Question 1

In membrane lipid biosynthesis,the nucleotide ________________ is used to activate the components of the reaction.

Accepted Answer

CTP

Question 2

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. C

Question 3

Describe cholesterol synthesis in three major steps.

Accepted Answer

The stages are: 1)the synthesis of the isoprene units (isopentyl pyrophosphate),2)condensation of six units to form squalene,and 3)cyclization of the squalene.

Question 4

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 5

The major carrier(s)of dietary fat from the intestine is (are)

Accepted Answer

A)  VLDL. 
B)  chylomicrons. 
C)  HDL. 
D)  LDL. 
E)  IDL. 
A)  VLDL. 
B)  chylomicrons. 
C)  HDL. 
D)  LDL. 
E)  IDL.

Question 6

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 7

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

Accepted Answer

One way the phosphatidyl choline can be

Question 8

What is the major site of triacylglycerol synthesis in mammals?

Accepted Answer

A)  liver 
B)  adipose tissue 
C)  small intestine 
D)  kidney 
E)  pancreas 
A)  liver 
B)  adipose tissue 
C)  small intestine 
D)  kidney 
E)  pancreas

Question 9

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 10

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 11

What are the steps in LDL uptake into cells?

Accepted Answer

The LDL contains apolipoprotein B-100,wh

Question 12

Hydroxylation of cholesterol by cytochrome P450 requires

Accepted Answer

A)  NADPH. 
B)  O2 
C)  PLP. 
D)  thiamine. 
E)  NADPH and O2. 
A)  NADPH. 
B)  O2 
C)  PLP. 
D)  thiamine. 
E)  NADPH and O2.

Question 13

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 14

The highest concentration of sphingolipids is found in the

Accepted Answer

A)  central nervous system. 
B)  lymph system. 
C)  serum. 
D)  adipose tissue. 
E)  None of the answers is correct. 
A)  central nervous system. 
B)  lymph system. 
C)  serum. 
D)  adipose tissue. 
E)  None of the answers is correct.

Question 15

The energy for the conversion of provitamin D3 to vitamin D3 comes from

Accepted Answer

A)  ATP hydrolysis. 
B)  NADPH oxidation. 
C)  thioester hydrolysis. 
D)  ultraviolet light from the Sun. 
E)  visible light from the Sun. 
A)  ATP hydrolysis. 
B)  NADPH oxidation. 
C)  thioester hydrolysis. 
D)  ultraviolet light from the Sun. 
E)  visible light from the Sun.

Question 16

How are gangliosides synthesized?

Accepted Answer

These structures have oligosaccharides a

Question 17

In phosphatidyl inositol,__________ and _________ usually occupy the C-1 position and the C-2 position,respectively.

Accepted Answer

A)  stearic acid; cholesterol 
B)  stearic acid; arachidonic acid 
C)  palmitolyl acid; arachidonic acid 
D)  oleic acid; arachidonic acid 
E)  None of the answers is correct. 
A)  stearic acid; cholesterol 
B)  stearic acid; arachidonic acid 
C)  palmitolyl acid; arachidonic acid 
D)  oleic acid; arachidonic acid 
E)  None of the answers is correct.

Question 18

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

Accepted Answer

In the de novo synthesis,the CTP is used

Question 19

Which of the following is the immediate product of HMG-CoA reductase in the cholesterol synthesis pathway?

Accepted Answer

A)  isopentenyl pyrophosphate 
B)  mevalonate 
C)  squalene 
D)  farnesyl pyrophosphate 
E)  acetoacetyl CoA 
A)  isopentenyl pyrophosphate 
B)  mevalonate 
C)  squalene 
D)  farnesyl pyrophosphate 
E)  acetoacetyl CoA

Question 20

How do blood levels of lipoproteins serve diagnostic purposes?

Accepted Answer

The ratio of LDL to HDL is important.Too

Exam 26: Biosynthesis of Membrane Lipids and Steroids

In membrane lipid biosynthesis,the nucleotide ________________ is used to activate the components of the reaction.

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

Describe cholesterol synthesis in three major steps.

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

The major carrier(s)of dietary fat from the intestine is (are)

What is the primary bile salt?

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

What is the major site of triacylglycerol synthesis in mammals?

Phosphatidate is formed from

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

What are the steps in LDL uptake into cells?

Hydroxylation of cholesterol by cytochrome P450 requires

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

The highest concentration of sphingolipids is found in the

The energy for the conversion of provitamin D3 to vitamin D3 comes from

How are gangliosides synthesized?

In phosphatidyl inositol,__________ and _________ usually occupy the C-1 position and the C-2 position,respectively.

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

Which of the following is the immediate product of HMG-CoA reductase in the cholesterol synthesis pathway?

How do blood levels of lipoproteins serve diagnostic purposes?

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

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

Oxidative Phosphorylation

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

The energy for the conversion of provitamin D₃ to vitamin D₃ comes from

In phosphatidyl inositol,__ and _ usually occupy the C-1 position and the C-2 position,respectively.