Question 1

Why are triacylglycerols able to provide more energy than carbohydrates (gram for gram)?

Accepted Answer

A) The triacylglycerols have an extremely high group transfer potential. 
B) The carbohydrates are already in a more oxidized state than the triacylglycerols. 
C) The carbohydrates contain fewer carbon-carbon bonds. 
D) The triacylglycerols are less soluble in water than the carbohydrates. 
A) The triacylglycerols have an extremely high group transfer potential. 
B) The carbohydrates are already in a more oxidized state than the triacylglycerols. 
C) The carbohydrates contain fewer carbon-carbon bonds. 
D) The triacylglycerols are less soluble in water than the carbohydrates.

Question 2

Ketone bodies are normally broken down in the liver in preparation for excretion.

Accepted Answer

A) True 
 B)False

Question 3

To prepare for elongation reactions of fatty acid synthesis,the "3-keto" group must be reduced to the ________ form by transfer of electrons (and protons)to the 3-carbon position.

Accepted Answer

A) keto 
B) methylene then hydroxyl 
C) hydroxyl then methylene 
D) all of the above 
A) keto 
B) methylene then hydroxyl 
C) hydroxyl then methylene 
D) all of the above

Question 4

Which of the following is a true statement for fatty acid synthesis?

Accepted Answer

A) It occurs in the mitochondria. 
B) The reducing power for synthesis is supplied by NAD+ and ubiquinone. 
C) Both A and B. 
D) None of the above. 
A) It occurs in the mitochondria. 
B) The reducing power for synthesis is supplied by NAD+ and ubiquinone. 
C) Both A and B. 
D) None of the above.

Question 5

Most of the lipids in the diets of mammals are free fatty acids.

Accepted Answer

A) True 
 B)False

Question 6

The cyclooxygenase-hydroperoxidase pathway is a precursor for each of the following except

Accepted Answer

A) thromboxane A2. 
B) prostacyclin. 
C) prostaglandins. 
D) epinephrine. 
A) thromboxane A2. 
B) prostacyclin. 
C) prostaglandins. 
D) epinephrine.

Question 7

Regulation of acetyl CoA-carboxylase is accomplished by

Accepted Answer

A) inhibition by fatty acyl CoA. 
B) activation by citrate (in vitro). 
C) inactivation by high levels of glucagon. 
D) All of the above. 
A) inhibition by fatty acyl CoA. 
B) activation by citrate (in vitro). 
C) inactivation by high levels of glucagon. 
D) All of the above.

Question 8

Which enzyme requires adenosylcobalamin as a cofactor?

Accepted Answer

A) Carnitine acyl transferase I. 
B) Methylmalonyl-CoA mutase. 
C) Enoyl-CoA hydratase. 
D) Propionyl-CoA carboxylase. 
A) Carnitine acyl transferase I. 
B) Methylmalonyl-CoA mutase. 
C) Enoyl-CoA hydratase. 
D) Propionyl-CoA carboxylase.

Question 9

Double bonds positioned farther than nine carbons from the carboxyl end of fatty acids occur only in vertebrates.

Accepted Answer

A) True 
 B)False

Question 10

Which of the following is mismatched?

Accepted Answer

A) Bile salts - intestinal absorption of lipids. 
B) B-estradiol - sex characteristics. 
C) Cholesterol - membrane fluidity. 
D) Squalene - lipid vitamin. 
A) Bile salts - intestinal absorption of lipids. 
B) B-estradiol - sex characteristics. 
C) Cholesterol - membrane fluidity. 
D) Squalene - lipid vitamin.

Question 11

Why is it undesirable to have high concentrations of free fatty acids in cells?

Accepted Answer

A) They are unstable,free radicals that can react to form toxic substances. 
B) They polymerize easily and can cause the cytosol to become too gel-like. 
C) They are amphipathic and act as detergents that can degrade membranes. 
D) They inhibit the uptake of pyruvate by mitochondria. 
A) They are unstable,free radicals that can react to form toxic substances. 
B) They polymerize easily and can cause the cytosol to become too gel-like. 
C) They are amphipathic and act as detergents that can degrade membranes. 
D) They inhibit the uptake of pyruvate by mitochondria.

Question 12

Which of the following is a true statement,concerning HMG-CoA reductase?

Accepted Answer

A) It is regulated by covalent modification of a serine in its active site. 
B) It catalyzes the first committed step in cholesterol biosynthesis. 
C) It causes the production of NADPH. 
D) The product of the reaction it catalyzes is acetoacetyl CoA. 
A) It is regulated by covalent modification of a serine in its active site. 
B) It catalyzes the first committed step in cholesterol biosynthesis. 
C) It causes the production of NADPH. 
D) The product of the reaction it catalyzes is acetoacetyl CoA.

Question 13

Linoleate is an essential fatty acid in mammalian diets because mammalian cells ________.

Accepted Answer

A) synthesize it from arachidonate 
B) do not use this acid for biosynthesis 
C) can use it to synthesize eicosanoids 
D) do not have a desaturase that acts beyond the carbon-9 position 
A) synthesize it from arachidonate 
B) do not use this acid for biosynthesis 
C) can use it to synthesize eicosanoids 
D) do not have a desaturase that acts beyond the carbon-9 position

Question 14

The role of biotin in fatty acid biosynthesis is in

Accepted Answer

A) elongation. 
B) malonyl CoA formation. 
C) initiation. 
D) ATP activation. 
A) elongation. 
B) malonyl CoA formation. 
C) initiation. 
D) ATP activation.

Question 15

During the fed state,which of the following occur(s)?

Accepted Answer

A) Insulin inhibition of the hydrolysis of stored triacylglycerols. 
B) Insulin stimulation of malonyl CoA formation. 
C) Allosteric inhibition of carnitine acyltransferase I. 
D) All of the above. 
A) Insulin inhibition of the hydrolysis of stored triacylglycerols. 
B) Insulin stimulation of malonyl CoA formation. 
C) Allosteric inhibition of carnitine acyltransferase I. 
D) All of the above.

Question 16

Cholesterol is a precursor for each of the following,except

Accepted Answer

A) bile salts. 
B) vitamin D. 
C) testosterone. 
D) vitamin C. 
A) bile salts. 
B) vitamin D. 
C) testosterone. 
D) vitamin C.

Question 17

Which lipid form is transported across the inner mitochondrial membrane before β-oxidation?

Accepted Answer

A) Acylcarnitine. 
B) Fatty acyl CoA. 
C) Acetoacetyl CoA. 
D) Lysophospholipid CoA. 
A) Acylcarnitine. 
B) Fatty acyl CoA. 
C) Acetoacetyl CoA. 
D) Lysophospholipid CoA.

Question 18

Isopentenyl pyrophosphate is the precursor for which of the following?

Accepted Answer

A) Terpenes. 
B) Vitamin K. 
C) Quinones. 
D) All of the above. 
E) None of the above. 
A) Terpenes. 
B) Vitamin K. 
C) Quinones. 
D) All of the above. 
E) None of the above.

Question 19

What is the main function of the carnitine shuttle system?

Accepted Answer

A) To transport fatty acids into the mitochondrion. 
B) To transport newly synthesized sphingolipids to the blood. 
C) To carry cholesterol from its site of synthesis in the endoplasmic reticulum to the plasma membrane. 
D) To aid in the assembly of chylomicrons. 
A) To transport fatty acids into the mitochondrion. 
B) To transport newly synthesized sphingolipids to the blood. 
C) To carry cholesterol from its site of synthesis in the endoplasmic reticulum to the plasma membrane. 
D) To aid in the assembly of chylomicrons.

Question 20

What is the fate of most glycerol that is released during the hydrolysis of triacylglycerols from adipocytes?

Accepted Answer

A) It is transported to the kidneys and excreted in the urine. 
B) It is used in the synthesis of sphingolipids. 
C) It is converted to glucose via gluconeogenesis in the liver. 
D) It is absorbed by the chylomicrons. 
A) It is transported to the kidneys and excreted in the urine. 
B) It is used in the synthesis of sphingolipids. 
C) It is converted to glucose via gluconeogenesis in the liver. 
D) It is absorbed by the chylomicrons.

Exam 16: Lipid Metabolism

Why are triacylglycerols able to provide more energy than carbohydrates (gram for gram)?

Ketone bodies are normally broken down in the liver in preparation for excretion.

To prepare for elongation reactions of fatty acid synthesis,the "3-keto" group must be reduced to the ________ form by transfer of electrons (and protons)to the 3-carbon position.

Which of the following is a true statement for fatty acid synthesis?

Most of the lipids in the diets of mammals are free fatty acids.

The cyclooxygenase-hydroperoxidase pathway is a precursor for each of the following except

Regulation of acetyl CoA-carboxylase is accomplished by

Which enzyme requires adenosylcobalamin as a cofactor?

Double bonds positioned farther than nine carbons from the carboxyl end of fatty acids occur only in vertebrates.

Which of the following is mismatched?

Why is it undesirable to have high concentrations of free fatty acids in cells?

Which of the following is a true statement,concerning HMG-CoA reductase?

Linoleate is an essential fatty acid in mammalian diets because mammalian cells ________.

The role of biotin in fatty acid biosynthesis is in

During the fed state,which of the following occur(s)?

Cholesterol is a precursor for each of the following,except

Which lipid form is transported across the inner mitochondrial membrane before β-oxidation?

Isopentenyl pyrophosphate is the precursor for which of the following?

What is the main function of the carnitine shuttle system?

What is the fate of most glycerol that is released during the hydrolysis of triacylglycerols from adipocytes?

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

The Citric Acid Cycle

Electron Transport and Atp Synthesis

Photosynthesis

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

DNA Replication, repair, and Recombination

Transcription and RNA Processing

Protein Synthesis

Filters