Question 1

Tay-Sachs disease is the result of an inborn error of metabolism of

Accepted Answer

A)   histidine.
B)   cholesterol.
C)   ganglioside.
D)   lactose.
E)   cerebroside.F) B) and C)
G) A) and B)

Question 2

Which one of the following statements concerning lipoprotein metabolism is CORRECT?

Accepted Answer

A)   High density lipoprotein (HDL)  contains more than 20% by weight of lipid.
B)   Very low density lipoprotein (VLDL)  contains less than 20% of triglyceride.
C)   Very low density lipoprotein synthesis is inhibited by high carbohydrate diets.
D)   Low density lipoprotein (LDL)  has a half life of several hours.
E)   Synthesis of chylomicrons is inhibited by ketone bodies.F) B) and D)
G) A) and C)

Question 3

In the synthesis of cholesterol from lanosterol

Accepted Answer

A)   pyrophosphorylated intermediates are used.
B)   an anaerobic environment is required.
C)   three carbons are lost as propionyl-CoA.
D)   the side chain becomes saturated.
E)   the number of rings decreases from five to four.F) A) and B)
G) C) and D)

Question 4

An accumulation of gangliosides in brain tissue most likely arises from a deficiency of lysosomal

Accepted Answer

A)   acyltransferase.
B)   aryl sulfatase.
C)   hexosaminidase.
D)   phospholipase A2.
E)   sphingomyelinase.F) A) and B)
G) D) and E)

Question 5

The action of a phospholipase C on a phospholipid substrate may yield

Accepted Answer

A)   glycerol, fatty acids, inositol 1,4,5-trisphosphate.
B)   monoacylglycerol, fatty acid, phosphocholine.
C)   diacylglycerol, phosphoethanolamine.
D)   phosphoceramide, choline.E) All of the above
F) A) and B)

Question 6

Squalene is formed

Accepted Answer

A)   by a phosphorylation reaction.
B)   by a reductive condensation reaction.
C)   by an oxidation.
D)   from lanosterol.E) B) and C)
F) B) and D)

Question 7

Which of the following apoproteins serves as a cofactor (activator)  for lecithin: cholesterol acyltransferase (LCAT) ?

Accepted Answer

A)   APO AI
B)   APO B-100
C)   APO CII
D)   APO EE) B) and C)
F) A) and D)

Question 8

Which of the following statements is true concerning cholesterol metabolism?

Accepted Answer

A)   HMG-CoA synthase catalyzes the reaction between two molecules of acetyl-CoA.
B)   Mevalonate is produced by the reduction of HMG-CoA.
C)   cholesterol synthesis occurs in the mitochondria of cells.
D)   Squalene is formed by reduction of lanosterol.
E)   HMG-CoA reductase is activated by cholesterol.F) C) and E)
G) None of the above

Question 9

In the synthesis of prostaglandins and thromboxanes

Accepted Answer

A)   arachidonic acid of the cytosol serves as the primary precursor.
B)   PG synthase uses 2 molecules of oxygen to generate the endoperoxide PGG2.
C)   PGE2 synthesis would be inhibited by aspirin but thromboxane synthesis would not be affected.
D)   PGH2 is the precursor of PGE2 but PGI2 is the precursor of TXA2.
E)   all tissues have the capacity to synthesize all of the prostaglandins.F) None of the above
G) A) and B)

Question 10

To be defined as a ganglioside, a lipid substance isolated from nerve tissue must contain in its structure

Accepted Answer

A)   an N-acyl fatty acid derivative of sphingosine plus a hexose.
B)   N-acetylneuraminic acid (NAN
A)  , N-acetylgalactosamine, a hexose, long chain fatty acid and sphingosine.
C)   N-acetylneuraminic acid (NAN
A)  , a hexose, a fatty acid and sphingosine.
D)   NANA, a hexose, a fatty acid, sphingosine and phosphatidylcholine.
E)   a 9 carbon 3-deoxy-5-amino sugar called neuraminic acid, sphingosine and ethanolamine.F) B) and D)
G) A) and D)

Question 11

The primary metabolic defect in the disease familial hypercholesterolemia is

Accepted Answer

A)   altered prostaglandin synthesis.
B)   decreased lysosomal enzyme activity.
C)   decreased receptor?mediated endocytosis.
D)   increased formation of modified low density lipoproteins.
E)   increased hormone-sensitive lipid mobilization.F) A) and C)
G) B) and D)

Question 12

Which of the following compounds is a glycolipid?

Accepted Answer

A)   Sphingomyelin
B)   phosphatidyl choline
C)   cholesterol
D)   Ganglioside
E)   phosphatidyl serineF) A) and B)
G) C) and D)

Question 13

Phosphatidate phosphatase is involved in the synthetic pathway for

Accepted Answer

A)   choline.
B)   glycerol phosphate.
C)   phosphatidic acid.
D)   cholesterol.
E)   triglycerides.F) A) and B)
G) None of the above

Question 14

Select the lipid fraction in blood which is most rapidly cleared?

Accepted Answer

A)   VLDL
B)   HDL
C)   chylomicrons
D)   LDL
E)   All are cleared at approximately same rate.F) C) and E)
G) C) and D)

Question 15

Lipoprotein lipase is

Accepted Answer

A)   an intracellular enzyme.
B)   stimulated by cAMP.
C)   stimulated by epinephrine.
D)   stimulated by one of the apolipoproteins found in VLDL.
E)   the stimulus for mobilization of stored triglycerides from adipose tissue.F) C) and D)
G) A) and B)

Question 16

In the metabolism of cholesterol in the human

Accepted Answer

A)   cholesterol conversion to bile salts involves shortening of the side chain of cholesterol.
B)   plasma cholesterol readily exchanges with the brain cholesterol.
C)   plasma cholesterol is entirely in the form of cholesterol esters.
D)   cholesterol can be oxidized to carbon dioxide and water.
E)   cholesterol is synthesized only in the liver.F) A) and C)
G) A) and D)

Question 17

The substrate for the synthesis of prostaglandins and leukotrienes is released from endogenous

Accepted Answer

A)   gangliosides.
B)   plasmalogen.
C)   phosphatidylcholine.
D)   cholesteryl oleate.
E)   ceramide.F) C) and D)
G) All of the above

Question 18

Of the apoproteins listed below, which one is recognized by the LDL receptor?

Accepted Answer

A)   Apoprotein D
B)   Apoprotein C II
C)   Apoprotein B?48
D)   Apoprotein B?100
E)   Apoprotein A?IF) All of the above
G) C) and E)

Question 19

A characteristic feature common to the degradation of most sphingolipids, including gangliosides, is

Accepted Answer

A)   catalysis by lysosomal enzymes.
B)   catalysis by peroxisomal enzymes.
C)   feedback regulation by ceramide.
D)   hormonal regulation by glucocorticoids.
E)   participation of nucleotide intermediates.F) C) and E)
G) All of the above

Question 20

All the statements concerning phosphatidyl choline (lecithin)  are TRUE EXCEPT

Accepted Answer

A)   It possesses three fatty acyl groups in its structure.
B)   It can be synthesized using S-adenosyl methionine as an intermediate.
C)   It can be synthesized using a CDP-derivative as an intermediate.
D)   It is found in most lipoproteins.
E)   It is an integral part of membranes.F) B) and D)
G) All of the above

Exam 18: Lipid Metabolism II: Pathways of Metabolism of Special Lipids

All the statements concerning phosphatidyl choline (lecithin) are TRUE EXCEPT

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Lipoprotein lipase is

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In the metabolism of cholesterol in the human

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To be defined as a ganglioside, a lipid substance isolated from nerve tissue must contain in its structure

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A characteristic feature common to the degradation of most sphingolipids, including gangliosides, is

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Tay-Sachs disease is the result of an inborn error of metabolism of

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The substrate for the synthesis of prostaglandins and leukotrienes is released from endogenous

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In the synthesis of prostaglandins and thromboxanes

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Squalene is formed

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Which of the following apoproteins serves as a cofactor (activator) for lecithin: cholesterol acyltransferase (LCAT) ?

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The primary metabolic defect in the disease familial hypercholesterolemia is

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An accumulation of gangliosides in brain tissue most likely arises from a deficiency of lysosomal

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Which of the following compounds is a glycolipid?

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In the synthesis of cholesterol from lanosterol

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Phosphatidate phosphatase is involved in the synthetic pathway for

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Of the apoproteins listed below, which one is recognized by the LDL receptor?

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Which of the following statements is true concerning cholesterol metabolism?

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Select the lipid fraction in blood which is most rapidly cleared?

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The action of a phospholipase C on a phospholipid substrate may yield

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Which one of the following statements concerning lipoprotein metabolism is CORRECT?

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