Deck 27: Bioenergetics: How the Body Converts Food to Energy

Question 1

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 reticulum

Answer 1

C

Question 2

What is the technical name given to the baffles of the mitochondria?

A) baffle
B) cristae
C) intermembrane space
D) matrix

Answer 2

B

Question 3

Enzymes associated with which of the following are localized on the cristae?

A) the citric acid cycle
B) oxidative phosphorylation
C) both a and b
D) neither a nor b

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 reticulum

Question 5

In the molecules AMP, ADP and ATP, "A" stands for which of the following?

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

Question 6

Of the compounds classified as carbohydrates, lipids, and proteins, which can be used by the body as fuels?

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

Question 7

Which of the following is true of anabolism?

A) It is endothermic.
B) It is exothermic.
C) It can be either endothermic or exothermic.
D) It is neither endothermic nor exothermic.

Question 8

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

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

Question 9

Which of the following is true of the catabolic pathways for carbohydrates, lipids and proteins?

A) Each type of compound has its own distinct pathway.
B) Carbohydrates and lipids share a common pathway.
C) Carbohydrates and proteins share a common pathway.
D) Lipids and proteins share a common pathway.

Question 10

Which part of metabolism involves the synthesis of molecules?

A) anabolism
B) catabolism
C) both a and b
D) neither a and b

Question 11

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

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

Question 12

How many distinct parts are there in the common metabolic pathway?

A) 1
B) 2
C) 3
D) 4

Question 13

Metabolism is which of the following?

A) all the processes that involve breaking down molecules into smaller fragments
B) all the processes that involve the synthesis of molecules
C) all the processes involved in both a and b above
D) all the processes involved in both a and b plus additional processes

Question 14

Where in the cell are the enzymes that catalyze the common metabolic pathway synthesized?

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

Question 15

Which of the following scientists proposed the baffle model of the mitochondria?

A) R. Franklin
B) H. Krebs
C) G. Palade
D) L. Pauling

Question 16

Enzymes associated with which of the following are localized in the mitochondrial matrix?

A) the citric acid cycle
B) oxidative phosphorylation
C) both a and b
D) neither a nor b

Question 17

The citric acid cycle includes which of the following?

A) the electron transport chain
B) the oxidative phosphorylation pathway
C) both a and b
D) neither a nor b

Question 18

Which sugar is found in AMP, ADP and ATP?

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

Question 19

Mitochondria have how many membranes?

A) 0
B) 1
C) 2
D) 4

Question 20

Which of the following scientists established the relationships among the components of the citric acid cycle?

A) R. Franklin
B) H.Krebs
C) G. Palade
D) L. Pauling

Question 21

In what form is hydrogen transported by the NAD⁺/NADH system?

A) H
B) H⁺
C) H₂
D) H₂O

Question 22

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

A) 1 second
B) 1 minute
C) 1 hour
D) 1 day

Question 23

In what form is hydrogen transported by the FAD/FADH₂ system?

A) H
B) H⁺
C) H₂
D) H₂O

Question 24

Approximately how much energy is released by the hydrolysis of one mole of ATP to AMP?

A) 3.4 kcal
B) 7.3 kcal
C) 10.7 kcal
D) 14.6 kcal

Question 25

In AMP, ADP and ATP the phosphate is linked to ribose through which carbon atom?

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

Question 26

Approximately how much energy is released by the hydrolysis of one mole of AMP?

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

Question 27

Approximately how much ATP does a human manufacture and degrade in a day?

A) 10 kg
B) 20 kg
C) 40 kg
D) 80 kg

Question 28

In AMP, ADP and ATP, what type of linkage connects the phosphate to the sugar?

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

Question 29

Which of the following is true of the FAD/FADH₂ system?

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 30

Which of the molecules AMP, ADP and ATP contain high energy phosphoric anhydride bonds?

A) ADP and AMP
B) ADP and ATP
C) AMP and ATP
D) all of them

Question 31

Which atom of NAD⁺ carries the positive charge?

A) C
B) N
C) O
D) P

Question 32

In ADP and ATP, what type of linkage connects the phosphate atoms?

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

Question 33

Approximately what percentage of the total caloric content of food is the human body able to extract?

A) 10 to 30%
B) 40 to 60%
C) 50-70%
D) 70-90%

Question 34

Which of the following is poorest for storing or releasing energy?

A) ADP
B) AMP
C) ATP
D) None, they are all equally good.

Question 35

The NAD⁺/NAD and FAD/FADH₂ systems transport which of the following?

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

Question 36

Approximately how much energy is released by the hydrolysis of one mole of ATP to ADP?

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

Question 37

Approximately how much energy is released by the hydrolysis of one mole of ADP to AMP?

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

Question 38

Which of the following correctly describes the composition of NAD⁺?

A) adenine, nicotinamide, a ribose and a ribitol linked by a diphosphate
B) adenine, nicotinamide, and two ribose molecules linked by a diphosphate
C) adenine, nicotinamide, and two ribose molecules linked by a triphosphate
D) adenine, nicotinamide, and two ribitol molecules linked by a diphosphate

Question 39

In AMP, ADP and ATP the adenine is linked to ribose through which carbon atom?

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

Question 40

Which of the following correctly describes the composition of FAD?

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

Question 41

The conversion of citrate to isocitrate in step 2 of the citric acid cycle involves which of the following sequences of reactions?

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

Question 42

Step 3 of the citric acid cycle involves the conversion of isocitrate to α-ketoglutarate. What is the intermediate species formed in this step?

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

Question 43

Which of the following is the oxidizing agent in the reaction which converts isocitrate to oxalosuccinate?

A) isocitrate
B) NAD⁺
C) NADH
D) FAD

Question 44

What type of reaction occurs when α-ketoglutarate is converted to succinate in steps 4 and 5 of the citric acid cycle?

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

Question 45

The citric acid cycle involves how many distinct steps?

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

Question 46

The formation of citrate ion in step 1 of the citric acid cycle involves the reaction of acetyl CoA with which of the following?

A) isocitrate
B) oxaloacetate
C) fumarate
D) malate

Question 47

Which of the following is the source of the carbon atom in the CO₂ produced when oxalosuccinate is converted to α-ketoglutarate in step 3 of the citric acid cycle?

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

Question 48

Which of the following species, all of which are involved in step 2 of the citric acid cycle, is optically active?

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

Question 49

Which of the following correctly describes the chemical reactivity of citrate and isocitrate?

A) Both citrate and isocitrate can be oxidized.
B) Neither citrate nor isocitrate can be oxidized.
C) Citrate can be oxidized, but isocitrate cannot.
D) Isocitrate can be oxidized, but citrate cannot.

Question 50

Pantothenic acid forms which of the following linkages when it is part of CoA?

A) an ester linkage to diphosphate and an amide linkage to ethylamine
B) an ester linkage to diphosphate and an amide linkage to diethylamine
C) an ester linkage to diphosphate and an amide linkage to mercapto- ethylamine
D) an ester linkage to diphosphate and an amide linkage to triethylamine

Question 51

Which of the following is an intermediate in the conversion of citrate to isocitrate?

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

Question 52

What type of reaction occurs when oxalosuccinate is converted to α-ketoglutarate in step 3 of the citric acid cycle?

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

Question 53

The catabolism of carbohydrates or lipids produces smaller species which then enter the citric acid cycle. How many carbon atoms are in these smaller species?

A) 1
B) 2
C) 3
D) 4

Question 54

What type of reaction occurs when isocitrate is converted to oxalosuccinate in step 3 of the citric acid cycle?

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

Question 55

Which of the following functional groups is not found in pantothenic acid?

A) amide
B) amine
C) primary alcohol
D) secondary alcohol

Question 56

The catabolism of proteins produces smaller species which then enter the citric acid cycle. How many carbon atoms are in these smaller species?

A) 1
B) 2
C) 4
D) either 2 or 4

Question 57

Which of the following correctly describes citrate and isocitrate?

A) They are both secondary alcohols.
B) They are both tertiary alcohols.
C) Citrate is a secondary alcohol, but isocitrate is a tertiary alcohol.
D) Citrate is a tertiary alcohol, but isocitrate is a secondary alcohol.

Question 58

The conversion of isocitrate to α-ketoglutarate in step 3 of the citric acid cycle involves which of the following sequences of reactions?

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

Question 59

What type of reaction occurs when citryl CoA is converted to citrate in step 1 of the citric acid cycle?

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

Question 60

Which of the following species is transported by CoA?

A) CH₃O−
B) CH₃CO−
C) CH₃COO−
D) C₂H₃O₂−

Question 61

What type of reaction occurs when fumarate is converted to malate in step 7 of the citric acid cycle?

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

Question 62

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

Question 63

How many molecules of NADH are produced by one pass through the citric acid cycle?

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

Question 64

The citric acid cycle is inhibited by the accumulation of which of the following?

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

Question 65

How many electrons are consumed when H⁺ and O₂ combine to produce two molecules of water?

A) 1
B) 2
C) 3
D) 4

Question 66

Approximately how many subunits make up complex I of the electron and H⁺ transport chain?

A) 20
B) 40
C) 60
D) 80

Question 67

Ubiquinone is also known as which of the following?

A) acetyl CoA
B) CoA
C) CoQ
D) CoU

Question 68

How many molecules of FADH₂ are produced by one pass through the citric acid cycle?

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

Question 69

Complex I of the electron and H⁺ transport chain contains a number of clusters made up of a metal and a nonmetal. Which atoms are found in these clusters?

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

Question 70

Which of the following is the oxidizing agent in the reaction which converts succinate to fumarate?

A) FAD
B) FADH₂
C) NAD⁺
D) succinate

Question 71

How many different complexes are involved in the electron and H⁺ transport chain?

A) 1
B) 2
C) 3
D) 4

Question 72

How many molecules of CO₂ are produced by one pass through the citric acid cycle?

A) 1
B) 2
C) 3
D) 4

Question 73

Which portions of the citric acid cycle produce most of the energy generated by the cycle?

A) formation of GTP
B) hydrolysis of GDP
C) oxidation of FADH₂ and NADH
D) reduction of FAD and NAD⁺

Question 74

What type of reaction occurs when malate is converted to oxaloacetate in step 8 of the citric acid cycle?

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

Question 75

Which of the following is true when H⁺ and O₂ combine to produce two molecules of water?

A) Two electrons are consumed and the reaction is endothermic.
B) Two electrons are consumed and the reaction is exothermic.
C) Four electrons are consumed and the reaction is endothermic.
D) Four electrons are consumed and the reaction is exothermic.

Question 76

Which of the following is the oxidizing agent in the reaction which converts malate to oxaloacetate?

A) FAD
B) FADH₂
C) NAD⁺
D) NADH

Question 77

Which complex is the largest of the complexes involved in the electron and H⁺ transport chain?

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

Question 78

Where are the enzymes which promote the reaction 4H⁺ + 4e− + O₂ → 2H₂O located?

A) in the cytoplasm
B) embedded in the inner membrane of the mitochondria
C) embedded in the outer membrane of the mitochondria
D) embedded in the matrix

Question 79

Which of the following stimulates the enzyme isocitrate dehydrogenase?

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

Question 80

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

A) Ca
B) Co
C) Fe
D) Mg