Deck 7: Cellular Respiration and Fermentation

Question 1

Which of the following terms describes metabolic pathways that break down complex molecules to release stored energy?

A)catabolic pathways
B)anabolic pathways
C)bioenergetic pathways
D)endergonic pathways

Answer 1

A

Question 2

Which of the following indicates a primary path by which electrons travel downhill energetically during aerobic respiration?

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

Answer 2

B

Question 3

Which of the following metabolic processes 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

Answer 3

B

Question 4

As a result of an oxidation-reduction reaction,how is the oxidizing agent changed?

A)It gains electrons and gains potential energy.
B)It gains electrons and loses potential energy.
C)It loses electrons and loses potential energy.
D)It loses electrons and gains potential energy.

Question 5

Approximately what percentage of the ATP formed by the reactions of glycolysis is produced by substrate-level phosphorylation?

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

Question 6

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

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

Question 7

The complete reactions of cellular respiration in the presence of oxygen (C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + energy)result in which of the following?

A)oxidation of O₂ and reduction of H₂O
B)oxidation of C₆H₁₂O₆ and reduction of O₂
C)reduction of CO₂ and oxidation of O₂
D)reduction of C₆H₁₂O₆ and oxidation of CO₂

Question 8

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 9

Why are carbohydrates and fats considered high-energy foods?

A)They have many oxygen atoms.
B)They have few nitrogen atoms.
C)They have a large number of electrons associated with hydrogen.
D)They have many carbon atoms bound together by single covalent bonds.

Question 10

How many molecules of oxygen (O₂)are consumed by the complete oxidation of glucose (C₆H₁₂O₆)to carbon dioxide and water in aerobic respiration?

A)1
B)3
C)6
D)12
E)36

Question 11

Where does glycolysis occur in animal cells?

A)cytosol
B)outer mitochondrial membrane
C)inner mitochondrial membrane
D)mitochondrial matrix

Question 12

Which of the following statements about NAD⁺ is true?

A)NAD⁺ is the source of electrons used in oxidative phosphorylation.
B)NAD⁺ has more chemical energy than NADH.
C)NAD⁺ is oxidized by the action of dehydrogenase enzymes.
D)NAD⁺ is reduced to NADH during glycolysis.

Question 13

Which chemical process generates the ATP produced in glycolysis?

A)chemiosmosis
B)electron transport
C)photophosphorylation
D)oxidative phosphorylation
E)substrate-level phosphorylation

Question 14

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

A)dehydrogenated.
B)oxidized.
C)reduced.
D)redoxed.
E)hydrolyzed.

Question 15

Which of the following situations results from the transfer of an electron to a more electronegative atom?

A)The electron loses potential energy.
B)The electron gains potential energy.
C)The electron gains kinetic energy.
D)The electron oxidizes the more electronegative atom.

Question 16

Approximately what percentage of the ATP formed by the electron transport chain is produced by substrate-level phosphorylation?

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

Question 17

Which of the following describes the result of transferring an electron from a less electronegative atom to a more electronegative atom?

A)The more electronegative atom is reduced,and energy is released.
B)The more electronegative atom is reduced,and energy is consumed.
C)The more electronegative atom is oxidized,and energy is consumed.
D)The more electronegative atom is oxidized,and energy is released.

Question 18

In an oxidation-reduction reaction,how is the reducing agent changed?

A)It gains electrons and gains potential energy.
B)It gains electrons and loses potential energy.
C)It loses electrons and loses potential energy.
D)It loses electrons and gains potential energy.

Question 19

Which of the following sequences represents the correct order in which metabolic reactions occur during the complete oxidation of glucose through aerobic respiration?

A)glucose → citric acid cycle → glycolysis → pyruvate oxidation → electron transport chain
B)glucose → pyruvate oxidation → glycolysis → electron transport chain → citric acid cycle
C)glucose → glycolysis → pyruvate oxidation → citric acid cycle → electron transport chain
D)glucose → glycolysis → citric acid cycle → pyruvate oxidation → electron transport chain
E)glucose → pyruvate oxidation → citric acid cycle → glycolysis → electron transport chain

Question 20

Which chemical process generates the ATP produced in the citric acid cycle?

A)chemiosmosis
B)electron transport
C)photophosphorylation
D)oxidative phosphorylation
E)substrate-level phosphorylation

Question 21

In the complete reactions of aerobic respiration,the energy for most of the ATP produced is provided by

A)transfer of electrons from organic molecules to acetyl CoA.
B)high-energy phosphate bonds from organic molecule intermediates in the citric acid cycle.
C)splitting water to produce oxygen.
D)a proton gradient across a membrane.

Question 22

The free-energy change for the oxidation of glucose to CO₂ and water is -686 kcal/mol,and the free-energy change for the reduction of NAD⁺ to NADH is +53 kcal/mol.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 captured by the production of ATP.
B)Glycolysis is a very inefficient process,with much of the energy from 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)Glycolysis consists of many enzyme-catalyzed reactions,each of which extracts a small amount of energy from the glucose molecule.

Question 23

Catabolism of each molecule of glucose in glycolysis is associated with a net consumption of which of the following other molecules?

A)2 NAD⁺,2 pyruvate,and 2 ATP
B)4 NAD⁺,2 pyruvate,and 4 ADP
C)2 NAD⁺ and 4 ADP
D)2 NAD⁺ and 2 ADP
E)2 NADH and 2 ADP

Question 24

Assuming glucose is the only energy source for a cell,what fraction of the carbon dioxide produced by aerobic respiration is generated by the reactions of the citric acid cycle?

A)1/6
B)1/3
C)1/2
D)2/3
E)all of it

Question 25

Upon completion of glycolysis,what is the fate of the majority of the potential energy contained in the original glucose molecule?

A)It is stored in two ATP molecules.
B)It is released as heat.
C)It is retained in two pyruvate molecules.
D)It is stored in the two NADH molecules.

Question 26

Which of the following statements correctly describes how ATP is involved in the oxidation of one molecule of glucose in glycolysis?

A)Two molecules of ATP are used,and two molecules of ATP are produced.
B)Two molecules of ATP are used,and four molecules of ATP are produced.
C)Four molecules of ATP are used,and two molecules of ATP are produced.
D)Two molecules of ATP are used,and six molecules of ATP are produced.

Question 27

Which of the following molecules donates electrons directly to the electron transport chain at the lowest energy level?

A)NAD⁺
B)NADH
C)ATP
D)FAD
E)FADH₂

Question 28

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)glycolysis and the citric acid cycle

Question 29

In addition to ATP,what are the 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 30

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 31

Which of the following molecules donates electrons directly to the electron transport chain at the highest energy level?

A)NAD⁺
B)NADH
C)ATP
D)FAD
E)FADH₂

Question 32

What is the primary role of oxygen in cellular respiration?

A)to donate high energy electrons to the electron transport chain
B)to serve as an acceptor for released carbon,forming CO₂
C)to serve as an acceptor for electrons and protons,forming water
D)to donate high energy electrons to NAD⁺,forming NADH

Question 33

Where are the proteins of the electron transport chain located in a eukaryotic cell?

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

Question 34

For each molecule of glucose that is catabolized in glycolysis and the citric acid cycle,how many NADH molecules are produced?

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

Question 35

Glycolysis results in a net production of which of the following molecules from each molecule of glucose?

A)2 NAD⁺,2 pyruvate,and 2 ATP
B)4 NADH,2 pyruvate,and 4 ATP
C)2 NADH,2 pyruvate,and 2 ATP
D)6 CO₂,2 NADH,2 pyruvate,and 2 ATP
E)6 CO₂,2 pyruvate,and 30 ATP

Question 36

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

A)Early steps consume energy from ATP and NADH,and later steps store an equal amount of energy in ATP and NAD⁺.
B)Early steps consume energy from ATP and NADH,and later steps store an increased amount of energy in ATP and NADH.
C)Early steps consume energy from ATP and NADH,and later steps store an increased amount of energy in ATP.
D)Early steps consume energy from ATP,and later steps store an increased amount of energy in ATP and NADH.
E)Early steps consume energy from NADH,and later steps store an increased amount of energy in ATP and NADH.

Question 37

Which of the following correctly lists all of the energy-containing molecules produced by the catabolism of one molecule of glucose in glycolysis?

A)2 NAD⁺,2 pyruvate,and 2 ATP
B)2 NADH,2 pyruvate,and 2 ATP
C)2 FADH₂,2 pyruvate,and 4 ATP
D)6 CO₂,2 pyruvate,and 2 ATP
E)6 CO₂,2 pyruvate,and 30 ATP

Question 38

How many carbon atoms from one molecule of pyruvate enter the citric acid cycle?

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

Question 39

Which of the following statements is true for a molecule that is phosphorylated?

A)It has been reduced as a result of a redox reaction involving the loss of an inorganic phosphate.
B)It has a decreased chemical energy and is less likely to provide energy for cellular work.
C)It has been oxidized as a result of a redox reaction involving the gain of an inorganic phosphate.
D)It has increased chemical potential energy that may be used to do cellular work.

Question 40

Assuming glucose is the only energy source for a cell,what fraction of the carbon dioxide produced by aerobic respiration is generated by the oxidation of pyruvate to acetyl CoA?

A)1/6
B)1/3
C)1/2
D)2/3
E)all of it

Question 41

What is the immediate source of the energy used to synthesize ATP by oxidative phosphorylation in eukaryotic cells?

A)oxidation of glucose to CO₂ and water
B)the thermodynamically favorable flow of electrons from NADH to proteins associated with the mitochondrial electron transport chain
C)the transfer of protons and electrons to oxygen
D)the proton-motive force across the inner mitochondrial membrane
E)the thermodynamically favorable transfer of high-energy phosphate groups from molecules in glycolysis and the citric acid cycle to ADP

Question 42

In liver cells,the inner mitochondrial membranes are about five times the area of the outer mitochondrial membranes.What purpose must this serve?

A)It increases the surface area for glycolysis.
B)It increases the surface area for the citric acid cycle.
C)It increases the surface area for oxidative phosphorylation.
D)It increases the surface area for substrate-level phosphorylation.

Question 43

The complete oxidation of two molecules of glucose (C₆H₁₂O₆)in cellular respiration produces about how many molecules of ATP?

A)2
B)4
C)15
D)30-32
E)60-64

Question 44

Which organelles or organisms are capable of synthesizing ATP using energy from chemiosmosis?

A)only mitochondria in animal cells
B)only bacteria that generate proton gradients across their plasma membranes
C)only mitochondria and chloroplasts
D)only mitochondria and bacteria that generate proton gradients across their plasma membranes
E)mitochondria,chloroplasts,and bacteria that generate proton gradients across their plasma membranes

Question 45

What is the proton-motive force?

A)the energy required to remove an electron from a hydrogen atom
B)the energy provided by a transmembrane hydrogen ion gradient
C)the energy that moves hydrogen into the intermembrane space
D)the energy that moves hydrogen atoms into the mitochondrion

Question 46

The oxygen atoms used to form water in the complete reactions of cellular respiration are derived from which of the following molecules?

A)carbon dioxide (CO₂)
B)glucose (C₆H₁₂O₆)
C)pyruvate (C₃H₃O₃^-)
D)molecular oxygen (O₂)

Question 47

Under anaerobic conditions,what carbon sources can be metabolized by yeast cells to produce ATP from ADP?

A)glucose
B)ethanol
C)pyruvate
D)lactic acid

Question 48

If 30 molecules of ATP are produced for each molecule of glucose completely oxidized to carbon dioxide and water,how many ATP molecules will be produced for each molecule of pyruvate completely oxidized to carbon dioxide and water?

A)2
B)6
C)14
D)28
E)60

Question 49

Which of the following metabolic processes 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 50

In chemiosmosis,what is the most direct source of energy that is used to convert ADP + ℗_i 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 hydrolysis
D)energy released from movement of protons down their electrochemical gradient through ATP synthase

Question 51

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

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

Question 52

In vertebrate animals,brown fat tissue's color is derived from abundant blood vessels and capillaries.White fat tissue,on the other hand,is specialized for fat storage and contains relatively few blood vessels or capillaries.Brown fat cells produce the protein thermogenin,which is an ion channel that facilitates diffusion of protons across the membrane.Which of the following statements might best describe the function of the brown fat tissue?

A)to increase the rate of oxidative phosphorylation from its few mitochondria
B)to increase the metabolic rate when it is especially hot
C)to increase the rate of ATP production
D)to regulate temperature by converting most of the energy from the mitochondrial proton gradient to heat

Question 53

What is the source of the energy used to generate the proton gradient across the inner mitochondrial membrane?

A)ATP hydrolysis
B)redox reactions in the electron transport chain
C)decreasing the pH in the mitochondrial matrix
D)splitting water to form oxygen and protons

Question 54

Inside an active mitochondrion,most electrons follow which of the following pathways?

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

Question 55

In the complete oxidation of a molecule of glucose (C₆H₁₂O₆)in aerobic cellular respiration,how many molecules of ATP are produced by substrate-level phosphorylation?

A)2
B)4
C)8
D)30-32

Question 56

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

A)the formation of ATP.
B)the reduction of NAD⁺.
C)a decrease in the pH of the mitochondrial matrix.
D)the creation of a proton-motive force.

Question 57

The synthesis of ATP by oxidative phosphorylation,using the energy released by movement of protons across the membrane down their electrochemical gradient,is an example of

A)conversion of potential energy to kinetic energy.
B)an endergonic reaction coupled to an exergonic reaction.
C)a redox reaction.
D)allosteric regulation.

Question 58

Where in mitochondria is the enzyme ATP synthase localized?

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

Question 59

In a mitochondrion,if the matrix ATP concentration is high and there is no proton gradient across the inner mitochondrial membrane to generate a proton-motive force,then what might you expect to occur?

A)ATP synthase will increase the rate of ATP synthesis.
B)ATP synthase will synthesize ATP and pump protons into the intermembrane space.
C)ATP synthase will hydrolyze ATP and pump protons into the intermembrane space.
D)ATP synthase will hydrolyze ATP and pump protons into the matrix.

Question 60

Brown fat cells produce a protein called thermogenin in their mitochondrial inner membrane.Thermogenin is an ion channel that facilitates diffusion of protons across the membrane.What will occur in the brown fat cells when thermogenin is present in their inner mitochondrial membranes?

A)ATP synthesis and heat generation will both increase.
B)ATP synthesis will increase,and heat generation will decrease.
C)ATP synthesis will decrease,and heat generation will increase.
D)ATP synthesis and heat generation will both decrease.

Question 61

Which of the following metabolic pathways requires a proton gradient?

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

Question 62

During strenuous exercise,human muscle cells can become oxygen-deprived.When this occurs,muscle cells perform anaerobic fermentation,which results in the production of lactate from pyruvate.What happens to the lactate produced in muscle cells?

A)It is reduced and converted back to pyruvate in muscle cells.
B)It is oxidized to CO₂ and water.
C)It is taken to the liver and converted back to pyruvate.
D)It is converted to alcohol.

Question 63

Yeast cells grown anaerobically can obtain energy by fermentation,which results in the production of

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

Question 64

Which catabolic processes may have been used by cells on ancient Earth before free oxygen became available?

A)only glycolysis and fermentation
B)only glycolysis and the citric acid cycle
C)only glycolysis and pyruvate oxidation
D)only oxidative phosphorylation,using an electron acceptor other than oxygen
E)glycolysis,pyruvate oxidation,the citric acid cycle,and oxidative phosphorylation,using an electron acceptor other than oxygen

Question 65

Which of the following metabolic pathways is common to both aerobic cellular respiration and anaerobic fermentation?

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

Question 66

Which statement best supports the hypothesis that glycolysis is an ancient metabolic pathway that originated before the last universal common ancestor of life on Earth?

A)Glycolysis is widespread and is found in the domains Bacteria,Archaea,and Eukarya.
B)Glycolysis neither uses nor requires O₂.
C)Glycolysis occurs in all eukaryotic cells.
D)The enzymes of glycolysis are localized in the cytosol rather than in a membrane-enclosed organelle.

Question 67

Which of the following processes is responsible for the ATP made during fermentation?

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

Question 68

Which of the following metabolic pathways occur(s)in mitochondria?

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

Question 69

Yeast cells with defective mitochondria are incapable of cellular respiration.Catabolism of which of the following energy sources would allow these to grow?

A)glucose
B)proteins
C)fatty acids
D)pyruvate

Question 70

Which one of the following molecules is formed by the removal of a carbon (as CO₂)from a molecule of pyruvate during aerobic respiration?

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

Question 71

In what form do the catabolic products of beta oxidation enter into the citric acid cycle?

A)as pyruvate
B)as glyceraldehyde 3-phosphate
C)as CO₂
D)as acetyl CoA
E)as glycerol

Question 72

Why is glycolysis considered to be one of the first metabolic pathways to have evolved?

A)It produces much less ATP than does oxidative phosphorylation.
B)It does not involve organelles or specialized structures,does not require oxygen,and is present in most organisms.
C)It is found in prokaryotic cells but not in eukaryotic cells.
D)It relies on chemiosmosis,which is a metabolic mechanism present only in prokaryotic cells.

Question 73

Figure 7.1
In the citric acid cycle (see Figure 7.1),beginning with one molecule of isocitrate and ending with fumarate,how many ATP molecules can be made through substrate-level phosphorylation?

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

Question 74

Which of the following metabolic pathways occur(s)in the cytosol of eukaryotic cells?

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

Question 75

Which of the following metabolic pathways generates a proton gradient?

A)the oxidation of pyruvate to acetyl CoA
B)the citric acid cycle
C)chemiosmosis
D)the electron transport chain
E)glycolysis

Question 76

What is the primary function of beta oxidation in respiration?

A)breakdown of glucose
B)breakdown of pyruvate
C)breakdown of proteins
D)breakdown of fatty acids

Question 77

During alcohol fermentation in yeast,NAD⁺ is regenerated from NADH by which of the following processes?

A)oxidation of ethanol to acetaldehyde
B)oxidation of pyruvate to acetyl CoA
C)reduction of pyruvate to lactate
D)reduction of acetaldehyde to ethanol
E)reduction of acetyl CoA to ethanol

Question 78

During intense exercise,as human muscle cells switch from respiration to fermentation,the cells will increase their catabolism of which of the following energy-containing molecules?

A)fats only
B)carbohydrates only
C)proteins only
D)fats,carbohydrates,and proteins
E)fats and proteins only

Question 79

Which of the following statements describes a primary function of both alcohol fermentation and lactic acid fermentation?

A)to reduce NAD⁺ to NADH
B)to reduce FAD⁺ to FADH₂
C)to oxidize NADH to NAD⁺
D)to oxidize FADH₂ to FAD

Question 80

A mutation in yeast knocks out the ability of cells to convert pyruvate to ethanol.How might this mutation affect these yeast cells?

A)The mutant yeast will be unable to metabolize glucose.
B)The mutant yeast will be unable to grow anaerobically.
C)The mutant yeast will be unable to grow aerobically.
D)The mutant yeast will grow anaerobically only when provided glucose.