Question 1

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 2

The synthesis of which of the following molecules would be inhibited by aspirin?

Accepted Answer

A)  prostaglandin F2 α\alphaα 
B)  prostaglandin D2
C)  prostaglandin E2
D)  prostaglandin H2
E)  all of the above

Question 3

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...

Question 4

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 5

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

Question 6

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 B

Question 7

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 8

The enzyme PGH synthase contains two different functionalities, a __________ that uses two molecules of oxygen as substrates and __________ which performs a 2 electron reduction.

Accepted Answer

A)  cyclooxygenase; peroxidase
B)  cyclooxygenase; reductase
C)  dioxygenase; peroxidase
D)  dioxygenase; reductase
E)  lipoxygenase; peroxidase A

Question 9

Which of the following amino acids is critical for choline and phosphatidylcholine synthesis?

Accepted Answer

A)  serine
B)   β\betaβ -alanine
C)  homocysteine
D)  methionine
E)  homoserine

Question 10

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

Question 11

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 12

Show the products of the following reaction and name them:

Accepted Answer

<img  loading="lazy" src="/assets/images/blured-textbook.svg" class="d-inline m-1" alt="blured image" width="139" height="30"> phosphati...

Question 13

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 A

Question 14

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

Question 15

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 16

The synthesis of phosphatidylethanolamine in prokaryotes involves _________________ while in mammals _______________ occurs.

Accepted Answer

A)  reaction of CDP-diacylglycerol with ethanolamine; decarboxylation of phosphatidylserine
B)  decarboxylation of phosphatidylserine; reaction of CDP-ethanolamine with diacylglycerol
C)  reaction of phosphoethanolamine with diacylglycerol; reaction of CDP-ethanolamine with diacylglycerol
D)  decarboxylation of phosphatidylserine; reaction of CDP-diacylglycerol with ethanolamine
E)  reaction of CDP-diacylglycerol with ethanolamine; reaction of phosphoethanolamine with diacylglycerol

Question 17

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 18

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 19

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

Question 20

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

Exam 19: Lipid Metabolism Ii: Membrane Lipids, Steroids, Isoprenoids, and Eicosanoids

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

The synthesis of which of the following molecules would be inhibited by aspirin?

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 used to activate phosphatidic acid for conversion to various phospholipids?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedB

How is the activity of HMG-CoA reductase reduced?

Correct AnswerverifiedShow Answer

The enzyme PGH synthase contains two different functionalities, a __________ that uses two molecules of oxygen as substrates and __________ which performs a 2 electron reduction.

Correct AnswerverifiedA

Which of the following amino acids is critical for choline and phosphatidylcholine synthesis?

Correct AnswerverifiedShow Answer

What is the term for the molecule shown below?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Show the products of the following reaction and name them:

Correct Answerverified phosphati...View AnswerShow Answer

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

Correct AnswerverifiedA

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

What classification is given to the following molecule?

Correct AnswerverifiedShow Answer

The synthesis of phosphatidylethanolamine in prokaryotes involves _________________ while in mammals _______________ occurs.

Correct AnswerverifiedShow Answer

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

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

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

Correct AnswerverifiedShow Answer

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

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

Correct Answer
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B

Correct Answer
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The enzyme PGH synthase contains two different functionalities, a that uses two molecules of oxygen as substrates and which performs a 2 electron reduction.

Correct Answer
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A

Correct Answer
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phosphati...
View Answer

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

Correct Answer
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A

Correct Answer
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Correct Answer
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The synthesis of phosphatidylethanolamine in prokaryotes involves ___ while in mammals _ occurs.

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

Correct Answer
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Correct Answer
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