Deck 9: Cellular Respiration: Harvesting Chemical Energy

Question 1

When a molecule of NAD+ (nicotinamide adenine dinucleotide)gains a hydrogen atom (not a hydrogen ion)the molecule becomes

A)hydrogenated.
B)oxidized.
C)reduced.
D)redoxed.
E)a reducing agent.

Answer 1

C

Question 2

Refer to Figure 9.1 to answer the following questions.
Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

In which reaction does an intermediate pathway become oxidized?

Answer 2

C

Question 3

Refer to Figure 9.1 to answer the following questions.
Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

Which step shows a split of one molecule into two smaller molecules?

Answer 3

B

Question 4

What is the term for metabolic pathways that release stored energy by breaking down complex molecules?

A)anabolic pathways
B)catabolic pathways
C)fermentation pathways
D)thermodynamic pathways
E)bioenergetic pathways

Question 5

Which of the following statements describes the results of this reaction?
C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + Energy

A)C₆H₁₂O₆ is oxidized and O₂ is reduced.
B)O₂ is oxidized and H₂O is reduced.
C)CO₂ is reduced and O₂ is oxidized.
D)C₆H₁₂O₆ is reduced and CO₂ is oxidized.
E)O₂ is reduced and CO₂ is oxidized.

Question 6

Refer to Figure 9.1 to answer the following questions.
Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed during glycolysis?

A)0%
B)2%
C)10%
D)38%
E)100%

Question 7

The ATP made during glycolysis is generated by

A)substrate-level phosphorylation.
B)electron transport.
C)photophosphorylation.
D)chemiosmosis.
E)oxidation of NADH to NAD⁺.

Question 8

Refer to Figure 9.1 to answer the following questions.
Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

Which step consists of a phosphorylation reaction in which ATP is the phosphate source?

Question 9

Why are carbohydrates and fats considered high energy foods?

A)They have a lot of oxygen atoms.
B)They have no nitrogen in their makeup.
C)They can have very long carbon skeletons.
D)They have a lot of electrons associated with hydrogen.
E)They are easily reduced.

Question 10

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes

A)dehydrogenated.
B)hydrogenated.
C)oxidized.
D)reduced.
E)an oxidizing agent.

Question 11

Refer to Figure 9.1 to answer the following questions.
Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

In which step is an inorganic phosphate added to the reactant?

Question 12

Why does the oxidation of organic compounds by molecular oxygen to produce CO₂ and water release free energy?

A)The covalent bonds in organic molecules are higher energy bonds than those in water and carbon dioxide.
B)Electrons are being moved from atoms that have a lower affinity for electrons (such as C)to atoms with a higher affinity for electrons (such as O).
C)The oxidation of organic compounds can be used to make ATP.
D)The electrons have a higher potential energy when associated with water and CO₂ than they do in organic compounds.
E)The covalent bond in O2 is unstable and easily broken by electrons from organic molecules.

Question 13

The molecule that functions as the reducing agent (electron donor)in a redox or oxidation-reduction reaction

A)gains electrons and gains energy.
B)loses electrons and loses energy.
C)gains electrons and loses energy.
D)loses electrons and gains energy.
E)neither gains nor loses electrons, but gains or loses energy.

Question 14

Refer to Figure 9.1 to answer the following questions.
Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

Which step involves an endergonic reaction?

Question 15

When electrons move closer to a more electronegative atom, what happens?

A)Energy is released.
B)Energy is consumed.
C)The more electronegative atom is reduced.
D)The more electronegative atom is oxidized.
E)A and C are correct.

Question 16

Which process in eukaryotic cells will proceed normally whether oxygen (O₂)is present or absent?

A)electron transport
B)glycolysis
C)the citric acid cycle
D)oxidative phosphorylation
E)chemiosmosis

Question 17

An electron loses potential energy when it

A)shifts to a less electronegative atom.
B)shifts to a more electronegative atom.
C)increases its kinetic energy.
D)increases its activity as an oxidizing agent.
E)attaches itself to NAD⁺.

Question 18

Which of the following statements describes NAD⁺?

A)NAD⁺ is reduced to NADH during both glycolysis and the citric acid cycle.
B)NAD⁺ has more chemical energy than NADH.
C)NAD⁺ is reduced by the action of hydrogenases.
D)NAD⁺ can donate electrons for use in oxidative phosphorylation.
E)In the absence of NAD⁺, glycolysis can still function.

Question 19

Where does glycolysis takes place?

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

Question 20

The oxygen consumed during cellular respiration is involved directly in which process or event?

A)glycolysis
B)accepting electrons at the end of the electron transport chain
C)the citric acid cycle
D)the oxidation of pyruvate to acetyl CoA
E)the phosphorylation of ADP to form ATP

Question 21

Refer to Figure 9.1 to answer the following questions.
Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

During glycolysis, when glucose is catabolized to pyruvate, most of the energy of glucose is

A)transferred to ADP, forming ATP.
B)transferred directly to ATP.
C)retained in the pyruvate.
D)stored in the NADH produced.
E)used to phosphorylate fructose to form fructose-6-phosphate.

Question 22

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Starting with citrate, which of the following combinations of products would result from three turns of the citric acid cycle?

A)1 ATP, 2 CO₂, 3 NADH, and 1 FADH₂
B)2 ATP, 2 CO₂, 1 NADH, and 3 FADH₂
C)3 ATP, 3 CO₂, 3 NADH, and 3 FADH₂
D)3 ATP, 6 CO₂, 9 NADH, and 3 FADH₂
E)38 ATP, 6 CO₂, 3 NADH, and 12 FADH₂

Question 23

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Carbon skeletons for amino acid biosynthesis are supplied by intermediates of the citric acid cycle. Which intermediate would supply the carbon skeleton for synthesis of a five-carbon amino acid?

A)succinate
B)malate
C)citrate
D)α-ketoglutarate
E)isocitrate

Question 24

Refer to Figure 9.1 to answer the following questions.
Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

A molecule that is phosphorylated

A)has been reduced as a result of a redox reaction involving the loss of an inorganic phosphate.
B)has a decreased chemical reactivity; it is less likely to provide energy for cellular work.
C)has been oxidized as a result of a redox reaction involving the gain of an inorganic phosphate.
D)has an increased chemical reactivity; it is primed to do cellular work.
E)has less energy than before its phosphorylation and therefore less energy for cellular work.

Question 25

Use the following information to answer the next questions.
In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric acid cycle. First, however, the pyruvate 1) loses a carbon, which is given off as a molecule of CO2, 2) is oxidized to form a two-carbon compound called acetate, and 3) is bonded to coenzyme A.
How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate?

A)2
B)4
C)6
D)8
E)10

Question 26

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Starting with one molecule of isocitrate and ending with fumarate, what is the maximum number of ATP molecules that could be made through substrate-level phosphorylation?

A)1
B)2
C)11
D)12
E)24

Question 27

Refer to Figure 9.1 to answer the following questions.
Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

In glycolysis, for each molecule of glucose oxidized to pyruvate

A)2 molecules of ATP are used and 2 molecules of ATP are produced.
B)2 molecules of ATP are used and 4 molecules of ATP are produced.
C)4 molecules of ATP are used and 2 molecules of ATP are produced.
D)2 molecules of ATP are used and 6 molecules of ATP are produced.
E)6 molecules of ATP are used and 6 molecules of ATP are produced.

Question 28

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

How many reduced dinucleotides would be produced with four turns of the citric acid cycle?

A)1 FADH₂ and 4 NADH
B)2 FADH₂ and 8 NADH
C)4 FADH₂ and 12 NADH
D)1 FAD and 4 NAD⁺
E)4 FAD⁺ and 12 NAD⁺

Question 29

Refer to Figure 9.1 to answer the following questions.
Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

Starting with one molecule of glucose, the "net" products of glycolysis are

A)2 NAD⁺, 2 H⁺, 2 pyruvate, 2 ATP, and 2 H₂O.
B)2 NADH, 2 H⁺, 2 pyruvate, 2 ATP, and 2 H₂O.
C)2 FADH₂, 2 pyruvate, 4 ATP, and 2 H₂O.
D)6 CO₂, 6 H₂O, 2 ATP, and 2 pyruvate.
E)6 CO₂, 6 H₂O, 36 ATP, and 2 citrate.

Question 30

Use the following information to answer the next questions.
In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric acid cycle. First, however, the pyruvate 1) loses a carbon, which is given off as a molecule of CO2, 2) is oxidized to form a two-carbon compound called acetate, and 3) is bonded to coenzyme A.
Which of the following intermediary metabolites enters the citric acid cycle and is formed, in part, by the removal of a carbon (CO₂)from one molecule of pyruvate?

A)lactate
B)glyceraldehydes-3-phosphate
C)oxaloacetate
D)acetyl CoA
E)citrate

Question 31

Use the following information to answer the next questions.
In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric acid cycle. First, however, the pyruvate 1) loses a carbon, which is given off as a molecule of CO2, 2) is oxidized to form a two-carbon compound called acetate, and 3) is bonded to coenzyme A.
Why is coenzyme A, a sulfur containing molecule derived from a B vitamin, added?

A)because sulfur is needed for the molecule to enter the mitochondrion
B)in order to utilize this portion of a B vitamin which would otherwise be a waste product from another pathway
C)to provide a relatively unstable molecule whose acetyl portion can readily bind to oxaloacetate
D)because it drives the reaction that regenerates NAD⁺
E)in order to remove one molecule of CO₂

Question 32

Refer to Figure 9.1 to answer the following questions.
Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

Why is glycolysis described as having an investment phase and a payoff phase?

A)It both splits molecules and assembles molecules.
B)It attaches and detaches phosphate groups.
C)It uses glucose and generates pyruvate.
D)It shifts molecules from cytosol to mitochondrion.
E)It uses stored ATP and then forms a net increase in ATP.

Question 33

Use the following information to answer the next questions.
In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric acid cycle. First, however, the pyruvate 1) loses a carbon, which is given off as a molecule of CO2, 2) is oxidized to form a two-carbon compound called acetate, and 3) is bonded to coenzyme A.
How does pyruvate enter the mitochondrion?

A)active transport
B)diffusion
C)facilitated diffusion
D)through a channel
E)through a pore

Question 34

Refer to Figure 9.1 to answer the following questions.
Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

Which kind of metabolic poison would most directly interfere with glycolysis?

A)an agent that reacts with oxygen and depletes its concentration in the cell
B)an agent that binds to pyruvate and inactivates it
C)an agent that closely mimics the structure of glucose but is not metabolized
D)an agent that reacts with NADH and oxidizes it to NAD⁺
E)an agent that blocks the passage of electrons along the electron transport chain

Question 35

Use the following information to answer the next questions.
In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric acid cycle. First, however, the pyruvate 1) loses a carbon, which is given off as a molecule of CO2, 2) is oxidized to form a two-carbon compound called acetate, and 3) is bonded to coenzyme A.
These three steps result in the formation of

A)acetyl CoA, O₂, and ATP.
B)acetyl CoA, FADH₂, and CO₂.
C)acetyl CoA, FAD, H₂, and CO₂.
D)acetyl CoA, NADH, H⁺, and CO₂.
E)acetyl CoA, NAD⁺, ATP, and CO₂.

Question 36

Refer to Figure 9.1 to answer the following questions.
Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

The free energy for the oxidation of glucose to CO₂ and water is -686 kcal/mole and the free energy for the reduction of NAD+ to NADH is +53 kcal/mole. Why are only two molecules of NADH formed during glycolysis when it appears that as many as a dozen could be formed?

A)Most of the free energy available from the oxidation of glucose is used in the production of ATP in glycolysis.
B)Glycolysis is a very inefficient reaction, with much of the energy of glucose released as heat.
C)Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis.
D)There is no CO₂ or water produced as products of glycolysis.
E)Glycolysis consists of many enzymatic reactions, each of which extracts some energy from the glucose molecule.

Question 37

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

How many molecules of carbon dioxide (CO₂)would be produced by five turns of the citric acid cycle?

A)2
B)5
C)10
D)12
E)60

Question 38

Refer to Figure 9.1 to answer the following questions.
Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each step is lettered. Use these letters to answer the questions.

In addition to ATP, what are the end products of glycolysis?

A)CO₂ and H₂O
B)CO₂ and pyruvate
C)NADH and pyruvate
D)CO₂ and NADH
E)H₂O, FADH₂, and citrate

Question 39

Use the following information to answer the next questions.
In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric acid cycle. First, however, the pyruvate 1) loses a carbon, which is given off as a molecule of CO2, 2) is oxidized to form a two-carbon compound called acetate, and 3) is bonded to coenzyme A.
During cellular respiration, acetyl CoA accumulates in which location?

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

Question 40

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Carbon dioxide (CO₂)is released during which of the following stages of cellular respiration?

A)glycolysis and the oxidation of pyruvate to acetyl CoA
B)oxidation of pyruvate to acetyl CoA and the citric acid cycle
C)the citric acid cycle and oxidative phosphorylation
D)oxidative phosphorylation and fermentation
E)fermentation and glycolysis

Question 41

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Energy released by the electron transport chain is used to pump H+ ions into which location?

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

Question 42

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Which of the following produces the most ATP when glucose (C₆H₁₂O₆)is completely oxidized to carbon dioxide (CO₂)and water?

A)glycolysis
B)fermentation
C)oxidation of pyruvate to acetyl CoA
D)citric acid cycle
E)oxidative phosphorylation (chemiosmosis)

Question 43

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

During aerobic respiration, electrons travel downhill in which sequence?

A)food → citric acid cycle → ATP → NAD⁺
B)food → NADH → electron transport chain → oxygen
C)glucose → pyruvate → ATP → oxygen
D)glucose → ATP → electron transport chain → NADH
E)food → glycolysis → citric acid cycle → NADH → ATP

Question 44

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

The primary role of oxygen in cellular respiration is to

A)yield energy in the form of ATP as it is passed down the respiratory chain.
B)act as an acceptor for electrons and hydrogen, forming water.
C)combine with carbon, forming CO₂.
D)combine with lactate, forming pyruvate.
E)catalyze the reactions of glycolysis.

Question 45

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Approximately how many molecules of ATP are produced from the complete oxidation of two molecules of glucose (C₆H₁₂O₆)in cellular respiration?

A)2
B)4
C)15
D)38
E)76

Question 46

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Assume a mitochondrion contains 58 NADH and 19 FADH₂. If each of the 77 dinucleotides were used, approximately how many ATP molecules could be generated as a result of oxidative phosphorylation (chemiosmosis)?

A)36
B)77
C)173
D)212
E)1102

Question 47

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

During oxidative phosphorylation, H₂O is formed. Where does the oxygen for the synthesis of the water come from?

A)carbon dioxide (CO₂)
B)glucose (C₆H₁₂O₆)
C)molecular oxygen (O₂)
D)pyruvate (C₃H₃O₃⁻)
E)lactate (C₃H₅O₃⁻)

Question 48

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

For each molecule of glucose that is metabolized by glycolysis and the citric acid cycle, what is the total number of NADH + FADH₂ molecules produced?

A)4
B)5
C)6
D)10
E)12

Question 49

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

In chemiosmotic phosphorylation, what is the most direct source of energy that is used to convert ADP + Pi to ATP?

A)energy released as electrons flow through the electron transport system
B)energy released from substrate-level phosphorylation
C)energy released from ATP synthase pumping hydrogen ions from the mitochondrial matrix
D)energy released from movement of protons through ATP synthase
E)No external source of energy is required because the reaction is exergonic.

Question 50

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

It is possible to prepare vesicles from portions of the inner membrane of the mitochondrial components. Which one of the following processes could still be carried on by this isolated inner membrane?

A)the citric acid cycle
B)oxidative phosphorylation
C)glycolysis and fermentation
D)reduction of NAD⁺
E)both the citric acid cycle and oxidative phosphorylation

Question 51

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation is

A)oxidation of glucose to CO² and water.
B)the thermodynamically favorable flow of electrons from NADH to the mitochondrial electron transport carriers.
C)the final transfer of electrons to oxygen.
D)the difference in H⁺ concentrations on opposite sides of the inner mitochondrial membrane.
E)the thermodynamically favorable transfer of phosphate from glycolysis and the citric acid cycle intermediate molecules of ADP.

Question 52

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Inside an active mitochondrion, most electrons follow which pathway?

A)glycolysis → NADH → oxidative phosphorylation → ATP → oxygen
B)citric acid cycle → FADH2 → electron transport chain → ATP
C)electron transport chain → citric acid cycle → ATP → oxygen
D)pyruvate → citric acid cycle → ATP → NADH → oxygen
E)citric acid cycle → NADH → electron transport chain → oxygen

Question 53

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Cellular respiration harvests the most chemical energy from which of the following?

A)substrate-level phosphorylation
B)chemiosmotic phosphorylation
C)converting oxygen to ATP
D)transferring electrons from organic molecules to pyruvate
E)generating carbon dioxide and oxygen in the electron transport chain

Question 54

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

A young animal has never had much energy. He is brought to a veterinarian for help and is sent to the animal hospital for some tests. There they discover his mitochondria can use only fatty acids and amino acids for respiration, and his cells produce more lactate than normal. Of the following, which is the best explanation of his condition?

A)His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane.
B)His cells cannot move NADH from glycolysis into the mitochondria.
C)His cells contain something that inhibits oxygen use in his mitochondria.
D)His cells lack the enzyme in glycolysis that forms pyruvate.
E)His cells have a defective electron transport chain, so glucose goes to lactate instead of to acetyl CoA.

Question 55

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level?

A)NAD⁺
B)NADH
C)ATP
D)ADP + Pi
E)FADH₂

Question 56

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Each time a molecule of glucose (C₆H₁₂O₆)is completely oxidized via aerobic respiration, how many oxygen molecules (O₂)are required?

A)1
B)2
C)6
D)12
E)38

Question 57

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Which of the following describes the sequence of electron carriers in the electron transport chain, starting with the least electronegative?

A)ubiquinone (Q), cytochromes (Cyt), FMN, Fe•S
B)cytochromes (Cyt), FMN, ubiquinone, Fe•S
C)Fe•S, FMN, cytochromes (Cyt), ubiquinone
D)FMN, Fe•S, ubiquinone, cytochromes (Cyt)
E)cytochromes (Cyt), Fe•S, ubiquinone, FMN

Question 58

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the

A)formation of ATP.
B)reduction of NAD⁺.
C)restoration of the Na⁺/K⁺ balance across the membrane.
D)creation of a proton gradient.
E)lowering of pH in the mitochondrial matrix.

Question 59

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Where is ATP synthase located in the mitochondrion?

A)cytosol
B)electron transport chain
C)outer membrane
D)inner membrane
E)mitochondrial matrix

Question 60

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Where are the proteins of the electron transport chain located?

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

Question 61

Figure 9.3
Which of the following normally occurs whether or not oxygen (O₂)is present?

A)glycolysis
B)fermentation
C)oxidation of pyruvate to acetyl CoA
D)citric acid cycle
E)oxidative phosphorylation (chemiosmosis)

Question 62

Figure 9.3
Which of the following couples chemiosmosis to energy storage?

A)NADH
B)FADH₂
C)cytochromes
D)electron transport
E)ATP synthase

Question 63

Use the following to answer the following questions.
Exposing inner mitochondrial membranes to ultrasonic vibrations will disrupt the membranes. However, the fragments will reseal "inside out." These little vesicles that result can still transfer electrons from NADH to oxygen and synthesize ATP. If the membranes are agitated still further however, the ability to synthesize ATP is lost.
After the second agitation of the membrane vesicles, what must be lost from the membrane?

A)the ability of NADH to transfer electrons to the first acceptor in the electron transport chain
B)the prosthetic groups like heme from the transport system
C)cytochromes
D)ATP synthase, in whole or in part
E)the contact required between inner and outer membrane surfaces

Question 64

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Approximately what percentage of the energy of glucose (C₆H₁₂O₆)is transferred to storage in ATP as a result of the complete oxidation of glucose to CO₂ and water in cellular respiration?

A)2%
B)4%
C)10%
D)25%
E)40%

Question 65

Figure 9.3
In alcohol fermentation, NAD⁺ is regenerated from NADH during which of the following?

A)reduction of acetaldehyde to ethanol (ethyl alcohol)
B)oxidation of pyruvate to acetyl CoA
C)reduction of pyruvate to form lactate
D)oxidation of NAD⁺ in the citric acid cycle
E)phosphorylation of ADP to form ATP

Question 66

Figure 9.3
The parts of the figure labeled with Roman numerals symbolize what concept?

A)different inner mitochondrial membranes
B)different mitochondria functioning together
C)molecules with different attached metal ions
D)carbohydrate framework holding the molecules in place
E)multimeric groups of proteins in 4 complexes

Question 67

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

In liver cells, the inner mitochondrial membranes are about 5 X the area of the outer mitochondrial membranes, and about 17 X that of the cell's plasma membrane. What purpose must this serve?

A)It allows for increased rate of glycolysis.
B)It allows for increased rate of the citric acid cycle.
C)It increases the surface for oxidative phosphoryation.
D)It increases the surface for substrate-level phosphorylation.
E)It allows the liver cell to have fewer mitochondria.

Question 68

Figure 9.3
Which of the following occurs in the cytosol of a eukaryotic cell?

A)glycolysis and fermentation
B)fermentation and chemiosmosis
C)oxidation of pyruvate to acetyl CoA
D)citric acid cycle
E)oxidative phosphorylation

Question 69

Figure 9.3
Which metabolic pathway is common to both cellular respiration and fermentation?

A)the oxidation of pyruvate to acetyl CoA
B)the citric acid cycle
C)oxidative phosphorylation
D)glycolysis
E)chemiosmosis

Question 70

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Recall that the complete oxidation of a mole of glucose releases 686 kcal of energy (ΔG = -686 kcal/mol). The phosphorylation of ADP to form ATP stores approximately 7.3 kcal per mole of ATP. What is the approximate efficiency of cellular respiration for a "mutant" organism that produces only 29 moles of ATP for every mole of glucose oxidized, rather than the usual 36-38 moles of ATP?

A)0)4%
B)25%
C)30%
D)40%
E)60%

Question 71

Figure 9.3
The accompanying figure shows the electron transport chain. Which of the following is the combination of substances that is initially added to the chain?

A)oxygen, carbon dioxide, and water
B)NAD⁺ , FAD, and electrons
C)NADH, FADH₂, and protons
D)NADH, FADH₂, and electrons
E)Oxygen and electrons

Question 72

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

What is proton-motive force?

A)the force required to remove an electron from hydrogen
B)the transmembrane proton concentration gradient
C)movement of hydrogen into the intermembrane space
D)movement of hydrogen into the mitochondrion
E)the addition of hydrogen to NAD⁺

Question 73

Figure 9.3
Which of the following describes ubiquinone?

A)a protein in the electron transport chain
B)a small hydrophobic coenzyme
C)a substrate for synthesis of FADH
D)a vitamin needed for efficient glycolysis
E)an essential amino acid

Question 74

Use the following to answer the following questions.
Exposing inner mitochondrial membranes to ultrasonic vibrations will disrupt the membranes. However, the fragments will reseal "inside out." These little vesicles that result can still transfer electrons from NADH to oxygen and synthesize ATP. If the membranes are agitated still further however, the ability to synthesize ATP is lost.
It should be possible to reconstitute the abilities of the vesicles if which of the following is added?

A)cytochromes
B)extra NADH
C)a second membrane surface
D)more electrons
E)intact ATP synthase

Question 75

Figure 9.3
In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of

A)ATP, CO₂, and ethanol (ethyl alcohol).
B)ATP, CO₂, and lactate.
C)ATP, NADH, and pyruvate.
D)ATP, pyruvate, and oxygen.
E)ATP, pyruvate, and acetyl CoA.

Question 76

Figure 9.3
The ATP made during fermentation is generated by which of the following?

A)the electron transport chain
B)substrate-level phosphorylation
C)chemiosmosis
D)oxidative phosphorylation
E)aerobic respiration

Question 77

Use the following to answer the following questions.
Exposing inner mitochondrial membranes to ultrasonic vibrations will disrupt the membranes. However, the fragments will reseal "inside out." These little vesicles that result can still transfer electrons from NADH to oxygen and synthesize ATP. If the membranes are agitated still further however, the ability to synthesize ATP is lost.
After the first disruption, when electron transfer and ATP synthesize still occur, what must be present?

A)all of the electron transport proteins as well as ATP synthase
B)all of the electron transport system and the ability to add CoA to acetyl groups
C)the ATP synthase system is sufficient
D)the electron transport system is sufficient
E)plasma membranes like those bacteria use for respiration

Question 78

Figure 9.3
Which of the following most accurately describes what is happening along this chain?

A)Chemiosmosis is coupled with electron transfer.
B)Each electron carrier alternates between being reduced and being oxidized.
C)ATP is generated at each step.
D)Energy of the electrons increases at each step.
E)Molecules in the chain give up some of their potential energy.

Question 79

Figure 9.3
One function of both alcohol fermentation and lactic acid fermentation is to

A)reduce NAD⁺ to NADH.
B)reduce FAD⁺ to FADH₂.
C)oxidize NADH to NAD⁺.
D)reduce FADH₂ to FAD⁺.
E)none of the above

Question 80

Figure 9.3
What happens at the end of the chain?

A)The 2 original electrons combine with NAD⁺.
B)The 2 original electrons combine with oxygen.
C)4 electrons combine with oxygen and protons.
D)4 electrons combine with hydrogen and oxygen atoms.
E)1 electron combines with oxygen and hydrogen.