Deck 26: Bioenergetics: How the Body Converts Food to Energy

Question 1

Which of the following statements is true of anabolic reactions?

A) They provide the energy needed by cells.
B) They synthesize the compounds needed by cells.
C) They provide the energy needed by cells and they synthesize the compounds needed by cells.
D) None of these

Answer 1

B

Question 2

Which part of the cell contains enzymes that catalyze the common metabolic pathways?

A) the cytosol
B) the Golgi bodies
C) the mitochondria
D) the nucleus

Answer 2

C

Question 3

Which part of a mitochondrion contains the enzymes that catalyze the citric acid cycle?

A) inner mitochondrial membrane
B) matrix
C) outer mitochondrial membrane
D) They are present throughout a mitochondrion.

Answer 3

B

Question 4

Which of the following organelles package and process proteins for secretion and delivery to other cellular compartments?

A) Golgi bodies
B) lysosomes
C) mitochondria
D) smooth endoplasmic reticuli

Question 5

Which of the following bonds is found between adenine and ribose in an ATP molecule?

A) a β-N-glycosidic bond
B) a β-N-fructosidic bond
C) an α-N-glycosidic bond
D) an α-N-fructosidic bond

Question 6

Which of the following classes of biological compounds can be used by the body as fuel?

A) only carbohydrates and lipids
B) only carbohydrates and proteins
C) only lipids and proteins
D) all of these

Question 7

Which of the following organelles remove damaged cellular materials and foreign materials from cells?

A) Golgi bodies
B) lysosomes
C) mitochondria
D) smooth endoplasmic reticuli

Question 8

Which of the following statements is true of the energy-conversion pathways for carbohydrates, lipids, and proteins?

A) Each of these compounds have their own energy-conversion pathways.
B) Carbohydrates and lipids share a common energy-conversion pathway.
C) Carbohydrates and proteins share a common energy-conversion pathway.
D) Lipids and proteins share a common energy-conversion pathway.

Question 9

Which part of the mitochondrion consists of baffle-like structures?

A) the outer mitochondrial membrane
B) the cristae
C) the intermembrane space
D) the matrix

Question 10

Identify a sugar that is present in the nucleotides AMP, ADP, and ATP.

A) fructose
B) galactose
C) glucose
D) ribose

Question 11

In the abbreviations AMP, ADP, and ATP, what does "A" stand for?

A) the alkaloid atropine
B) the amino acid alanine
C) the amino acid arginine
D) the nucleoside adenosine

Question 12

Identify a metabolic pathway associated with the enzymes localized on the mitochondrial cristae.

A) the citric acid cycle
B) the electron transport chain
C) the citric acid cycle and the electron transport chain
D) none of these

Question 13

Identify a metabolic pathway associated with the enzymes localized in the mitochondrial matrix.

A) the citric acid cycle
B) the oxidative phosphorylation pathway
C) the citric acid cycle and the oxidative phosphorylation pathway
D) none of these

Question 14

Which of the following pathways converge to a common catabolic pathway?

A) only the pathways for the catabolism of carbohydrates and lipids
B) only the pathways for the catabolism of carbohydrates and proteins
C) only the pathways for the catabolism of lipids and proteins
D) the pathways for the catabolism of proteins, carbohydrates, and lipids

Question 15

Which types of metabolic reactions are involved in the synthesis of molecules?

A) anabolic reactions
B) catabolic reactions
C) anabolic and catabolic reactions
D) none of these

Question 16

In which of the following organelles does the common catabolic pathway take place in higher organisms?

A) Golgi bodies
B) lysosomes
C) mitochondria
D) smooth endoplasmic reticuli

Question 17

Which of the following statements is true of metabolism?

A) It is the sum of all the processes involved in the breaking down of complex biomolecules.
B) It is the sum of all the processes involved in the synthesis of biomolecules.
C) It is the sum of all the processes involved in the breaking down of complex biomolecules and in the synthesis of biomolecules.
D) None of these

Question 18

Which of the following pathways is a part of the common catabolic pathway?

A) the citric acid cycle
B) the oxidative phosphorylation pathway
C) the citric acid cycle and the oxidative phosphorylation pathway
D) none of these

Question 19

Which of the following statements is true of a mitochondrion?

A) It is single-membraned organelle.
B) It is double-membraned organelle.
C) It is triple-membraned organelle.
D) It does not have a membrane.

Question 20

Which part of the mitochondria contains the enzymes associated with the citric acid cycle?

A) the outer mitochondrial membrane
B) the matrix
C) the intermembrane space
D) the inner mitochondrial membrane

Question 21

Identify the operative part of the coenzyme NAD⁺.

A) adenine
B) ribose
C) nicotinamide
D) flavin

Question 22

In AMP, ADP, and ATP, which type of linkage connects a phosphate group with the ribose sugar?

A) an anhydride linkage
B) an ester linkage
C) an ether linkage
D) none of these

Question 23

Identify the final principal compound in the common catabolic pathway.

A) coenzyme A
B) acetate
C) riboflavin
D) nicotinamide

Question 24

How is an acetyl group linked to a CoA molecule?

A) by a phosphodiester bond
B) by a thioester bond
C) by an ether bond
D) by an anhydride bond

Question 25

Which components of NAD⁺ are linked to each other by a diphosphate bond?

A) adenine, a ribose sugar, and a ribitol molecule
B) adenosine diphosphate and a ribose sugar
C) nicotinamide and two ribose sugars
D) adenosine diphosphate, nicotinamide, and two ribitol molecules

Question 26

How is a phosphate group linked to the ribose sugar in an ATP molecule?

A) by three phosphoric ester bonds
B) by a phosphoric anhydride bond
C) by three phosphoric anhydride bonds
D) by a phosphoric ester bond

Question 27

How much energy is released during the hydrolysis of a phosphoric ester bond?

A) 3.4 kcal/mol
B) 7.3 kcal/mol
C) 10.7 kcal/mol
D) 18 kcal/mol

Question 28

Identify the molecules that contain high-energy phosphoric anhydride bonds.

A) both ADP and AMP
B) both ADP and ATP
C) both AMP and ATP
D) all of these

Question 29

What is the approximate lifetime of an ATP molecule in a cell?

A) one second
B) one minute
C) one hour
D) one day

Question 30

Which of the following is a component of coenzyme A?

A) nicotinamide
B) pantothenic acid
C) ribitol
D) deoxyribose

Question 31

Which is the operative part of the coenzyme FAD?

A) ribitol
B) ribose sugar
C) flavin
D) phosphate group

Question 32

Which of the following nucleotides releases the least energy on hydrolysis?

A) ADP
B) AMP
C) ATP
D) All of these release equal amounts of energy.

Question 33

In AMP, ADP, and ATP, which carbon of the ribose sugar is bonded to the adenine molecule?

A) carbon 1
B) carbon 2
C) carbon 3
D) carbon 5

Question 34

Which of the following nucleotides releases the maximum energy on hydrolysis?

A) ATP
B) ADP
C) AMP
D) All of these release equal amounts of energy.

Question 35

Which of the following statements is true of FAD and FADH₂?

A) FAD is the oxidized form, and FADH₂ is the reduced form.
B) FAD is the reduced form, and FADH₂ is the oxidized form.
C) The conversion of FAD to FADH₂ is an addition reaction.
D) The conversion of FAD to FADH₂ is a condensation reaction.

Question 36

How much energy is released during the hydrolysis of a phosphoric anhydride bond?

A) 3.4 kcal/mol
B) 7.3 kcal/mol
C) 10.7 kcal/mol
D) 18 kcal/mol

Question 37

Which of the following is the correct composition of an FAD coenzyme?

A) adenine, flavin, a ribose sugar, and a ribitol molecule linked by a diphosphate bond
B) adenine, flavin, and two ribose sugars linked by a diphosphate bond
C) adenine, flavin, and two ribose sugars linked by a triphosphate bond
D) adenine, flavin, and two ribitol molecules linked by a diphosphate bond

Question 38

Which type of linkage is present between any two phosphate groups in ATP?

A) an anhydride linkage
B) an ester linkage
C) an ether linkage
D) none of these

Question 39

Which of the following species are transported by NAD⁺ and FAD coenzymes?

A) electrons
B) hydrogen ions
C) both electrons and hydrogen ions
D) neither electrons nor hydrogen ions

Question 40

In AMP, ADP, and ATP, which carbon of the ribose sugar is bonded to a phosphate group?

A) carbon 1
B) carbon 2
C) carbon 3
D) carbon 5

Question 41

Which of the following linkages does pantothenic acid form in a CoA molecule?

A) an ester linkage with diphosphate and an amide linkage with ethylamine
B) an ester linkage with diphosphate and an amide linkage with diethylamine
C) an ester linkage with diphosphate and an amide linkage with mercaptoethylamine
D) an ester linkage with diphosphate and an amide linkage with a tertiary amine

Question 42

How many distinct steps does the citric acid cycle contain?

A) 4
B) 6
C) 8
D) 10

Question 43

Which of the following sequences of reactions occurs during the conversion of isocitrate to α-ketoglutarate?

A) decarboxylation followed by oxidation
B) decarboxylation followed by reduction
C) oxidation followed by decarboxylation
D) reduction followed by decarboxylation

Question 44

Which of the following is the correct sequence of reactions that occur during the conversion of citrate to isocitrate?

A) dehydration followed by hydration
B) hydration followed by dehydration
C) oxidation followed by reduction
D) reduction followed by oxidation

Question 45

During step 1 of the citric acid cycle, which of the following reactions occurs during the conversion of citryl CoA to citrate?

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

Question 46

Which of the following reactions occurs during the conversion of α-ketoglutarate to succinate in the citric acid cycle?

A) oxidative carboxylation
B) oxidative decarboxylation
C) reductive carboxylation
D) reductive decarboxylation

Question 47

Which of the following reactions occurs during the conversion of isocitrate to oxalosuccinate in the citric acid cycle?

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

Question 48

Which of the following compounds is an intermediate formed during the conversion of isocitrate to α-ketoglutarate?

A) fumarate
B) oxaloacetate
C) oxalosuccinate
D) succinate

Question 49

In the citric acid cycle, which of the following reactions occurs during the conversion of oxalosuccinate to α-ketoglutarate?

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

Question 50

Which of the following compounds is an intermediate formed during the conversion of citrate to isocitrate?

A) cis-aconitate
B) trans-aconitate
C) fumarate
D) malate

Question 51

Which of the following coenzymes helps oxidize isocitrate to oxalosuccinate?

A) FADH₂
B) NAD⁺
C) NADH
D) FAD

Question 52

Which of the following statements is true of the structure of CoA?

A) It has a guanine molecule.
B) It has a phosphotriester bond.
C) It has a mercaptoethylamine molecule.
D) It has a deoxyribose sugar.

Question 53

During step 1 of the citric acid cycle, which of the following substrates react to form a citrate ion?

A) isocitrate and oxaloacetate
B) oxaloacetate and acetyl CoA
C) fumarate and acetyl CoA
D) malate and isocitrate

Question 54

Which of the following species is transported by CoA?

A) CH₃O⁻
B) CH₃CO⁻
C) CH₃COO⁻
D) C₂H₅O₂⁻

Question 55

Which statement best compares the chemical structure of citrate and isocitrate?

A) Both have secondary alcohol groups.
B) Both have tertiary alcohol groups.
C) Citrate has a secondary alcohol group, whereas isocitrate has a tertiary alcohol group.
D) Citrate has a tertiary alcohol group, whereas isocitrate has a secondary alcohol group.

Question 56

Which of the following species of the citric acid cycle is optically active?

A) cis-aconitate
B) citrate
C) isocitrate
D) none of these

Question 57

Which of the following species is the source of CO₂ that is produced during the conversion of oxalosuccinate to α-ketoglutarate?

A) acetyl CoA
B) oxaloacetate
C) succinate
D) none of these

Question 58

Which of the following sets of reagents is required for the conversion of α-ketoglutarate to succinate in steps 4 and 5 of the citric acid cycle?

A) NAD⁺, GDP, and inorganic phosphate
B) NAD⁺, GTP, inorganic phosphate, and water
C) NAD⁺, GTP, and inorganic phosphate
D) NAD⁺, GDP, inorganic phosphate, and water

Question 59

Which of the following is the starting compound of the citric acid cycle?

A) acetyl CoA
B) oxaloacetate
C) isocitrate
D) succinyl CoA

Question 60

Which statement best compares the reactions of citrate and isocitrate in the citric acid cycle?

A) Both citrate and isocitrate are oxidized in the citric acid cycle.
B) Neither citrate nor isocitrate is oxidized in the citric acid cycle.
C) Citrate is oxidized, whereas isocitrate is not oxidized in the citric acid cycle.
D) Isocitrate is oxidized, whereas citrate is not oxidized in the citric acid cycle.

Question 61

What is the function of CoQ in complex I of the electron and H⁺ transport chain?

A) It oxidizes FADH₂ to FAD.
B) It oxidizes NADH to NAD⁺.
C) It reduces FAD to FADH₂.
D) It reduces NAD⁺ to NADH.

Question 62

Which part of a mitochondrion contains the enzymes that catalyze the following exothermic reaction: 4H⁺ + 4e⁻ + O₂ → 2H₂O?

A) the intermembrane space
B) the inner membrane
C) the outer membrane
D) the matrix

Question 63

Which of the following coenzymes helps oxidize succinate to fumarate?

A) FAD
B) FADH₂
C) NAD⁺
D) NADH

Question 64

Which of the following coenzymes helps oxidize malate to oxaloacetate?

A) FAD
B) FADH₂
C) NAD⁺
D) NADH

Question 65

How many molecules of NADH are produced at the end of the citric acid cycle?

A) zero
B) one
C) two
D) three

Question 66

The reaction between NADH and CoQ releases some energy. How is this energy used in a cell?

A) It is used to transport electrons from the intermembrane space to the matrix of mitochondria.
B) It is used to transport electrons from the matrix to the intermembrane space of the mitochondria.
C) It is used to transport protons from the intermembrane space to the matrix of mitochondria.
D) It is used to transport protons from the matrix to the intermembrane space of the mitochondria.

Question 67

The reduced coenzymes NADH and FADH2 provide hydrogen ions and electrons for the following reaction: 4H⁺ + 4e⁻ + O₂ → 2H₂O. Which of the following statements is true of this reaction?

A) It is an endothermic reaction wherein two electrons are consumed.
B) It is an exothermic reaction wherein two electrons are consumed.
C) It is an endothermic reaction wherein four electrons are consumed.
D) It is an exothermic reaction wherein four electrons are consumed.

Question 68

How many molecules of CO₂ are released at the end of the citric acid cycle?

A) one
B) two
C) three
D) four

Question 69

In the citric acid cycle, which of the following reactions occurs during the conversion of fumarate to malate?

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

Question 70

Which of the following reactions in the citric acid cycle produces the most energy?

A) the formation of GTP
B) the hydrolysis of GDP
C) the oxidation of FADH₂
D) the reduction of NAD⁺

Question 71

How many molecules of FADH₂ are produced at the end of the citric acid cycle?

A) zero
B) one
C) two
D) three

Question 72

Which of the following elements is found in complex I of the electron and H⁺ transport chain?

A) calcium
B) cobalt
C) iron
D) magnesium

Question 73

What is the symbolic representation of ubiquinone?

A) FeS
B) CoA
C) CoQ
D) FAD

Question 74

Complex I of the electron and H⁺ transport chain contains a number of clusters that contain a metal and a nonmetal. Which of the following elements are found in these clusters?

A) iron and nitrogen
B) iron and sulfur
C) magnesium and nitrogen
D) magnesium and sulfur

Question 75

Which of the following coenzymes inhibit the enzymes of the citric acid cycle when they accumulate in excess?

A) ATP and NADH + H⁺
B) ADP and NAD⁺
C) FADH₂ and NAD⁺
D) none of these

Question 76

In the citric acid cycle, which of the following reactions occurs during the conversion of fumarate to malate?

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

Question 77

Which of the following elements is found in complex II of the electron and H⁺ transport chain?

A) calcium
B) cobalt
C) iron
D) none of these

Question 78

Which of the following compounds stimulates the enzyme isocitrate dehydrogenase?

A) ATP and NADH + H⁺
B) ADP and NAD⁺
C) acetyl CoA
D) none of these

Question 79

What is the minimum number of protons required for the overall oxidation process to occur in the electron transport chain?

A) one
B) two
C) four
D) eight

Question 80

Which of the following is the largest complex of the electron and H⁺ transport chain?

A) complex I
B) complex II
C) complex III
D) complex IV