Question 1

The synthesis of the glycosphingolipids begins with the reaction of either UDP-glucose or UDP-galactose with _____________.

Accepted Answer

A)  ceramide
B)  sphinganine
C)  sphingosine
D)  sphingomyelin
E)  none of the above

Question 2

Tay-Sachs disease is caused by a deficiency of __________ which results in an accumulation of ___________.

Accepted Answer

A)  sphingomyelinase;sphingomyelin
B)  ceramidase;ceramide
C)   α\alphaα -galactosidase A;GM1 ganglioside
D)  lysosomal N-acetylhexosaminidase A;GM2 ganglioside
E)   β\betaβ -glucosidase;glucosylceramide  D

Question 3

Show the reaction catalyzed by 3-hydroxy-3-methylglutrayl-CoA reductase.

Accepted Answer

The answer of Show the reaction catalyzed by 3-hydroxy-3-methylglutrayl-CoA reductase....

Question 4

Which of the following phospholipids is produced in eukaryotes but not prokaryotes?

Accepted Answer

A)  phosphatidylglycerol
B)  phosphatidylserine
C)  phosphatidylethanolamine
D)  phosphatidylinositol
E)  none of the above D

Question 5

7-dehydrocholesterol reacts with _________ to produce cholecalciferol (vitamin D3)

Accepted Answer

A)  UV light
B)  visible light
C)  NADPH
D)  NAD+
E)  none of the above

Question 6

Which of the following is used to activate phosphatidic acid for conversion to various phospholipids?

Accepted Answer

A)  ATP
B)  UTP
C)  CTP
D)  GTP
E)  TTP

Question 7

Show the products of the following reaction and name them:

Accepted Answer

The answer of Show the products of the following reaction...

Question 8

The synthesis of 1 molecule of cholesterol requires _____ molecules of isopentenyl pyrophosphate,with each molecule of isopentenyl pyrophosphate requiring _____ molecules of acetyl-CoA.

Accepted Answer

A)  4;2
B)  5;2
C)  6;2
D)  5;3
E)  6;3

Question 9

Phospholipids are synthesized in the ___________,then transferred to the ____________ via transport vesicles.

Accepted Answer

A)  smooth endoplasmic reticulum;Golgi complex
B)  rough endoplasmic reticulum;smooth endoplasmic reticulum
C)  smooth endoplasmic reticulum;lysosome
D)  Golgi complex;smooth endoplasmic reticulum
E)  Golgi complex;cell membrane

Question 10

How is the activity of HMG-CoA reductase reduced?

Accepted Answer

A)  allosteric inhibition by cholesterol
B)  ubiquitination in response to sterol accumulation resulting in proteolysis
C)  serine phosphorylation by an insulin-activated protein kinase
D)  tyrosine phosphorylation by AMPK
E)  none of the above

Question 11

Which of the following correctly identifies the order of carbocations found in the mechanism of squalene synthase?

Accepted Answer

A)  tertiary carbocation;allylic carbocation;tertiary cyclopropylcarbinyl carbocation
B)  tertiary carbocation;tertiary cyclopropylcarbinyl carbocation;allylic carbocation
C)  allylic carbocation;tertiary cyclopropylcarbinyl carbocation;tertiary carbocation
D)  allylic carbocation;tertiary carbocation;tertiary cyclopropylcarbinyl carbocation
E)  tertiary cyclopropylcarbinyl carbocation ;allylic carbocation;tertiary carbocation

Question 12

Squalene epoxidase is an example of a mixed function oxidase,meaning that it uses both _______ and _______ as substrates.

Accepted Answer

A)  ATP;NADPH
B)  ATP;O2
C)  NAD+;NADPH
D)  O2;NAD+
E)  O2;NADPH

Question 13

Which of the following forms of vitamin A is covalently attached to a lysine residue of the protein opsin to form the complex called rhodopsin?

Accepted Answer

A)  all-trans-retinal
B)  11-cis-retinal
C)  all-trans-retinoic acid
D)  all-trans-retinol
E)   β\betaβ -carotene

Question 14

In prokaryotes,_________ is used exclusively as the precursor for phosphatidic acid while in eukaryotes,_________is one of three possible precursors.

Accepted Answer

A)  diacylglycerol;glycerol-3-phosphate
B)  glycerol-3-phosphate;dihydroxyacetone phosphate
C)  dihydroxyacetone phosphate;glycerol-3-phosphate
D)  3-phosphoglycerate;diacylglycerol
E)  dihydroxyacetone phosphate;diacylglycerol

Question 15

What is the term for the molecule shown below?

Accepted Answer

A)  platelet-activating factor
B)  1-alkyl-2-acetylglcerophosphoethanolamine
C)  serine plasmologen
D)  choline plasmologen
E)  ethanolamine plasmologen E

Question 16

Which of the following is accomplished in one enzyme catalyzed reaction?

Accepted Answer

A)  progesterone to androstenedione
B)  17-hydroxyprogesterone to cortisol
C)  progesterone to aldosterone
D)  androstenedione to testosterone
E)  androstenedione to estradiol

Question 17

In eukaryotes,the conversion of DHAP to 1-acylglycerol-3-phosphate is a two-step process.Show the reactants and products missing in the following scheme.

Accepted Answer

The answer of In eukaryotes,the conversion of DHAP to 1-acylglycerol-3-phosphate...

Question 18

Which of the following is the regulatory step in cholesterol synthesis?

Accepted Answer

A)  HMG-CoA synthase
B)  HMG-CoA lyase
C)  HMG-CoA reductase
D)  squalene synthase
E)  squalene epoxidase

Question 19

What classification is given to the following molecule?

Accepted Answer

A)  a prostaglandin G derivative
B)  a prostaglandin E derivative
C)  a leukotriene
D)  a thromboxane
E)  none of the above

Question 20

Which of the following explains why the bile acids are much better suited than cholesterol for use as emulsification agents for fats?

Accepted Answer

A)  cholesterol is oxidized to form the more polar molecule 7-hydroxycholesterol in route to formation of the bile acids
B)  while cholesterol contains a hydroxyl group as its sole hydrophilic functionality,cholic acid contains 3 hydroxyl groups and a carboxylic acid
C)  cholate is conjugated with glycine to make glycocholate
D)  cholate is conjugated with taurine to make taurocholate
E)  all of the above

Exam 19: Lipid Metabolism Ii: Membrane Lipids, steroids, isoprenoids, and Eicosanoids

The synthesis of the glycosphingolipids begins with the reaction of either UDP-glucose or UDP-galactose with _____________.

Correct AnswerverifiedShow Answer

Tay-Sachs disease is caused by a deficiency of __________ which results in an accumulation of ___________.

Correct AnswerverifiedD

Show the reaction catalyzed by 3-hydroxy-3-methylglutrayl-CoA reductase.

Correct AnswerverifiedShow Answer

Which of the following phospholipids is produced in eukaryotes but not prokaryotes?

Correct AnswerverifiedD

7-dehydrocholesterol reacts with _________ to produce cholecalciferol (vitamin D3)

Correct AnswerverifiedShow Answer

Which of the following is used to activate phosphatidic acid for conversion to various phospholipids?

Correct AnswerverifiedShow Answer

Show the products of the following reaction and name them:

Correct AnswerverifiedShow Answer

The synthesis of 1 molecule of cholesterol requires _____ molecules of isopentenyl pyrophosphate,with each molecule of isopentenyl pyrophosphate requiring _____ molecules of acetyl-CoA.

Correct AnswerverifiedShow Answer

Phospholipids are synthesized in the ___________,then transferred to the ____________ via transport vesicles.

Correct AnswerverifiedShow Answer

How is the activity of HMG-CoA reductase reduced?

Correct AnswerverifiedShow Answer

Which of the following correctly identifies the order of carbocations found in the mechanism of squalene synthase?

Correct AnswerverifiedShow Answer

Squalene epoxidase is an example of a mixed function oxidase,meaning that it uses both _______ and _______ as substrates.

Correct AnswerverifiedShow Answer

Which of the following forms of vitamin A is covalently attached to a lysine residue of the protein opsin to form the complex called rhodopsin?

Correct AnswerverifiedShow Answer

In prokaryotes,_________ is used exclusively as the precursor for phosphatidic acid while in eukaryotes,_________is one of three possible precursors.

Correct AnswerverifiedShow Answer

What is the term for the molecule shown below?

Correct AnswerverifiedE

Which of the following is accomplished in one enzyme catalyzed reaction?

Correct AnswerverifiedShow Answer

In eukaryotes,the conversion of DHAP to 1-acylglycerol-3-phosphate is a two-step process.Show the reactants and products missing in the following scheme.

Correct AnswerverifiedShow Answer

Which of the following is the regulatory step in cholesterol synthesis?

Correct AnswerverifiedShow Answer

What classification is given to the following molecule?

Correct AnswerverifiedShow Answer

Which of the following explains why the bile acids are much better suited than cholesterol for use as emulsification agents for fats?

Correct AnswerverifiedShow Answer

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Tay-Sachs disease is caused by a deficiency of which results in an accumulation of _.

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D

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D

7-dehydrocholesterol reacts with _________ to produce cholecalciferol (vitamin D₃)

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The synthesis of 1 molecule of cholesterol requires _ molecules of isopentenyl pyrophosphate,with each molecule of isopentenyl pyrophosphate requiring _ molecules of acetyl-CoA.

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Phospholipids are synthesized in the _,then transferred to the __ via transport vesicles.

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Squalene epoxidase is an example of a mixed function oxidase,meaning that it uses both _ and _ as substrates.

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In prokaryotes,_ is used exclusively as the precursor for phosphatidic acid while in eukaryotes,_is one of three possible precursors.

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E

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