Question 1

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

Accepted Answer

Tay-Sachs disease is caused by a deficiency of lysosomal N-acetylhexosaminidase A, which leads to an accumulation of GM2 ganglioside in the brain and other tissues.

Question 2

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

Accepted Answer

CTP is used to activate phosphatidic acid for conversion to various phospholipids, facilitating the synthesis of phosphatidylcholine and phosphatidylethanolamine through the Kennedy pathway.

Question 3

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

Accepted Answer

In prokaryotes, diacylglycerol is used exclusively as the precursor for phosphatidic acid while in eukaryotes, glycerol-3-phosphate is one of three possible precursors.

Question 4

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

The answer of The synthesis of 1 molecule of cholesterol...

Question 5

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

Accepted Answer

HMG-CoA reductase is the regulatory step in cholesterol synthesis as it converts HMG-CoA to mevalonate, which is a precursor for cholesterol synthesis. The activity of this enzyme is tightly regulated by feedback inhibition, transcriptional control, and post-translational modification.

Question 6

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

Accepted Answer

7-dehydrocholesterol in the skin reacts with UV light to produce cholecalciferol (vitamin D).

Question 7

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

Accepted Answer

Methionine is critical for choline and phosphatidylcholine synthesis as it is a precursor for S-adenosylmethionine (SAM), which donates a methyl group to phosphatidylethanolamine to form phosphatidylcholine.

Question 8

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

11-cis-retinal is the form of vitamin A that is covalently attached to a lysine residue of the protein opsin to form the complex called rhodopsin.

Question 9

What is the term for the molecule shown below?

Accepted Answer

The answer of What is the term for the molecule...

Question 10

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

Accepted Answer

The conversion of androstenedione to testosterone is accomplished in one enzyme-catalyzed reaction, specifically by the enzyme 17β-hydroxysteroid dehydrogenase.

Question 11

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

PGH synthase contains two different functionalities, a cyclooxygenase that uses two molecules of oxygen as substrates and a peroxidase which performs a 2-electron reduction.

Question 12

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

Question 13

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

Accepted Answer

Phosphatidylinositol is a phospholipid that is specifically produced in eukaryotic cells and plays a key role in cell signaling and membrane structure. Prokaryotes do not synthesize phosphatidylinositol.

Question 14

The biosynthesis of cardiolipin involves the reaction of phosphatidylglycerol with a molecule of ___________.

Accepted Answer

Cardiolipin biosynthesis involves the reaction of phosphatidylglycerol with another molecule of phosphatidylglycerol, leading to the formation of cardiolipin and a molecule of glycerol.

Question 15

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

Accepted Answer

The answer of The synthesis of phosphatidylethanolamine in prokaryotes involves...

Question 16

How is the activity of HMG-CoA reductase reduced?

Accepted Answer

HMG-CoA reductase activity is reduced through ubiquitination in response to sterol accumulation, which targets the enzyme for proteolysis. This is a key regulatory mechanism to control cholesterol synthesis in cells.

Question 17

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

Accepted Answer

The synthesis of glycosphingolipids begins with the reaction of UDP-glucose or UDP-galactose with ceramide to form glucosylceramide or galactosylceramide, respectively.

Question 18

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

Accepted Answer

Squalene epoxidase is involved in the production of cholesterol and uses both squalene and NADPH as substrates. Therefore, E is the correct choice.

Question 19

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

Accepted Answer

The answer of Which of the following correctly identifies the...

Question 20

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

Accepted Answer

Phospholipids are synthesized in the smooth endoplasmic reticulum and then transported to the Golgi complex via transport vesicles. Therefore, option A is the correct answer.

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

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

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

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

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

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

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

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

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?

What is the term for the molecule shown below?

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

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

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

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

The biosynthesis of cardiolipin involves the reaction of phosphatidylglycerol with a molecule of ___________.

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

How is the activity of HMG-CoA reductase reduced?

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

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

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

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

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

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

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

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

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

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

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

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

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?

What is the term for the molecule shown below?

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

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

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

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

The biosynthesis of cardiolipin involves the reaction of phosphatidylglycerol with a molecule of ___________.

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

How is the activity of HMG-CoA reductase reduced?

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

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

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

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

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

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

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

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

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

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

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

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