General organic and biological chemistry 5e timberlack test bank chapter 24

Answer: A Objective: 24.1 Global Outcomes: GO2 3 Fatty acids and glycerol are produced from the metabolism of A lipids.. Answer: C Objective: 24.1 Global Outcomes: GO2 15 Most of the gly

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General, Organic & Biological Chemistry, 5e (Timberlake)

Chapter 24 Metabolic Pathways for Lipids and Amino Acids

24.1 Multiple-Choice Questions

1) The digestion of fats begins in the

A) mouth

B) stomach

C) small intestine

D) large intestine

E) pancreas

Answer: C

Objective: 24.1

Global Outcomes: GO2

2) The digestion of fats begins when the fat globules are

A) emulsified by bile salts

B) attacked by protease enzymes to form smaller fat globules

C) converted to lipoproteins for greater solubility

D) hydrolyzed to glucose and amino acids

E) hydrolyzed to glycerol and fatty acids

Answer: A

Objective: 24.1

3) Fatty acids and glycerol are produced from the metabolism of

A) lipids

B) proteins

C) carbohydrates

D) amino acids

E) glucose

Answer: A

Objective: 24.1

4) Most of the energy stored in the human body is in the form of

A) glycogen

B) glucose

C) muscle tissue

D) triacylglycerols

E) the amino acid pool

Answer: D

Objective: 24.1

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5) Fat cells are known as

A) lysosomes

B) adipocytes

C) glycerides

D) islet cells

E) monoacylglycerols

Answer: B

Objective: 24.1

6) The small droplets of fat that are the first step in the digestion of dietary fats are called A) emulsions

B) detergents

C) bile drops

D) lipoproteins

E) micelles

Answer: E

Objective: 24.1

7) The action of pancreatic lipase on triacylglycerols produces

A) emulsions

B) micelles

C) monoacylglycerols and free fatty acids

D) high-density lipoproteins

E) low-density lipoproteins

Answer: C

Objective: 24.1

8) A chylomicron is a

A) lipase

B) digestive enzyme

C) triacylglycerol

D) transport lipoprotein

E) storage protein

Answer: D

Objective: 24.1

9) Fatty acids are not a source of energy for the brain because

A) they cannot diffuse across the blood-brain barrier

B) the citric acid cycle does not operate in the brain

C) chylomicrons are too large for absorption by brain cells

D) they are metabolized before they get as far as the brain

E) there is no lipase in the brain

Answer: A

Objective: 24.1

10) The source of energy for red blood cells is

A) amino acids

B) fatty acids

C) glycerol

D) glucose

E) lactate

Answer: D

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Objective: 24.1

11) The heart muscle's primary source of fuel is

A) glucose

B) fatty acids

C) amino acids

D) glycogen

E) lactate

Answer: B

Objective: 24.1

12) Red blood cells do not metabolize fatty acids because they have

A) no nucleus

B) a cell wall

C) a cell membrane

D) no mitochondria

E) no DNA

Answer: D

Objective: 24.1

13) Fat stores in the body are mobilized when

A) adipocyte concentrations are high

B) blood glucose levels are high

C) glucagon production is low

D) insulin production is high

E) glucose and glycogen stores are low

Answer: E

Objective: 24.1

14) The enzymes that break down triacylglycerols into fatty acids and glycerol are called A) lyases

B) aconitases

C) lipases

D) hydrolases

E) oxidoreductases

Answer: C

Objective: 24.1

15) Most of the glycerol produced by fatty acid breakdown goes to the

A) pancreas

B) gall bladder

C) liver

D) small intestine

E) brain

Answer: C

Objective: 24.1

16) Most of the glycerol produced by fatty acid breakdown is converted eventually to A) glucose

B) protein

C) fat

D) lactate

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E) amino acids.

Answer: A

Objective: 24.1

17) The removal of 2-carbon segments of a fatty acid for further metabolism is called

A) β oxidation.

B) transamination

C) deglyceration

D) dehydration

E) decarboxylation

Answer: A

Objective: 24.2

18) The 2-carbon segments removed from a fatty acid during metabolism are used to form A) glucose

B) pyruvate

C) lactate

D) CoA

E) acetyl CoA

Answer: E

Objective: 24.2

19) The series of reactions that produces energy by hydrolyzing fats to units of acetyl CoA is called

A) transamination

B) β oxidation.

C) hydration

D) hydrolysis

E) β reduction.

Answer: B

Objective: 24.2

20) Which step is found in the breakdown of a fat?

A) an activation that requires 1 ATP

B) an oxidation with a cytochrome

C) an oxidation with CoQ

D) direct substrate phosphorylation

E) production of pyruvate

Answer: A

Objective: 24.2

21) During complete oxidation of the fatty acid CH3(CH2)18COOH, molecules of

acetyl CoA are produced, and the fatty acid goes through the β-oxidation cycle

times

A) ten; ten

B) nine; ten

C) nine; nine

D) nine; eight

E) ten; nine

Answer: E

Objective: 24.2

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22) In the activation of a fatty acid, energy from the hydrolysis of ATP is used to

A) form a double bond in an oxidation reaction

B) join the fatty acid to CoA

C) add a molecule of water across a double bond to give a hydroxyl group on the β carbon D) oxidize the hydroxyl group on the β carbon.

E) cause a unit of acetyl CoA to separate from the fatty acid chain

Answer: B

Objective: 24.2

23) The 2-carbon units obtained by degradation of a fatty acid are further metabolized in A) gluconeogenesis

B) the citric acid cycle

C) β oxidation.

D) glycolysis

E) transamination

Answer: B

Objective: 24.2

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24) The function of fatty acyl CoA is to

A) activate a fatty acid for metabolism

B) produce a 2-carbon segment for metabolism

C) isomerize cis fatty acids

D) cross the blood-brain barrier

E) produce a lipoprotein

Answer: A

Objective: 24.2

25) Fatty acyl CoA cannot cross into the mitochondrial matrix until

A) it is cut into 2-carbon segments

B) the citric acid cycle has begun

C) β oxidation has taken place.

D) the mitochondrial membrane undergoes a modification

E) it binds with a charged carrier molecule called carnitine

Answer: E

Objective: 24.2

26) Beta-oxidation takes place in the

A) nucleus

B) cytosol

C) cytoplasm

D) mitochondrial matrix

E) Golgi body

Answer: D

Objective: 24.2

27) What is the total number of ATP molecules produced from the lauric acid (C12H24O2) found in coconut oil?

A) 78 ATP

B) 90 ATP

C) 100 ATP

D) 97 ATP

E) 95 ATP

Answer: A

Objective: 24.3

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28) The complete oxidation of CH3(CH2)8COOH produces molecules of ATP A) 80

B) 78

C) 82

D) 64

E) 76

Answer: D

Objective: 24.3

29) Myristic acid, a C14 fatty acid, produces acetyl CoA when completely metabolized

A) 2

B) 5

C) 7

D) 12

E) 14

Answer: C

Objective: 23.3

30) Myristic acid, a C14 fatty acid, undergoes the β-oxidation cycle times.

A) 2

B) 4

C) 6

D) 7

E) 14

Answer: C

Objective: 23.3

31) The energy released by the β oxidation of a cis fatty acid is

A) slightly more than that obtained from a trans fatty acid.

B) slightly less than that obtained from a trans fatty acid

C) the same as that obtained from a trans fatty acid.

D) less than that obtained from one glucose molecule

E) used immediately to form ATP

Answer: B

Objective: 23.3

32) Fats are higher in caloric value than carbohydrates because

A) 1 gram of fat produces significantly more ATP than 1 gram of glucose

B) fats can make use of the citric acid cycle

C) fats make use of β oxidation.

D) 1 gram of glucose weighs more than 1 gram of fat

E) 1 gram of glucose contains more moles than 1 gram of fat

Answer: A

Objective: 24.3

33) Leptin is

A) a digestive enzyme

B) a cofactor for fatty acid oxidation

C) an obesity gene

D) a zymogen

E) a hormone stored in fat cells

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Answer: E

Objective: 24.3

34) Each acetyl CoA produces ATP in the citric acid cycle

A) 2

B) 6

C) 10

D) 12

E) 24

Answer: C

Objective: 24.3

35) When excess acetyl CoA accumulates in the liver, a pathway called is initiated A) transamination

B) glycolysis

C) gluconeogenesis

D) emulsification

E) ketogenesis

Answer: E

Objective: 24.4

36) Ketosis is a condition that can occur if

A) ketone bodies cannot be completely metabolized

B) too many ketones are ingested

C) too much protein is available in the diet

D) the brain is starved of glucose

E) low fat intake occurs

Answer: A

Objective: 24.4

37) In Type II diabetes mellitus,

A) blood glucose levels are too low

B) glucose intake is too low

C) birth of a baby restores normal pancreatic function

D) sufficient insulin is produced, but cannot be used

E) the pancreas produces insufficient insulin

Answer: D

Objective: 24.4

38) Ketosis can lower the blood pH below 7.4, producing the condition

A) anemia

B) hyponatremia

C) hypokalemia

D) acidosis

E) alkalosis

Answer: D

Objective: 24.4

39) In Type I diabetes mellitus,

A) blood glucose levels are too low

B) glucose intake is too low

C) birth of a baby restores normal pancreatic function

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D) sufficient insulin is produced, but cannot be used.

E) the pancreas produces insufficient insulin

Answer: E

Objective: 24.4

40) Malonyl CoA contains a 3-carbon compound used in

A) lipogenesis

B) acetyl CoA formation

C) gluconeogenesis

D) glycogenolysis

E) the citric acid cycle

Answer: A

Objective: 24.5

41) The letters ACP stand for

A) acetyl Coenzyme P

B) aconitate protein complex

C) acetyl condensing protein

D) acyl carrier protein

E) acetyl CoA-palmitate

Answer: D

Objective: 24.5

42) Fatty acid synthesis takes place primarily in

A) liver cells

B) intestinal cells

C) brain cells

D) muscle cells

E) adipocytes

Answer: E

Objective: 24.5

43) The production of new fatty acids is called

A) gluconeogenesis

B) β oxidation.

C) transesterification

D) oxidation

E) lipogenesis

Answer: E

Objective: 24.5

44) Acyl carrier protein is used in

A) β oxidation.

B) lipogenesis

C) gluconeogenesis

D) acetyl CoA production

E) fatty acid degradation

Answer: B

Objective: 24.5

45) The coenzyme(s) used in fatty acid synthesis is (are)

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A) NADH.

B) FADH2

C) NADPH

D) NADH and NADPH

E) FADH2 and NADH

Answer: C

Objective: 24.5

46) The digestion of protein begins in the

A) mouth

B) stomach

C) small intestine

D) large intestine

E) pancreas

Answer: B

Objective: 24.6

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47) The initial digestion of protein is catalyzed by an enzyme called

A) chymotrypsin

B) peptidase

C) pepsin

D) amylase

E) trypsin

Answer: C

Objective: 24.6

48) In a(n) reaction, NH4+is produced when glutamate is converted to

α-ketoglutarate

A) dehydrogenation

B) transamination

C) oxidative deamination

D) reduction

E) hydration

Answer: C

Objective: 24.6

49) The nitrogen for nucleotide synthesis comes from

A) carbohydrates

B) fats

C) proteins

D) DNA

E) RNA

Answer: C

Objective: 24.6

50) Which of the following does NOT require NAD+?

A) glycolysis

B) transamination

C) citric acid cycle

D) β oxidation

E) oxidative deamination

Answer: B

Objective: 24.6

51) In mammals, the ammonium ion produced in oxidative deamination is

A) excreted in the feces

B) stored in the liver

C) converted to uric acid, which is excreted in the urine

D) converted to urea, which is excreted in the urine

E) converted to uric acid, which is excreted by the liver

Answer: D

Objective: 24.7

52) In the urea cycle, argininosuccinase synthase catalyzes the reaction of arginosuccunate to

A) citurulline

B) carbomyl phosphate

C) orthinine

D) arginine

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E) arginase.

Answer: D

Objective: 24.7

53) Which metabolic substrate can be produced from the carbon atoms in the amino acid lysine?

A) pyruvate

B) succinyl CoA

C) acetoacetyl CoA

D) fumarate

Answer: C

Objective: 24.8

54) Which metabolic substrate can be produced from the carbon atoms in the amino acid phenylalanine?

A) pyruvate

B) succinyl CoA

C) acetoacetyl CoA

D) fumarate

Answer: D

Objective: 24.8

55) Which metabolic substrate can be produced from the carbon atoms in the amino acid valine?

A) pyruvate

B) succinyl CoA

C) acetoacetyl CoA

D) fumarate

Answer: B

Objective: 24.8

56) All of the nonessential amino acids can be synthesized in the body by transamination, using an amino group from

A) glutamate

B) α-ketoglutarate.

C) pyruvate

D) oxaloacetate

E) lactic acid

Answer: A

Objective: 24.9

24.2 True/False Questions

1) Fatty acids can be used in the brain as an energy source

Answer: FALSE

Objective: 24.1

2) Red blood cells have mitochondria, which serve as an energy production site

Answer: FALSE

Objective: 24.1

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3) Chylomicrons consist of bile salts and lipids.

Answer: FALSE

Objective: 24.1

4) β oxidation adds two-carbon segments to a fatty acid chain

Answer: FALSE

Objective: 24.2

5) A ten carbon saturated fatty acid will undergo five β oxidation cycles

Answer: FALSE

Objective: 24.3

6) Each acetyl CoA that enters the citric acid cycle yields 10 ATP

Answer: TRUE

Objective: 24.3

7) A ten carbon saturated fatty acid will produce five acetyl CoAs

Answer: TRUE

Objective: 24.3

8) The production of new triacylglycerols is termed ketogenesis

Answer: FALSE

Objective: 24.4

9) A low level of acetyl CoA in the cell leads to ketogenesis

Answer: FALSE

Objective: 24.4

10) Acyl carrier protein is used in fatty acid synthesis

Answer: TRUE

Objective: 24.5

11) Protein digestion begins in the small intestine

Answer: FALSE

Objective: 24.6

12) Some amino acids can be converted into others via transamination

Answer: TRUE

Objective: 24.6

13) The overall process of synthesizing and breaking down proteins is called protein turnover

Answer: TRUE

Objective: 24.6

14) Ammonium ions and carbon dioxide produce urea in the urea cycle

Answer: TRUE

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Objective: 24.7

15) The urea cycle is the major pathway for eliminating the excess nitrogen from amino acid degradation

Answer: TRUE

Objective: 24.7

16) The amino acid valine enters the citric acid cycle as succinyl CoA

Answer: TRUE

Objective: 24.8

17) Nonessential amino acids can be made by transamination

Answer: TRUE

Objective: 24.9

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