency of: A. Alpha-L-iduronidase B. Beta-glucosidase C. Hexosaminidase A D. Arylsulfatase B

Answer 50

A. Alpha-L-iduronidase

Question 51

Cardiolipin functions primarily to: A. Stabilize mitochondrial membranes B. Act as second messenger precursor C. Promote blood coagulation D. Bind hormones

Answer 51

A. Stabilize mitochondrial membranes

Question 52

Phosphatidylinositol serves as precursor for: A. IP3 and DAG B. cAMP and cGMP C. ATP and ADP D. FAD and NAD

Answer 52

A. IP3 and DAG

Question 53

Plasmalogens are abundant in: A. Lung tissue B. Myelin sheath C. Liver D. Kidney

Answer 53

B. Myelin sheath

Question 54

Glycosphingolipids chiefly function in: A. Signal transduction B. Cell recognition and antigenicity C. Energy storage D. Membrane fluidity

Answer 54

B. Cell recognition and antigenicity