Question 1

In the synthesis of phosphatidylcholine from phosphatidylethanolamine, the methyl group donor is:

Accepted Answer

A)  a tetrahydrofolate derivative. 
B)  choline. 
C)  methanol. 
D)  S-adenosylmethionine (adoMet). 
E)  serine. 
A)  a tetrahydrofolate derivative. 
B)  choline. 
C)  methanol. 
D)  S-adenosylmethionine (adoMet). 
E)  serine.

Question 2

Palmitoyl-CoA, , is a direct precursor of:

Accepted Answer

A)  cholesterol. 
B)  malonyl-CoA. 
C)  mevalonate 
D)  sphingosine. 
E)  squalene. 
A)  cholesterol. 
B)  malonyl-CoA. 
C)  mevalonate 
D)  sphingosine. 
E)  squalene.

Question 3

Which compound is NOT an intermediate in transfer of acetyl groups from mitochondria to the cytosol?

Accepted Answer

A)  citrate 
B)  malate 
C)  oxaloacetate 
D)  fumarate 
E)  pyruvate 
A)  citrate 
B)  malate 
C)  oxaloacetate 
D)  fumarate 
E)  pyruvate

Question 4

Which statement is FALSE concerning acetyl-CoA carboxylase?

Accepted Answer

A)  It catalyzes the rate-limiting step in fatty acid synthesis. 
B)  This enzyme is inhibited by palmitate in mammals. 
C)  This enzyme is allosterically activated by citrate in mammals. 
D)  In mammals, this enzyme is inactivated under conditions when glycolysis is active. 
E)  This enzyme is classified as a ligase. 
A)  It catalyzes the rate-limiting step in fatty acid synthesis. 
B)  This enzyme is inhibited by palmitate in mammals. 
C)  This enzyme is allosterically activated by citrate in mammals. 
D)  In mammals, this enzyme is inactivated under conditions when glycolysis is active. 
E)  This enzyme is classified as a ligase.

Question 5

Which protein is NOT typically found in HDL?

Accepted Answer

A)  lecithin cholesterol acyl transferase (LCAT) 
B)  ApoE 
C)  ApoH 
D)  ApoC-I 
E)  ApoD 
A)  lecithin cholesterol acyl transferase (LCAT) 
B)  ApoE 
C)  ApoH 
D)  ApoC-I 
E)  ApoD

Question 6

Which statement is FALSE regarding the conversion of dihydroxyacetone phosphate (DHAP) to glycerol-3-phosphate in the cytosol of adipose cells?

Accepted Answer

A)  The reaction reduces C1 of DHAP. 
B)  This reaction creates a new chiral center. 
C)  This reaction requires the cofactor NADH. 
D)  This reaction is catalyzed by glycerol-3-phosphate dehydrogenase. 
E)  This reaction is catalyzed by an oxidoreductase. 
A)  The reaction reduces C1 of DHAP. 
B)  This reaction creates a new chiral center. 
C)  This reaction requires the cofactor NADH. 
D)  This reaction is catalyzed by glycerol-3-phosphate dehydrogenase. 
E)  This reaction is catalyzed by an oxidoreductase.

Question 7

Describe the mechanism for moving acetyl-CoA produced in the mitochondrial matrix into the cytosol for fatty acid synthesis.

Accepted Answer

Acetyl-CoA is a key metabolic intermedia

Question 8

What statement is FALSE regarding the differences between chylomicrons and VLDL?

Accepted Answer

A)  These two lipoproteins originate in different tissues. 
B)  Chylomicrons have a lower density than VLDL. 
C)  Chylomicrons contain ApoB-48 while VLDL contains ApoB-100. 
D)  Chylomicrons contain a lower percentage of protein compared to VLDL. 
E)  Chylomicrons contain an overall lower triacylglycerol percentage than VLDL. 
A)  These two lipoproteins originate in different tissues. 
B)  Chylomicrons have a lower density than VLDL. 
C)  Chylomicrons contain ApoB-48 while VLDL contains ApoB-100. 
D)  Chylomicrons contain a lower percentage of protein compared to VLDL. 
E)  Chylomicrons contain an overall lower triacylglycerol percentage than VLDL.

Question 9

Conversion of saturated fatty acyl chains to unsaturated fatty acyl chains by fatty acyl-CoA desaturase is accompanied by what other net change?

Accepted Answer

A)  reduction of NAD+ to NADH 
B)  reduction of NADP+ to NADPH 
C)  reduction of O2 to H2O 
D)  reduction of oxaloacetate to malate 
E)  reduction of FAD to FADH2 
A)  reduction of NAD+ to NADH 
B)  reduction of NADP+ to NADPH 
C)  reduction of O2 to H2O 
D)  reduction of oxaloacetate to malate 
E)  reduction of FAD to FADH2

Question 10

Which compound(s) contain(s) the HIGHEST percentage of cholesteryl esters?

Accepted Answer

A)  chylomicrons 
B)  VLDL 
C)  LDL 
D)  HDL 
E)  None of these compounds contain any cholesteryl esters. 
A)  chylomicrons 
B)  VLDL 
C)  LDL 
D)  HDL 
E)  None of these compounds contain any cholesteryl esters.

Question 11

Describe briefly the four stages in the pathway from acetyl-CoA to lanosterol.

Accepted Answer

The four stages in the pathway from acet

Question 12

Which statement is NOT true of the fatty acid synthase and the fatty acid $\beta$-oxidation systems?

Accepted Answer

A)  A derivative of the vitamin pantothenic acid is involved. 
B)  Acyl-CoA derivatives are intermediates. 
C)  Double bonds are oxidized or reduced by pyridine nucleotide coenzymes. 
D)  The processes occur in different cellular compartments. 
E)  The processes occur in the mitochondrial matrix. 
A)  A derivative of the vitamin pantothenic acid is involved. 
B)  Acyl-CoA derivatives are intermediates. 
C)  Double bonds are oxidized or reduced by pyridine nucleotide coenzymes. 
D)  The processes occur in different cellular compartments. 
E)  The processes occur in the mitochondrial matrix.

Question 13

Which apolipoprotein is recognized by the LDL receptor?

Accepted Answer

A)  ApoB-100 
B)  ApoC-I 
C)  ApoC-II 
D)  ApoD 
E)  ApoE 
A)  ApoB-100 
B)  ApoC-I 
C)  ApoC-II 
D)  ApoD 
E)  ApoE

Question 14

Explain the triacylglycerol cycle and how drugs such as rosiglitazone (Avandia) promote this cycle and help lower fatty acid levels in the bloodstream.

Accepted Answer

The triacylglycerol cycle is a metabolic

Question 15

In E. coli the synthesis of phosphatidylethanolamine directly involves:

Accepted Answer

A)  acyl carrier protein. 
B)  biotin. 
C)  CDP-choline. 
D)  phosphatidylglycerol. 
E)  serine. 
A)  acyl carrier protein. 
B)  biotin. 
C)  CDP-choline. 
D)  phosphatidylglycerol. 
E)  serine.

Question 16

Synthesis of a triglyceride from three fatty acids and glycerol costs how many ATP equivalents?

Accepted Answer

A)  three 
B)  four 
C)  five 
D)  six 
E)  seven 
A)  three 
B)  four 
C)  five 
D)  six 
E)  seven

Question 17

What is the "cost" of synthesizing palmitate from acetyl-CoA in the cytosol in terms of high-energy molecules consumed?

Accepted Answer

The synthesis of palmitate (a 16-carbon

Question 18

Which factor does NOT contribute to lowering the risk of atherosclerosis?

Accepted Answer

A)  statin drugs 
B)  HDL 
C)  reverse cholesterol transport 
D)  ApoA-I 
E)  foam cells 
A)  statin drugs 
B)  HDL 
C)  reverse cholesterol transport 
D)  ApoA-I 
E)  foam cells

Question 19

Show the structure of isopentenyl pyrophosphate and of dimethylallyl pyrophosphate. Connect with a dotted line the two carbon atoms that will be joined when these two molecules condense to form the 10-carbon intermediate in cholesterol biosynthesis.

Accepted Answer

Isopentenyl pyrophosphate (IPP) has the

Question 20

Which compound(s) is/are derived from a sterol?

Accepted Answer

A)  bile salts 
B)  gangliosides 
C)  geraniol 
D)  phosphatidylglycerol 
E)  prostaglandins 
A)  bile salts 
B)  gangliosides 
C)  geraniol 
D)  phosphatidylglycerol 
E)  prostaglandins

Exam 21: Lipid Biosynthesis

In the synthesis of phosphatidylcholine from phosphatidylethanolamine, the methyl group donor is:

Palmitoyl-CoA, , is a direct precursor of:

Which compound is NOT an intermediate in transfer of acetyl groups from mitochondria to the cytosol?

Which statement is FALSE concerning acetyl-CoA carboxylase?

Which protein is NOT typically found in HDL?

Which statement is FALSE regarding the conversion of dihydroxyacetone phosphate (DHAP) to glycerol-3-phosphate in the cytosol of adipose cells?

Describe the mechanism for moving acetyl-CoA produced in the mitochondrial matrix into the cytosol for fatty acid synthesis.

What statement is FALSE regarding the differences between chylomicrons and VLDL?

Conversion of saturated fatty acyl chains to unsaturated fatty acyl chains by fatty acyl-CoA desaturase is accompanied by what other net change?

Which compound(s) contain(s) the HIGHEST percentage of cholesteryl esters?

Describe briefly the four stages in the pathway from acetyl-CoA to lanosterol.

Which statement is NOT true of the fatty acid synthase and the fatty acid β\betaβ -oxidation systems?

Which apolipoprotein is recognized by the LDL receptor?

Explain the triacylglycerol cycle and how drugs such as rosiglitazone (Avandia) promote this cycle and help lower fatty acid levels in the bloodstream.

In E. coli the synthesis of phosphatidylethanolamine directly involves:

Synthesis of a triglyceride from three fatty acids and glycerol costs how many ATP equivalents?

What is the "cost" of synthesizing palmitate from acetyl-CoA in the cytosol in terms of high-energy molecules consumed?

Which factor does NOT contribute to lowering the risk of atherosclerosis?

Show the structure of isopentenyl pyrophosphate and of dimethylallyl pyrophosphate. Connect with a dotted line the two carbon atoms that will be joined when these two molecules condense to form the 10-carbon intermediate in cholesterol biosynthesis.

Which compound(s) is/are derived from a sterol?

The Foundations of Biochemistry

Water

Amino Acids, Peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

DNA-Based Information Technologies

Lipids

Biological Membranes and Transport

Biosignaling

Bioenergetics and Biochemical Reaction Types

Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Biosynthesis of Amino Acids, Nucleotides, and Related Molecules

Hormonal Regulation and Integration of Mammalian Metabolism

Genes and Chromosomes

DNA Metabolism

RNA Metabolism

Protein Metabolism

Regulation of Gene Expression

Filters

Which statement is NOT true of the fatty acid synthase and the fatty acid $\beta$ -oxidation systems?