Question 1

The cyclization reaction that produces lanosterol in the course of steroid biosynthesis is remarkable because

Accepted Answer

A)  it involves large molecules 
B)  it involves methyl groups 
C)  of the extreme conditions under which it takes place 
D)  it is a concerted reaction 
A)  it involves large molecules 
B)  it involves methyl groups 
C)  of the extreme conditions under which it takes place 
D)  it is a concerted reaction

Question 2

Which of the following statements concerning the anabolism and catabolism of fatty acids is true?

Accepted Answer

A)  Biotin is required for oxidation of fatty acids but not for anabolism. 
B)  NADPH is required for anabolism of fatty acids and not for catabolism. 
C)  Anabolism occurs in the intermembrane space of mitochondria while catabolism takes place in the mitochondrial matrix. 
D)  Acetyl-CoA is not required for anabolism. 
A)  Biotin is required for oxidation of fatty acids but not for anabolism. 
B)  NADPH is required for anabolism of fatty acids and not for catabolism. 
C)  Anabolism occurs in the intermembrane space of mitochondria while catabolism takes place in the mitochondrial matrix. 
D)  Acetyl-CoA is not required for anabolism.

Question 3

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 4

The metabolically activated form of a fatty acid is

Accepted Answer

A)  an ester 
B)  a Schiff base 
C)  a phosphate ester 
D)  a thioester 
E)  none of these 
A)  an ester 
B)  a Schiff base 
C)  a phosphate ester 
D)  a thioester 
E)  none of these

Question 5

Which of the following is not true?

Accepted Answer

A)  One advantage of the β-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 β-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 6

Phospholipases break down fats by

Accepted Answer

A)  adding a phosphate group to them. 
B)  reducing the double bonds to single bonds. 
C)  hydrolyzing them. 
D)  removing acetyl-CoA units. 
E)  none of these 
A)  adding a phosphate group to them. 
B)  reducing the double bonds to single bonds. 
C)  hydrolyzing them. 
D)  removing acetyl-CoA units. 
E)  none of these

Question 7

Which of the following is not true regarding ketone bodies?

Accepted Answer

A)  Ketone bodies form during the catabolism of fats. 
B)  Ketone bodies are an effective means for weight loss, since the body will excrete them in the urine. 
C)  The first enzyme used in the production of ketone bodies is thiolase 
D)  Ketone bodies are always an alternative fuel in all tissues 
A)  Ketone bodies form during the catabolism of fats. 
B)  Ketone bodies are an effective means for weight loss, since the body will excrete them in the urine. 
C)  The first enzyme used in the production of ketone bodies is thiolase 
D)  Ketone bodies are always an alternative fuel in all tissues

Question 8

The use of cyclic AMP to mobilize fatty acids from adipose tissue is analogous to cyclic AMPs role in mobilization of sugars from glycogen in the liver.

Accepted Answer

A) True 
 B)False

Question 9

How many NADPH are oxidized in the synthesis of palmitoyl-CoA from eight molecules of acetyl-CoA?

Accepted Answer

A)  1 
B)  7 
C)  8 
D)  14 
E)  16 
A)  1 
B)  7 
C)  8 
D)  14 
E)  16

Question 10

The unsaturated fatty acids that are intermediates in the β-oxidation cycle have what orientation around the double bond?

Accepted Answer

A)  the cis orientation 
B)  the trans orientation 
C)  can have either orientation 
D)  the orientation is not known 
A)  the cis orientation 
B)  the trans orientation 
C)  can have either orientation 
D)  the orientation is not known

Question 11

Cholesterol can be made in the body; however, some must still be eaten in the diet, since we cannot make enough to meet the demand.

Accepted Answer

A) True 
 B)False

Question 12

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 13

The reactions involved in β-oxidation of fatty acids include the following: 1.
Cleavage of acetyl-CoA from the fatty acid.
2)
Hydration of a double bond.
3)
Formation of a C−C double bond.
4)
Oxidation of an alcohol.
The correct order of these reactions is:

Accepted Answer

A)  1 → 2 → 3 → 4 
B)  4 → 3 → 2 → 1 
C)  3 → 2 → 4 → 1 
D)  2 → 4 → 3 → 1 
E)  1 → 4 → 3 → 2 
A)  1 → 2 → 3 → 4 
B)  4 → 3 → 2 → 1 
C)  3 → 2 → 4 → 1 
D)  2 → 4 → 3 → 1 
E)  1 → 4 → 3 → 2

Question 14

Cholesterol is a precursor of all of the following except

Accepted Answer

A)  cortisone 
B)  testosterone 
C)  progesterone 
D)  lanosterol 
A)  cortisone 
B)  testosterone 
C)  progesterone 
D)  lanosterol

Question 15

The cis double bonds of naturally-occurring fatty acids react well with the hydratase enzyme.

Accepted Answer

A) True 
 B)False

Question 16

If the bicarbonate used in malonyl-CoA synthesis were labeled with 14C in the biosynthesis of palmitate, where would the label be found in the reaction products?

Accepted Answer

A)  CO2 
B)  C−16 of palmitate 
C)  C−1 of palmitate 
D)  evenly distributed in palmitate 
A)  CO2 
B)  C−16 of palmitate 
C)  C−1 of palmitate 
D)  evenly distributed in palmitate

Question 17

Which of the following statements concerning β-oxidation of fatty acids is false?

Accepted Answer

A)  Initiation occurs at the methyl end of the fatty acid. 
B)  β-oxidation is the primary route for degradation of fatty acids. 
C)  β-oxidation takes place in the mitochondrial matrix. 
D)  Two-carbon units are successively eliminated with each round. 
A)  Initiation occurs at the methyl end of the fatty acid. 
B)  β-oxidation is the primary route for degradation of fatty acids. 
C)  β-oxidation takes place in the mitochondrial matrix. 
D)  Two-carbon units are successively eliminated with each round.

Question 18

Of the processes listed below, which is not an important source of acetyl-CoA?

Accepted Answer

A)  pentose phosphate pathway 
B)  amino acid degradation 
C)  glycolysis 
D)  fatty acid oxidation 
A)  pentose phosphate pathway 
B)  amino acid degradation 
C)  glycolysis 
D)  fatty acid oxidation

Question 19

The yield of ATP from oxidation of an unsaturated fatty acid has what relationship to the yield from the oxidation of a saturated fatty acid with the same number of carbon atoms?

Accepted Answer

A)  less 
B)  greater 
C)  the same 
D)  not possible to determine from the information in this chapter 
A)  less 
B)  greater 
C)  the same 
D)  not possible to determine from the information in this chapter

Question 20

The primary function of biotin in metabolism is:

Accepted Answer

A)  to allow for the addition of CO2 to other molecules. 
B)  to inhibit acetyl-CoA carboxylase 
C)  to inhibit carnitine palmitoyltransferase 
D)  all of these 
E)  none of these 
A)  to allow for the addition of CO2 to other molecules. 
B)  to inhibit acetyl-CoA carboxylase 
C)  to inhibit carnitine palmitoyltransferase 
D)  all of these 
E)  none of these

Exam 21: Lipid Metabolism

The cyclization reaction that produces lanosterol in the course of steroid biosynthesis is remarkable because

Which of the following statements concerning the anabolism and catabolism of fatty acids is true?

Acetyl-CoA carboxylase uses which of these cofactors?

The metabolically activated form of a fatty acid is

Which of the following is not true?

Phospholipases break down fats by

Which of the following is not true regarding ketone bodies?

The use of cyclic AMP to mobilize fatty acids from adipose tissue is analogous to cyclic AMPs role in mobilization of sugars from glycogen in the liver.

How many NADPH are oxidized in the synthesis of palmitoyl-CoA from eight molecules of acetyl-CoA?

The unsaturated fatty acids that are intermediates in the β-oxidation cycle have what orientation around the double bond?

Cholesterol can be made in the body; however, some must still be eaten in the diet, since we cannot make enough to meet the demand.

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

The reactions involved in β-oxidation of fatty acids include the following: 1. Cleavage of acetyl-CoA from the fatty acid. 2) Hydration of a double bond. 3) Formation of a C−C double bond. 4) Oxidation of an alcohol. The correct order of these reactions is:

Cholesterol is a precursor of all of the following except

The cis double bonds of naturally-occurring fatty acids react well with the hydratase enzyme.

If the bicarbonate used in malonyl-CoA synthesis were labeled with 14C in the biosynthesis of palmitate, where would the label be found in the reaction products?

Which of the following statements concerning β-oxidation of fatty acids is false?

Of the processes listed below, which is not an important source of acetyl-CoA?

The yield of ATP from oxidation of an unsaturated fatty acid has what relationship to the yield from the oxidation of a saturated fatty acid with the same number of carbon atoms?

The primary function of biotin in metabolism is:

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

Filters

If the bicarbonate used in malonyl-CoA synthesis were labeled with ¹⁴C in the biosynthesis of palmitate, where would the label be found in the reaction products?