Question 1

What is phosphatidylcholine? How is it synthesized in mammals?

Accepted Answer

Phosphatidylcholine is one of the most common phospholipids in mammals. The choline can be scavenged from the diet, activated to CDP-choline and used to form the molecule. It can also be synthesized in the liver by methylation of phosphatidyl ethanolamine using
S-adenosylmethionine.

Question 2

Which of the following combines with glycine to form a major bile salt?

Accepted Answer

A)  phosphatidate 
B)  phosphatidylethanolamine 
C)  glycerol 
D)  cholesterol 
E)  phosphatidylserine 
A)  phosphatidate 
B)  phosphatidylethanolamine 
C)  glycerol 
D)  cholesterol 
E)  phosphatidylserine D

Question 3

In mammalian cells, phosphatidate is synthesized in the outer mitochondrial membrane and the ____________________________.

Accepted Answer

endoplasmic reticulum or ER

Question 4

The starting materials necessary to synthesize sphingosine are

Accepted Answer

A)  palmitoyl CoA and serine. 
B)  acetyl CoA and glycine. 
C)  palmitoyl CoA and aspartate. 
D)  acetyl CoA and glutamine. 
E)  None of the answers is correct. 
A)  palmitoyl CoA and serine. 
B)  acetyl CoA and glycine. 
C)  palmitoyl CoA and aspartate. 
D)  acetyl CoA and glutamine. 
E)  None of the answers is correct.

Question 5

How is methionine metabolism related to the synthesis of phosphatidyl choline?

Accepted Answer

One way the phosphatidyl choline can be

Question 6

How are gangliosides synthesized?

Accepted Answer

These structures have oligosaccharides a

Question 7

What is the role of CTP in the synthesis of a phospholipid?

Accepted Answer

In the de novo synthesis, the CTP is use

Question 8

What are bile salts?

Accepted Answer

Bile salts are amphiphilic derivatives o

Question 9

Which derivative of cholesterol is the precursor of the steroid hormones?

Accepted Answer

A)  aldosterone 
B)  progesterone 
C)  cortisol 
D)  androstenedione 
E)  pregnenolone 
A)  aldosterone 
B)  progesterone 
C)  cortisol 
D)  androstenedione 
E)  pregnenolone

Question 10

Which of the following is the common precursor for both the phosphatidyl inositols and triacylglycerols?

Accepted Answer

A)  cardiolipin 
B)  inosinic acid 
C)  phosphatidate 
D)  CDP-diacylglycerol 
E)  None of the answers is correct. 
A)  cardiolipin 
B)  inosinic acid 
C)  phosphatidate 
D)  CDP-diacylglycerol 
E)  None of the answers is correct.

Question 11

What is the primary bile salt?

Accepted Answer

A)  aldosterone 
B)  pregnenolone 
C)  cortisol 
D)  glycocholate 
E)  taurocholate 
A)  aldosterone 
B)  pregnenolone 
C)  cortisol 
D)  glycocholate 
E)  taurocholate

Question 12

The synthesis of ____________________ is the committed step in cholesterol biosynthesis.

Accepted Answer

The answer of The synthesis of ____________________ is the committed...

Question 13

What membrane component is produced by a base-exchange reaction with phosphatidylethanolamine?

Accepted Answer

A)  phosphatidylcholine 
B)  phosphatidylserine 
C)  phosphatidylinositol 
D)  phosphatidic acid 
E)  None of the answers is correct. 
A)  phosphatidylcholine 
B)  phosphatidylserine 
C)  phosphatidylinositol 
D)  phosphatidic acid 
E)  None of the answers is correct.

Question 14

Phosphatidate is formed from

Accepted Answer

A)  glycerol 3-phosphate and two fatty acyl CoA's. 
B)  glycerol and two free fatty acids. 
C)  pyruvate and triacylglycerol. 
D)  glycerol and two fatty acyl CoA's. 
E)  glycerol 3-phosphate and diacylglycerol. 
A)  glycerol 3-phosphate and two fatty acyl CoA's. 
B)  glycerol and two free fatty acids. 
C)  pyruvate and triacylglycerol. 
D)  glycerol and two fatty acyl CoA's. 
E)  glycerol 3-phosphate and diacylglycerol.

Question 15

Describe cholesterol synthesis in three major steps.

Accepted Answer

The stages are: 1) the synthes

Question 16

Which of the following is the major component of low-density lipoproteins?

Accepted Answer

A)  sphingomyelin 
B)  free cholesterol 
C)  triacylglycerol 
D)  cholesteryl linoleate 
E)  apo B-100 
A)  sphingomyelin 
B)  free cholesterol 
C)  triacylglycerol 
D)  cholesteryl linoleate 
E)  apo B-100

Question 17

______________________ is the major carrier of cholesterol esters in the blood.

Accepted Answer

Low-densit

Question 18

The role of lipoprotein particles is to

Accepted Answer

A)  solubilize hydrophobic lipids. 
B)  aid in clot formation. 
C)  transport insoluble proteins. 
D)  transport free fatty acids. 
E)  None of the answers is correct. 
A)  solubilize hydrophobic lipids. 
B)  aid in clot formation. 
C)  transport insoluble proteins. 
D)  transport free fatty acids. 
E)  None of the answers is correct.

Question 19

Which of the following metabolites is the source of all carbons for cholesterol?

Accepted Answer

A)  glucose 
B)  pyruvate 
C)  succinyl CoA 
D)  oxaloacetate 
E)  acetyl CoA 
A)  glucose 
B)  pyruvate 
C)  succinyl CoA 
D)  oxaloacetate 
E)  acetyl CoA

Question 20

In the biosynthesis of phosphatidates, the fatty acyl group attached to the C-2 position is usually ______________________.

Accepted Answer

The answer of In the biosynthesis of phosphatidates, the fatty...

Exam 26: Biosynthesis of Membrane Lipids and Steroids

What is phosphatidylcholine? How is it synthesized in mammals?

Which of the following combines with glycine to form a major bile salt?

In mammalian cells, phosphatidate is synthesized in the outer mitochondrial membrane and the ____________________________.

The starting materials necessary to synthesize sphingosine are

How is methionine metabolism related to the synthesis of phosphatidyl choline?

How are gangliosides synthesized?

What is the role of CTP in the synthesis of a phospholipid?

What are bile salts?

Which derivative of cholesterol is the precursor of the steroid hormones?

Which of the following is the common precursor for both the phosphatidyl inositols and triacylglycerols?

What is the primary bile salt?

The synthesis of ____________________ is the committed step in cholesterol biosynthesis.

What membrane component is produced by a base-exchange reaction with phosphatidylethanolamine?

Phosphatidate is formed from

Describe cholesterol synthesis in three major steps.

Which of the following is the major component of low-density lipoproteins?

______________________ is the major carrier of cholesterol esters in the blood.

The role of lipoprotein particles is to

Which of the following metabolites is the source of all carbons for cholesterol?

In the biosynthesis of phosphatidates, the fatty acyl group attached to the C-2 position is usually ______________________.

Biochemistry: an Evolving Science

Protein Composition and Structure

Exploring Proteins and Proteomes

DNA, RNA, and the Flow of Genetic Information

Exploring Genes and Genomes

Exploring Evolution and Bioinformatics

Hemoglobin: a Portrait of a Protein in Action

Enzymes: Basic Concepts and Kinetics

Oxidative Phosphorylation

Catalytic Strategies

Regulatory Strategies

Carbohydrates

Lipids and Cell Membranes

Membrane Channels and Pumps

Signal-Transduction Pathways

Metabolism: Basic Concepts and Design

Glycolysis and Gluconeogenesis

The Citric Acid Cycle

The Light Reactions of Photosynthesis

The Calvin Cycle and the Pentose Phosphate Pathway

Glycogen Metabolism

Fatty Acid Metabolism

Protein Turnover and Amino Acid Catabolism

The Biosynthesis of Amino Acids

Nucleotide Biosynthesis

The Integration of Metabolism

DNA Replication, Repair, and Recombination

Rna Synthesis and Processing

Protein Synthesis

The Control of Gene Expression in Prokaryotes

The Control of Gene Expression in Eukaryotes

Sensory Systems

The Immune System

Molecular Motors

Drug Development

Filters