Fatty Acid Metabolism Chapter.23 Full Test Bank 10th Edition

General, Organic, and Biochemistry, 10e (Denniston)

Chapter 23 Fatty Acid Metabolism

1) What compound serves as the starting material for the biosynthesis of fatty acids and is also a key intermediate in fatty acid metabolism?

A) carnitine

B) glucose

C) bile salt

D) acetyl CoA

E) lactate

2) What is the fate of the acetyl CoA units produced by β-oxidation of fatty acids when there is an immediate need for energy?

A) entry into the citric acid cycle

B) entry into the oxidative phosphorylation pathway

C) synthesis of triglycerides

D) synthesis of glycogen

E) synthesis of glucose

3) Which statement concerning the steps in the digestion of dietary triglycerides is FALSE?

A) The digestion of triglycerides begins in the mouth with the aid of bile salts.

B) Lipases hydrolyze triglycerides to fatty acids and monoglycerides in the small intestine.

C) The monoglycerides and fatty acids reassemble in the membrane of the small intestine to form triglycerides.

D) The triglycerides combine with proteins to form chylomicrons for transport to the lymphatic system and bloodstream.

E) In the bloodstream, triglycerides are hydrolyzed to glycerol and three fatty acids that are then absorbed by the cells.

4) Which protein binds to the surface of a lipid droplet and helps pancreatic lipases to adhere to the surface and hydrolyze triglycerides?

A) colipase

B) cholic acid

C) chenodeoxycholic acid

D) insulin

E) glucagon

5) The fourth reaction in β-oxidation of fatty acids is shown below and involves the oxidation of the β-carbon. What is the product of this reaction?

A)

B)

C)

D)

E)

6) What is the primary function of bile salts in fatty acid metabolism?

A) to hydrolyze triglycerides into glycerol and fatty acids

B) to hydrolyze triglycerides into monoglycerides and fatty acids

C) to break down and emulsify large fat globules to make them more readily hydrolyzable by lipases

D) to transport triglycerides through the lymphatic system and into the bloodstream

E) to activate fatty acids in preparation for β-oxidation

7) The fat cells that make up adipose tissue are capable of storing unlimited amounts of triglycerides. What are these fat cells called?

A) globucytes

B) lymphocytes

C) glycerocytes

D) lipocytes

E) adipocytes

8) Fatty acids must first be activated before undergoing β-oxidation. This activation involves which of the following processes?

A) combination of the fatty acid with coenzyme A to yield fatty acyl CoA

B) oxidation of the fatty acid by NAD+

C) joining of the fatty acid to ATP

D) decarboxylation of the fatty acid to form a smaller molecule, which can easily enter the mitochondria

E) neutralization of the fatty acid by a base

9) What compound is released in the final step of β-oxidation of fatty acids?

A) acetic acid

B) CO2

C) acetyl CoA

D) carnitine

E) glycerol

10) What products are formed in the complete β-oxidation of the ω-labeled fatty acid 10-phenyldecanoic acid, shown below?

A)

B)

C)

D)

E) This compound does not undergo β-oxidation.

11) The structure below represents a fatty acyl CoA molecule, formed in the first step of β-oxidation of a fatty acid. Which of the following statements concerning this compound is TRUE?

A) The wavy line indicates a partially formed thioester bond.

B) The wavy line indicates an ionic bond between the fatty acid and coenzyme A.

C) The wavy line indicates a high-energy thioester bond.

D) The wavy line indicates a highly polar bond between the fatty acid and coenzyme A.

E) The wavy line indicates a partially formed disulfide bond.

12) What type of compound is produced from acetyl CoA when there is insufficient oxaloacetate to allow all the acetyl CoA to enter the citric acid cycle?

A) amino acids

B) glycogen

C) disaccharides

D) ketone bodies

E) nucleotides

13) What metabolic pathway produces β-hydroxybutyrate, acetone, and acetoacetate?

A) β-oxidation

B) ketogenesis

C) acidosis

D) lipogenesis

E) glycolysis

14) Why must dietary triglycerides be processed before digestion begins?

A) Dietary triglycerides are large, hydrophobic molecules that must be emulsified by bile salts in order for lipases to be effective.

B) Dietary triglycerides are more stable and undergo hydrolysis more readily when they are bound to the surface of micelles.

C) Dietary triglycerides contain glycerol as part of their structure; glycerol is toxic to the cell and must first be removed.

D) Dietary triglycerides are acidic molecules that must be made basic for entry into the small intestine.

E) Dietary triglycerides are basic molecules that must be made acidic for entry into the small intestine.

15) Which statement describing β-oxidation of fatty acids and fatty acid biosynthesis is FALSE?

A) β-Oxidation occurs in the mitochondria.

B) The acyl group carrier in β-oxidation is coenzyme A.

C) The electron carriers in β-oxidation and biosynthesis are NADH and FADH2.

D) The acyl group carrier in biosynthesis is acyl carrier protein (ACP).

E) Biosynthesis occurs in the cytoplasm.

16) Which type of lipoprotein complex transports triglycerides made by the liver to adipose tissue?

A) chylomicrons

B) coenzyme A

C) adipocytes

D) very low density lipoproteins (VLDL)

E) triglyceride transportase complex

17) What is the source of energy for the activation of a fatty acid in β-oxidation?

A) phosphorylation of AMP

B) hydrolysis of the thioester bond in acetyl CoA

C) hydrolysis of ATP to AMP

D) conversion of NADH to NAD+

E) oxidation of glycerol

18) What is the major storage form of fatty acids in the body?

A) glycogen

B) triglycerides

C) cellulose

D) protein

E) lipoproteins

19) The third reaction in β-oxidation of fatty acids is shown below, and involves hydration of the double bond. What is the product of this reaction?

A)

B)

C)

D)

E)

20) What process generally supplies the energy requirements of resting muscle?

A) glycolysis

B) protein degradation

C) urea cycle

D) β-oxidation of fatty acids

E) glycogenolysis

21) Insulin acts only on those cells that have insulin receptor protein in their plasma membranes. What is the general name given to these cells?

A) adipocytes

B) plasmatic cells

C) benign cells

D) factor cells

E) target cells

22) Insulin acts only on those cells that have insulin receptor protein in their plasma membranes. Which of the following cell types are target cells for insulin?

A) liver

B) adipose

C) muscle

D) liver and muscle

E) All of these are correct.

23) What general class of enzymes catalyzes the hydrolysis of triglycerides?

A) glycerases

B) lipases

C) oxidases

D) reductases

E) hydroxylases

24) What substance is secreted by the gallbladder in response to the presence of fat globules in the duodenum?

A) insulin

B) bile

C) hydrochloric acid

D) β-oxidase

E) Both insulin and bile are correct.

25) What class of plasma lipoproteins is formed in intestinal cells when triglycerides are combined with protein?

A) endoplasmic reticulum

B) monoglycerides

C) triglycerides

D) chylomicrons

E) None of the choices are correct.

26) What is the primary function of the β-oxidation pathway?

A) to break down triglycerides into fatty acids and glycerol

B) to synthesize fatty acids from the glycogen reserves in the body

C) to synthesize triglycerides from the fatty acid stores in the body

D) to completely degrade fatty acids into two-carbon acetyl CoA units

E) to degrade two-carbon acetyl CoA units into CO2 and H2O

27) Which of the following is NOT one of the ketone bodies produced in ketogenesis?

A) β-hydroxybutyrate

B) acetone

C) sodium acetate

D) acetoacetate

E) All of the choices are ketone bodies.

28) The pathway for the production of ketone bodies begins with a reversal of the last step of another pathway. What is this pathway?

A) urea cycle

B) β-oxidation

C) α-reduction

D) β-reduction

E) citric acid cycle

29) What is the name of the multi-enzyme complex that carries out the seven steps of fatty acid biosynthesis?

A) fatty acid synthase

B) fatty acid conglomerate

C) NADH

D) fatty acid lipase

E) ACP

30) In the disease diabetes mellitus, what is the meaning and relevance of the word "mellitus"?

A) "lack of insulin," causing inability to digest sugar

B) "sweetened with honey," due to the high amount of sugar in urine

C) "drunken stupor," due to the state of a diabetic coma

D) "waste away," from the starvation from the inability to digest sugar

E) "blind," due to the common complication of diabetes

31) Insulin stimulates glycogen formation while it simultaneously inhibits two other processes. What two processes does it inhibit?

A) glycogenolysis and gluconeogenesis

B) gluconeogenesis and ketogenesis

C) glycogenolysis and lipolysis

D) ketogenesis and lipolysis

E) lipolysis and glycogenolysis

32) Which of the following correctly describes the activation and inhibition by insulin?

A) Insulin activates anabolic processes and inhibits catabolic processes.

B) Insulin activates dehydration processes and inhibits biosynthetic processes.

C) Insulin activates catabolic processes and inhibits anabolic processes.

D) Insulin activates biosynthetic processes and inhibits anabolic processes.

E) Insulin activates anabolic processes and inhibits biosynthetic processes.

33) Bile salts act as which of the following?

A) detergents

B) enzymes

C) fatty acids

D) amino acids

E) lipoproteins

34) Where in the cell are the enzymes responsible for the degradation of fatty acids located?

A) endosomes

B) mitochondria

C) liposomes

D) cytoplasm

E) nucleus

35) The ketone bodies β-hydroxybutyrate, acetone, and acetoacetate are shown below. Which ketone bodies are responsible for the condition known as ketoacidosis?

A) acetone

B) acetoacetate

C) β-hydroxybutyrate

D) acetoacetate and β-hydroxybutyrate

E) All three ketone bodies are responsible for ketoacidosis.

36) How many molecules of acetyl CoA will be formed during the β-oxidation of a fatty acid containing a chain of ten carbon atoms?

A) 2

B) 3

C) 4

D) 5

E) 10

37) How many molecules of ATP are produced by the complete oxidation of palmitate, a 16-carbon fatty acid?

A) 4

B) 36

C) 64

D) 106

E) 129

38) Which two electron carriers are produced in each cycle of β-oxidation?

A) NADH and NADPH

B) NADH and FAD

C) NAD+ and FAD

D) NADH and FADH2

E) NADPH and FADH2

39) Which one of the following is a "ketone body"?

A) pyruvate

B) citrate

C) oxaloacetate

D) acetyl CoA

E) acetoacetate

40) When the ketone body acetoacetate undergoes reduction of the ketone carbonyl group, β-hydroxybutyrate, another ketone body, is formed. What is the structure of β-hydroxybutyrate?

A)

B)

C)

D)

E)

41) Where in the cell are the enzymes responsible for fatty acid biosynthesis located?

A) endosomes

B) mitochondria

C) liposomes

D) cytoplasm

E) nucleus

42) Which coenzyme form is the reducing agent for fatty acid biosynthesis?

A) NAD+

B) NADH

C) NADPH

D) FADH2

E) FAD

43) During fatty acid biosynthesis, to what substance are the activated intermediates bound?

A) coenzyme A

B) acyl carrier protein

C) VLDL

D) ATP

E) fatty acid synthase

44) What condition leads to the production of ketone bodies from acetyl CoA?

A) low blood pH

B) low supply of oxaloacetate in the citric acid cycle

C) high levels of ATP

D) high blood pH

E) low supply of carnitine in β-oxidation

45) The acetyl CoA that is metabolized in the morning before breakfast is mostly derived from the catabolism of what types of molecules?

A) proteins

B) carbohydrates

C) amino acids

D) glycogen

E) fatty acids

46) Which organ provides a steady supply of glucose for muscle and brain tissues and plays a major role in the regulation of blood glucose levels?

A) liver

B) stomach

C) small intestine

D) islets of Langerhans

E) gallbladder

47) What compound stored in working muscles is degraded when the muscles require energy?

A) fructose

B) acetyl CoA

C) acetone

D) amino acids

E) glycogen

48) What organ accounts for about 60% of the free glucose usage when the body is in the resting state?

A) heart

B) brain

C) liver

D) muscle

E) adipose

49) Which of the following processes is inhibited by insulin?

A) glycogenolysis

B) citric acid cycle

C) glycolysis

D) pyruvate synthesis

E) glycogenesis

50) What is the function of malonyl ACP in the biosynthesis of fatty acids?

A) to oxidize the β-carbon of the growing fatty acid chain

B) to add two-carbon units to the growing fatty acid chain

C) to shorten the fatty acid chain by two-carbon units

D) to isomerize the trans double bonds in fatty acids to cis double bonds

E) None of these are correct; malonyl ACP is used in β-oxidation of fatty acids.

51) Which of the following hormones inhibits the breakdown of lipids?

A) glucagon

B) insulin

C) progesterone

D) prostaglandins

E) cholesterol

52) Which of the following hormones is secreted by the α-cells of the islets of Langerhans in response to decreased blood glucose levels?

A) cortisone

B) insulin

C) glucagon

D) adrenalin

E) epinephrine

53) Which of the following hormones increases blood glucose levels by inducing the breakdown of glycogen and the production of glucose by gluconeogenesis?

A) glucagon

B) insulin

C) cortisone

D) adrenalin

E) cholesterol

54) Uncontrolled diabetes mellitus can lead to the overproduction of ketone bodies, which can affect the acidity of the blood. This results in which of the following conditions?

A) alkalosis

B) hypoxia

C) ketoacidosis

D) crenation

E) cancer

55) What component of bile is required to form micelles of triglycerides in the duodenum?

A) lecithin

B) cholesterol

C) protein

D) bile salts

E) inorganic ions

56) What is the function of lipase enzymes on triglycerides?

A) Lipase enzymes emulsify triglycerides.

B) Lipase enzymes hydrolyze triglycerides.

C) Lipase enzymes allow triglycerides to be stored in adipose tissue.

D) Lipase enzymes oxidize triglycerides.

E) Lipase enzymes reduce triglycerides.

57) What is the major storage site for triglycerides?

A) in the cells of the small intestine

B) in mitochondria

C) in the cytoplasm of adipocytes

D) in mitochondria and in the cytoplasm of adipocytes

E) All of the choices are correct.

58) Each cycle through β-oxidation releases what substance from the fatty acid?

A) acetyl CoA

B) CO2

C) phenyl acetate

D) ATP

E) acetic acid

59) How many acetyl CoA units can be produced from palmitic acid, a fatty acid with the formula CH3(CH2)14COOH?

A) 16

B) 14

C) 10

D) 8

E) 7

60) Which statement concerning the complete oxidation of arachidic acid, CH3(CH2)18COOH, is true?

A) Energy equivalent to two ATP molecules is used to activate arachidic acid for β-oxidation.

B) Arachidic acid undergoes 9 cycles of β-oxidation.

C) Arachidic acid produces 10 acetyl CoA molecules.

D) The energy yield is 163 molecules of ATP.

E) All of the statements are true.

61) Which of the following is NOT a major difference between fatty acid synthesis and fatty acid degradation?

A) the location of the process

B) the groups that carry the acetyl groups involved

C) the enzymes involved

D) the electron carriers

E) the number of carbon atoms in the acetyl groups

62) Lipases hydrolyze triglycerides.

63) Cholesterol is one component of human bile.

64) Chylomicrons are composed of amino acids and lipids.

65) Triacylglycerols and triglycerides are two names for the same type of compounds.

66) The final step in β-oxidation of fatty acids is the release of acetoacetic acid.

67) In each cycle of β-oxidation, the carbon chain of a fatty acid is shortened by two carbon atoms.

68) Complete oxidation of fatty acids yields more energy than complete oxidation of an equal mass of glucose.

69) Methyl isobutyl ketone is a ketone body.

70) Biosynthesis of fatty acids takes place in the mitochondria.

71) NADPH serves as a reducing agent in the biosynthesis of fatty acids.

72) One of insulin's effects is to inhibit biosynthesis of lipids.

73) The heart muscle prefers ketone bodies over glucose as its energy source.

74) Insulin and glucagon have the same biochemical function.

75) Emulsification of dietary lipids produces a solution of fat in water.