Question 1

Compared to b-oxidation,fatty acid synthesis requires this extra vitamin or cofactor.

Accepted Answer

A)  Biotin 
B)  Riboflavin 
C)  Niacin 
D)  Pantothenic acid 
E)  All of these are used in both pathways. 
A)  Biotin 
B)  Riboflavin 
C)  Niacin 
D)  Pantothenic acid 
E)  All of these are used in both pathways. A

Question 2

Which of the following reactants is involved in both fatty acids synthesis and breakdown?

Accepted Answer

A)  CO2. 
B)  Malonyl-CoA 
C)  NADPH. 
D)  Pantothenic acid. 
E)  All of these reactants are involved in both fatty acid synthesis and breakdown. 
A)  CO2. 
B)  Malonyl-CoA 
C)  NADPH. 
D)  Pantothenic acid. 
E)  All of these reactants are involved in both fatty acid synthesis and breakdown. D

Question 3

The enzyme activity catalyzing the reaction shown is best termed a

Accepted Answer

A)  reductase 
B)  hydratase 
C)  dehydratase 
D)  dehydrogenase 
A)  reductase 
B)  hydratase 
C)  dehydratase 
D)  dehydrogenase D

Question 4

Isoprenoid derivatives play what role in steroid biosynthesis?

Accepted Answer

A)  inhibit a key step 
B)  are key intermediates 
C)  compete with steroid biosynthesis for a limited precursor 
D)  its role is unknown 
A)  inhibit a key step 
B)  are key intermediates 
C)  compete with steroid biosynthesis for a limited precursor 
D)  its role is unknown

Question 5

The conversion of methylmalonyl-CoA to succinyl-CoA involves which of these cofactors?

Accepted Answer

A)  thiamine pyrophosphate 
B)  Vitamin B12 
C)  NAD 
D)  biotin 
A)  thiamine pyrophosphate 
B)  Vitamin B12 
C)  NAD 
D)  biotin

Question 6

Acetyl-CoA carboxylase uses which of these cofactors?

Accepted Answer

A)  thiamine pyrophosphate 
B)  Vitamin B12 
C)  NAD 
D)  biotin 
A)  thiamine pyrophosphate 
B)  Vitamin B12 
C)  NAD 
D)  biotin

Question 7

Which of the following is not true regarding catabolism of triacylglycerols?

Accepted Answer

A)  Control of release of fatty acids from triacylglycerols in adipocytes involves cyclic AMP as a second messenger. 
B)  When cAMP is a second messenger in the catabolsim of triacylglycerols, it activates a protein kinase 
C)  The protein kinase, once activated, cleaves fatty acids from the triacylglycerol 
D)  The phosphorylated form of triacylglycerol lipase is the active form 
E)  All of these are true 
A)  Control of release of fatty acids from triacylglycerols in adipocytes involves cyclic AMP as a second messenger. 
B)  When cAMP is a second messenger in the catabolsim of triacylglycerols, it activates a protein kinase 
C)  The protein kinase, once activated, cleaves fatty acids from the triacylglycerol 
D)  The phosphorylated form of triacylglycerol lipase is the active form 
E)  All of these are true

Question 8

Which of the following is not a function of cholesterol in the human body?

Accepted Answer

A)  Precursor of steroid hormones. 
B)  Energy storage compound. 
C)  Precursor of bile salts. 
D)  Component of cell membranes. 
E)  All of these are important function of cholesterol in humans. 
A)  Precursor of steroid hormones. 
B)  Energy storage compound. 
C)  Precursor of bile salts. 
D)  Component of cell membranes. 
E)  All of these are important function of cholesterol in humans.

Question 9

The committed step in cholesterol biosynthesis is catalyzed by

Accepted Answer

A)  HMG-CoA synthase 
B)  HMG-CoA reductase 
C)  mevalonate kinase 
D)  squalene monooxygenase 
A)  HMG-CoA synthase 
B)  HMG-CoA reductase 
C)  mevalonate kinase 
D)  squalene monooxygenase

Question 10

What effect do high concentrations of ketone bodies have on blood pH?

Accepted Answer

A)  They tend to lower blood pH. 
B)  They tend to increase blood pH. 
C)  They have no effect on blood pH. 
A)  They tend to lower blood pH. 
B)  They tend to increase blood pH. 
C)  They have no effect on blood pH.

Question 11

Palmitic acid,with 16 carbons,requires 8 cycles of b-oxidation to produce 8 acetyl-CoA.

Accepted Answer

A) True 
 B)False

Question 12

During fatty acid synthesis,the growing fatty acid is always bound to a protein.

Accepted Answer

A) True 
 B)False

Question 13

How is acetyl-CoA transported from the mitochondria to the cytosol for fatty acid synthesis?

Accepted Answer

A)  directly as acetyl-CoA 
B)  through a temporary linkage to carnitine 
C)  as citric acid 
D)  There is no reason to transport acetyl-CoA from the mitochondria to the cytosol, since it is produced primarily in the cytosol. 
A)  directly as acetyl-CoA 
B)  through a temporary linkage to carnitine 
C)  as citric acid 
D)  There is no reason to transport acetyl-CoA from the mitochondria to the cytosol, since it is produced primarily in the cytosol.

Question 14

Which of the following mechanisms explains why fatty acid synthesis and breakdown do not compete with each other in the body?

Accepted Answer

A)  Synthesis and breakdown take place in two separate compartments of the cell. 
B)  One process uses NADH/NAD+ and the other uses NADPH/NADP+. 
C)  They are not attached to the same carrier molecule in the two processes. 
D)  All of these mechanisms are in operation. 
A)  Synthesis and breakdown take place in two separate compartments of the cell. 
B)  One process uses NADH/NAD+ and the other uses NADPH/NADP+. 
C)  They are not attached to the same carrier molecule in the two processes. 
D)  All of these mechanisms are in operation.

Question 15

Synthesis of fatty acids involves simple reversal of the b-oxidation cycle.

Accepted Answer

A) True 
 B)False

Question 16

Since acetyl-CoA carboxylase is key to the synthesis of fatty acids,inhibitors of this enzyme may be useful for weight loss or treatment of obesity.

Accepted Answer

A) True 
 B)False

Question 17

Which of the following is not a product of the activation of fatty acids?

Accepted Answer

A)  A thioester 
B)  ADP 
C)  Pyrophosphate 
D)  Phosphate 
E)  All of these are products of the activation of a fatty acid. 
A)  A thioester 
B)  ADP 
C)  Pyrophosphate 
D)  Phosphate 
E)  All of these are products of the activation of a fatty acid.

Question 18

Which of the following is not true?

Accepted Answer

A)  One advantage of the b-oxidation of fats compared to oxidation of sugars is that fatty acids produce more metabolic water. 
B)  The oxidation of fats produces more energy per carbon than the oxidation of carbohydrates 
C)  Fat yields more energy than carbohydrates because it is more oxidized 
D)  For every cycle of oxidation of a fatty acid, one NADH and one FADH2 are produced 
A)  One advantage of the b-oxidation of fats compared to oxidation of sugars is that fatty acids produce more metabolic water. 
B)  The oxidation of fats produces more energy per carbon than the oxidation of carbohydrates 
C)  Fat yields more energy than carbohydrates because it is more oxidized 
D)  For every cycle of oxidation of a fatty acid, one NADH and one FADH2 are produced

Question 19

A key intermediate in the formation of "ketone bodies" is

Accepted Answer

A)  succinyl-CoA 
B)  methyl malonyl-CoA 
C)  propionyl-CoA 
D)  acetoacetyl-CoA 
A)  succinyl-CoA 
B)  methyl malonyl-CoA 
C)  propionyl-CoA 
D)  acetoacetyl-CoA

Question 20

The b-oxidation of fatty acids with an odd number of carbons requires additional enzymes to allow all the products to enter the citric acid cycle .

Accepted Answer

A) True 
 B)False

Exam 21: Lipid Metabolism

Compared to b-oxidation,fatty acid synthesis requires this extra vitamin or cofactor.

Which of the following reactants is involved in both fatty acids synthesis and breakdown?

The enzyme activity catalyzing the reaction shown is best termed a

Isoprenoid derivatives play what role in steroid biosynthesis?

The conversion of methylmalonyl-CoA to succinyl-CoA involves which of these cofactors?

Acetyl-CoA carboxylase uses which of these cofactors?

Which of the following is not true regarding catabolism of triacylglycerols?

Which of the following is not a function of cholesterol in the human body?

The committed step in cholesterol biosynthesis is catalyzed by

What effect do high concentrations of ketone bodies have on blood pH?

Palmitic acid,with 16 carbons,requires 8 cycles of b-oxidation to produce 8 acetyl-CoA.

During fatty acid synthesis,the growing fatty acid is always bound to a protein.

How is acetyl-CoA transported from the mitochondria to the cytosol for fatty acid synthesis?

Which of the following mechanisms explains why fatty acid synthesis and breakdown do not compete with each other in the body?

Synthesis of fatty acids involves simple reversal of the b-oxidation cycle.

Since acetyl-CoA carboxylase is key to the synthesis of fatty acids,inhibitors of this enzyme may be useful for weight loss or treatment of obesity.

Which of the following is not a product of the activation of fatty acids?

Which of the following is not true?

A key intermediate in the formation of "ketone bodies" is

The b-oxidation of fatty acids with an odd number of carbons requires additional enzymes to allow all the products to enter the citric acid cycle .

Biochemistry and the Organization of Cells

Water: The Solvent for Biochemical Reactions

Amino Acids and Peptides

The Three-Dimensional Structure of Proteins

Protein Purification and Characterization Techniques

The Behavior of Proteins: Enzymes

The Behavior of Proteins: Enzymes, Mechanisms, and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids: How Structure Conveys Information

Biosynthesis of Nucleic Acids: Replication

Transcription of the Genetic Code: Biosynthesis of Rna

Protein Synthesis: Translation of the Genetic Message

Nucleic Acid Biotechnology Techniques

Viruses, Cancer, and Immunology

The Importance of Energy Changes and Electron Transfer in Metabolism

Carbohydrates

Glycolysis

Storage Mechanisms and Control in Carbohydrate Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism: Cellular Signaling

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