Deck 27: Specific Catabolic Pathways: Carbohydrate, Lipid, and Protein Metabolism

Question 1

Which of the following is not involved in the hydrolysis of proteins?

A) HCl
B) NaOH
C) intestinal enzymes
D) stomach enzymes

Answer 1

B

Question 2

Which of the following compounds is not a product of lipase-catalyzed lipid hydrolysis?

A) amino acid
B) fatty acid
C) monoglyceride
D) none of these

Answer 2

A

Question 3

In which form do the carbon skeletons of amino acids enter the common catabolic pathway?

A) as the side chain of amino acids
B) as proteins
C) as α-ketoacids
D) as glycerol

Answer 3

C

Question 4

What is the role of phosphofructokinase in glycolysis?

A) It converts fructose into fructose 1-phosphate.
B) It converts fructose 1-phosphate into fructose 1,6-bisphosphate.
C) It converts fructose 1,6-bisphosphate into glucose 1,6-bisphosphate.
D) None of these are correct.

Question 5

To which of the following processes does the first three steps of glycolysis belong?

A) the activation process
B) the initiation process
C) the initialization process
D) the preparation process

Question 6

Which of the following pathways is used by cells to obtain energy from fatty acids?

A) α-oxidation
B) α-reduction
C) β-oxidation
D) β-reduction

Question 7

Which of the following digestive enzymes is found in the intestines?

A) carboxypeptidase
B) chymotrypsin
C) trypsin
D) all of these

Question 8

Which of the following digestive enzymes is found in the stomach?

A) carboxypeptidase
B) chymotrypsin
C) pepsin
D) trypsin

Question 9

Identify an enzyme that catalyzes the first step of glycolysis.

A) hexokinase
B) phosphohexose isomerase
C) aldolase
D) phosphoglycerate kinase

Question 10

Which of the following assists the breakdown of di- and polysaccharides into monosaccharides?

A) enzymes
B) stomach acid
C) both enzymes and stomach acid
D) neither enzymes nor stomach acid

Question 11

Why must carbohydrates, fats, and proteins be broken down into small molecules during digestion?

A) to facilitate their absorption by the walls of the stomach
B) to facilitate their absorption by the walls of the intestines
C) to facilitate their proper excretion
D) to facilitate the removal of contaminants

Question 12

Which of the following are needed to convert fructose 6-phosphate to fructose 1,6-bisphosphate?

A) phosphofructokinase and Ca2+
B) phosphofructokinase, ADP, and Ca2+
C) phosphofructokinase, ADP, and Mg2+
D) phosphofructokinase, ATP, and Mg2+

Question 13

In which form do the carbon skeletons of amino acids enter the common catabolic pathway?

A) as the side chain of amino acids
B) as part of complete proteins
C) as acetyl coenzyme A
D) as monosaccharides

Question 14

Identify a true statement regarding the pathways used to extract energy from carbohydrates and glycerol.

A) Both carbohydrates and glycerol utilize the β-oxidation pathway to extract energy.
B) Both carbohydrates and glycerol utilize the glycolytic pathway to extract energy.
C) Carbohydrates utilize glycolysis, whereas glycerol utilizes the β-oxidation pathway to extract energy.
D) Carbohydrates utilize the β-oxidation pathway, whereas glycerol utilizes glycolysis to extract energy.

Question 15

What is the relationship between dihydroxyacetone phosphate and glyceraldehyde 3-phosphate?

A) They are anomers of each other.
B) They are enantiomers of each other.
C) They are isomers of each other.
D) They are not related to each other.

Question 16

Which of the following statements is true of the amino acids in the amino acid pool?

A) They are never used as a fuel for energy.
B) They are occasionally used as a fuel for energy.
C) They regulate the degradation of proteins.
D) They regulate the level of glucose in the blood.

Question 17

Which of the following compounds is a product of lipase-catalyzed lipid hydrolysis?

A) fatty acid
B) glycerol
C) monoglyceride
D) all of these

Question 18

What is the relationship between glucose 6-phosphate and fructose 6-phosphate?

A) They are anomers of each other.
B) They are enantiomers of each other.
C) They are isomers of each other.
D) They are not related to each other.

Question 19

What is the amino acid pool?

A) the amino acids found in our diets
B) the free amino acids found both inside and outside cells
C) the conjugate forms of amino acids found in nature
D) the synthetic analogues of the natural amino acids

Question 20

Which of the following compounds is the product of the first step of glycolysis?

A) fructose
B) glucose
C) glucose 1-phosphate
D) glucose 6-phosphate

Question 21

Which enzyme is involved in the conversion of phosphoenolpyruvate to pyruvate?

A) enolase
B) ketolase
C) pyruvate kinase
D) pyruvate oxidase

Question 22

Which of the following statements is true of pyruvate kinase?

A) It is activated by AMP.
B) It plays a key regulatory role in glycolysis.
C) Both of these are true.
D) Neither of these is true.

Question 23

What is the effect of excess ATP on glycolysis?

A) It enhances the rate of glycolysis.
B) It moderately reduces the rate of glycolysis.
C) It shuts down glycolysis.
D) It has no effect on glycolysis.

Question 24

To which of the following reactions does the conversion of ribose to deoxyribose belong?

A) dehydration
B) oxidation
C) reduction
D) phosphorylation

Question 25

The conversion of glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate is a(n) _____ reaction.

A) hydrolysis
B) isomerization
C) oxidation
D) reduction

Question 26

What is the by-product of the reaction that is involved in the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate?

A) AMP
B) ADP
C) ATP
D) none of these

Question 27

What is the role of the enzyme phosphoglycerate mutase?

A) It catalyzes the hydrolysis of 3-phosphoglycerate.
B) It catalyzes the isomerization of 3-phosphoglycerate.
C) It catalyzes the oxidation of 3-phosphoglycerate.
D) It catalyzes the reduction of 3-phosphoglycerate.

Question 28

Which of the following reactions is involved in the conversion of pyruvate to acetyl coenzyme A?

A) oxidative phosphorylation
B) oxidative deamination
C) oxidative decarboxylation
D) oxidative transamination

Question 29

Which of the following is the main agent that is used to keep hemoglobin in its reduced form?

A) ATP
B) FAD
C) glutathione
D) nicotinamide

Question 30

Which of the following pathways has the capacity to produce NADPH and ribose?

A) the glycolytic pathway
B) the citric acid cycle
C) the Krebs cycle
D) the pentose phosphate pathway

Question 31

Which of the following reactions is involved in the conversion of 3-phosphoglycerate from 1,3-bisphosphoglycerate?

A) addition
B) dephosphorylation
C) phosphorylation
D) oxidation

Question 32

Which of the following statements is true of anaerobic reactions?

A) They are all redox reactions.
B) They are all oxidation reactions.
C) They occur in the presence of oxygen.
D) They occur in the absence of oxygen.

Question 33

Which of the following is the cause of muscle cramps associated with strenuous exercise?

A) acetate accumulation in muscles
B) citrate accumulation in muscles
C) lactate accumulation in muscles
D) pyruvate accumulation in muscles

Question 34

Which of the following statements is true of the reactions of glycolysis?

A) All the reactions of glycolysis occur in the cytoplasm.
B) All the reactions of glycolysis occur in the mitochondria.
C) All the reactions of glycolysis occur in the presence of oxygen.
D) All the reactions of glycolysis require ATP as an energy source.

Question 35

Which of the following acts as the oxidizing agent in the conversion of pyruvate to acetyl coenzyme A?

A) ATP
B) NAD⁺
C) NADH
D) pyruvate

Question 36

Which of the following compounds is required to convert glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate?

A) ADP
B) ATP
C) NADH
D) NAD+

Question 37

Which of the following gases is a by-product of the reaction between pyruvate and coenzyme A?

A) CO
B) CO₂
C) O₂
D) none of these

Question 38

Which of the following chemicals causes most of the damage in fetal alcohol syndrome?

A) acetaldehyde
B) acetic acid
C) acetone
D) ethanol

Question 39

Which of the following processes requires NADPH?

A) synthesis of amino acids
B) synthesis of cholesterol
C) synthesis of unsaturated fatty acids
D) all of these

Question 40

Which of the following statements is true of pyruvate kinase?

A) It is activated by ATP.
B) It plays a key regulatory role in glycolysis.
C) Both of these are true.
D) Neither of these is true.

Question 41

Which of the following statements is true of NADH and H⁺ molecules produced during glycolysis?

A) They are produced in the cytoplasm; hence, they can be used directly in oxidative phosphorylation.
B) They are produced in the mitochondria; hence, they can be used directly in oxidative phosphorylation.
C) They are produced in the cytoplasm; hence, they cannot be used directly in oxidative phosphorylation.
D) They are produced in the mitochondria; hence, they cannot be used directly in oxidative phosphorylation.

Question 42

Which of the following is the activated form of fatty acids in the β-oxidation pathway?

A) free fatty acid
B) fatty acetyl CoA
C) fatty acyl CoA
D) all of these

Question 43

How many high-energy phosphate bonds are cleaved during the activation of the β-oxidation of fatty acids?

A) 0
B) 1
C) 2
D) 3

Question 44

Which of the following compounds is consumed in the process of converting glycerol to dihydroxyacetone phosphate?

A) ATP
B) NAD⁺
C) both ATP and NAD⁺
D) neither ATP nor NAD⁺

Question 45

Identify the oxidizing agent that is utilized in the first oxidation step of β-oxidation of fatty acids.

A) FAD
B) FADH₂
C) NAD⁺
D) NADH + H⁺

Question 46

Which of the following compounds is consumed in the process of converting glycerol to dihydroxyacetone phosphate?

A) ADP
B) NADH
C) both ADP and NADH
D) neither ADP nor NADH

Question 47

What is the role of acyl-CoA dehydrogenase in the β-oxidation of saturated fatty acids?

A) It eliminates the C2 fragment of fatty acids.
B) It assists in the formation of a cis double bond between the α- and β-carbon atoms.
C) It assists in the formation of a trans double bond between the α- and β-carbon atoms.
D) None of these are the roles of acyl-CoA dehydrogenase.

Question 48

How many ATP molecules are produced for each NADH + H⁺ through the electron transport route that operates in muscle and nerve cells?

A) 1
B) 1.5
C) 2.5
D) 4

Question 49

Which of the following is the first product formed during glycerol catabolism?

A) glycerol 1-phosphate
B) glycerol 2-phosphate
C) glycerol 1,2-bisphosphate
D) glycerol 1,3-bisphosphate

Question 50

Identify the process in which glycogen is broken down into glucose.

A) gluconeogenesis
B) glycogenesis
C) glycogenolysis
D) none of these

Question 51

How many ATP molecules are produced as a result of the complete metabolism of one molecule of glucose in skeletal muscles?

A) 4
B) 6
C) 24
D) 30

Question 52

What is the role of the enzyme enoyl-CoA hydratase in the β-oxidation of saturated fatty acids?

A) It adds a hydroxyl group on the α-carbon of the fatty acid.
B) It adds a hydroxyl group on the β-carbon of the fatty acid.
C) It adds hydroxyl groups on both the α- and β-carbons of the fatty acid.
D) It adds hydrogen atoms on both the α- and β-carbons of the fatty acid.

Question 53

How many ATP molecules are produced for each NADH + H⁺ through the electron transport route that operates in the heart and the liver?

A) 1
B) 1.5
C) 2.5
D) 4

Question 54

How many molecules of ATP are produced during the conversion of two molecules of 1,3-bisphosphoglycerate to yield two molecules of pyruvate?

A) 2
B) 4
C) 6
D) 12

Question 55

Depending on the location of metabolism, how many molecules of ATP are produced from the hydrolysis of a glycerol molecule?

A) 3 to 6
B) 6 to 9
C) 12.5 to 15.5
D) 16.5 to 18.5

Question 56

How many ATP molecules are produced as a result of the complete metabolism of one molecule of glucose in the heart or liver?

A) 12
B) 24
C) 36
D) 32

Question 57

How many molecules of ATP are produced during the oxidative phosphorylation of two molecules of glyceraldehyde 3-phosphate?

A) 8
B) 5
C) 7
D) 12

Question 58

Which of the following chemical solutions must be provided intravenously to combat acidosis during cardiac arrest?

A) 5% carbonate solution
B) 8.4% bicarbonate solution
C) 10.5% acetate solution
D) 4% chloride solution

Question 59

How many molecules of ATP are produced during the oxidative decarboxylation of two molecules of pyruvate to yield two molecules of acetyl CoA?

A) 2
B) 4
C) 6
D) 12

Question 60

Which of the following carbohydrates cannot enter the glycolytic pathway?

A) fructose
B) galactose
C) glycogen
D) none of these

Question 61

Which of the following statements is true of the urea cycle?

A) It generates molecules that can enter the common metabolic pathway.
B) It removes the NH₄⁺ that is produced during oxidative deamination.
C) Both these statements are true.
D) Neither of these statements is true.

Question 62

Identify the reactants of an oxidative deamination reaction.

A) α-ketoglutarate, NAD⁺, and H₂O
B) α-ketoglutarate, NADH, and H⁺
C) glutamate, NAD^+, and H₂O
D) glutamate, NADH, and H⁺

Question 63

To which of the following types of reaction does the formation of acetone from acetoacetate belong?

A) decarboxylation
B) hydrolysis
C) reduction
D) oxidation

Question 64

What is the role of the enzyme hydroxyacyl-CoA dehydrogenase in the β-oxidation of saturated fatty acids?

A) It converts an α-hydroxyacyl-CoA to an α-ketoacyl-CoA.
B) It converts a β-hydroxyacyl-CoA to a β-ketoacyl-CoA.
C) Both of these are the functions of hydroxyacyl-CoA dehydrogenase.
D) Neither of these is the function of hydroxyacyl-CoA dehydrogenase.

Question 65

How many molecules of ATP are produced from the complete metabolism of a molecule of stearic acid?

A) 120
B) 130
C) 240
D) 250

Question 66

What is the effect of the accumulation of ketone bodies in the blood?

A) It leads to a decrease in the concentration of Na+ in the interstitial fluids.
B) It leads to an increase in the pH of the blood.
C) Both of these are the effects of the accumulation of ketone bodies in the blood.
D) Neither of these is the effect of the accumulation of ketone bodies in the blood.

Question 67

Identify an oxidizing agent that is utilized in the second oxidation step of the β-oxidation of fatty acids.

A) FAD
B) FADH²
C) NAD⁺
D) NADH + H⁺

Question 68

To which of the following types of reaction does the formation of β-hydroxybutyrate from acetoacetate belong?

A) decarboxylation
B) hydrolysis
C) reduction
D) oxidation

Question 69

In which of the following organelles does the formation of carbamoyl phosphate occur?

A) the nucleus
B) the mitochondrion
C) both the nucleus and mitochondrion
D) neither the nucleus nor mitochondrion

Question 70

What is the effect of the accumulation of ketone bodies in the blood?

A) It lowers the blood pH.
B) It suppresses insulin secretion.
C) It increases the blood pH.
D) It enhances insulin secretion.

Question 71

Complete metabolism of which of the following fatty acids will yield the highest number of ATP molecules?

A) CH₃(CH₂)₁₂COOH
B) CH₃(CH₂)₁₄COOH
C) CH₃(CH₂)₁₆COOH
D) All of these fatty acids yield the same number of ATP molecules.

Question 72

Which of the following statements is true of the complete metabolism of a molecule of stearic acid?

A) It yields eight FADH², five NAD⁺, and nine molecules of acetyl CoA.
B) It yields five FADH² and five molecules of acetyl CoA.
C) It yields eight FADH², eight NADH + H⁺, and nine molecules of acetyl CoA.
D) It yields five NAD⁺ and five molecules of acetyl CoA.

Question 73

What is the fate of NADH + H⁺ produced during the catabolism of amino acids?

A) It enters the citric acid cycle.
B) It enters the glycolytic pathway.
C) It enters the urea cycle.
D) It enters the oxidative phosphorylation pathway.

Question 74

Which of the following enzymes is associated with the cleavage of β-ketoacyl-CoA?

A) acyl-CoA dehydrogenase
B) hydratase
C) hydroxyacyl-CoA dehydrogenase
D) thiolase

Question 75

Which of the following is a reactant in transamination?

A) α-ketoglutarate
B) β-ketoglutarate
C) glutamate
D) none of these

Question 76

How does the fatty acyl-CoA produced at the end of one turn of the β-oxidation cycle differ from the parent fatty acyl-CoA molecule?

A) It is two carbon atoms shorter than the parent molecule.
B) It is half the size of the parent molecule.
C) It is two carbon atoms longer than the parent molecule.
D) It is an enantiomer of the parent molecule.

Question 77

How does the body respond to excess amino acids?

A) The body catabolizes them for energy production.
B) The body stores them as carbohydrates.
C) The body converts them to keratin.
D) The body excretes them through urine.

Question 78

Which of the following statements is true of the β-oxidation of an unsaturated fatty acid?

A) It is identical to the β-oxidation of a saturated fatty acid.
B) It involves an extra step to convert a cis double bond to a trans double bond.
C) It involves an extra step to convert a trans double bond to a cis double bond.
D) It is completely different from the β-oxidation of a saturated fatty acid.

Question 79

What is the role of α-ketoglutarate in both transamination and oxidative deamination?

A) It is a common product of both transamination and oxidative deamination.
B) It is a common reactant in both transamination and oxidative deamination.
C) It is a reactant in oxidative deamination and a product in transamination.
D) It is a reactant in transamination and a product in oxidative deamination.

Question 80

Which of the following statements is true of a diet that provides an adequate amount of dietary sugar?

A) It enhances the oxidation of fatty acids.
B) It has no effect on the oxidation of fatty acids.
C) It inhibits the oxidation of fatty acids.
D) It enhances the mobilization of fatty acids.