Question 1

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

Accepted Answer

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. 
E)  The more electronegative atom is reduced, and entropy decreases. 
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. 
E)  The more electronegative atom is reduced, and entropy decreases.

Question 2

Figure 9.3
-Which of the protein complexes labeled with Roman numerals in Figure 9.3 will transfer electrons to O₂?

Accepted Answer

A)  complex I 
B)  complex II 
C)  complex III 
D)  complex IV 
E)  All of the complexes can transfer electrons to O₂. 
A)  complex I 
B)  complex II 
C)  complex III 
D)  complex IV 
E)  All of the complexes can transfer electrons to O₂.

Question 3

Where is ATP synthase located in the mitochondrion?

Accepted Answer

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

Question 4

Phosphofructokinase is an important control enzyme in the regulation of cellular respiration. Which of the following statements correctly describes phosphofructokinase activity?

Accepted Answer

A)  It is inhibited by AMP. 
B)  It is activated by ATP. 
C)  It is activated by citrate, an intermediate of the citric acid cycle. 
D)  It catalyzes the conversion of fructose 1,6-bisphosphate to fructose 6-phosphate, an early step of glycolysis. 
E)  It is an allosteric enzyme. 
A)  It is inhibited by AMP. 
B)  It is activated by ATP. 
C)  It is activated by citrate, an intermediate of the citric acid cycle. 
D)  It catalyzes the conversion of fructose 1,6-bisphosphate to fructose 6-phosphate, an early step of glycolysis. 
E)  It is an allosteric enzyme.

Question 5

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.
   
Figure 9.1
-Which portion of the pathway in Figure 9.1 contains a phosphorylation reaction in which ATP is the phosphate source?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
E)  E 
A)  A 
B)  B 
C)  C 
D)  D 
E)  E

Question 6

Figure 9.2 The citric acid cycle.
-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 (see Figure 9.2)?

Accepted Answer

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

Question 7

Even though plants carry on photosynthesis, plant cells still use their mitochondria for oxidation of pyruvate. When and where will this occur?

Accepted Answer

A)  in photosynthetic cells in the light, while photosynthesis occurs concurrently 
B)  in nonphotosynthesizing cells only 
C)  in cells that are storing glucose only 
D)  in all cells all the time 
E)  in photosynthesizing cells in the light and in other tissues in the dark 
A)  in photosynthetic cells in the light, while photosynthesis occurs concurrently 
B)  in nonphotosynthesizing cells only 
C)  in cells that are storing glucose only 
D)  in all cells all the time 
E)  in photosynthesizing cells in the light and in other tissues in the dark

Question 8

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

Accepted Answer

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

Question 9

Starting with one molecule of glucose, the energy-containing products of glycolysis are

Accepted Answer

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 ATP, and 2 pyruvate. 
E)  6 CO₂, 30 ATP, and 2 pyruvate. 
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 ATP, and 2 pyruvate. 
E)  6 CO₂, 30 ATP, and 2 pyruvate.

Question 10

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

Accepted Answer

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

Question 11

The free energy for the oxidation of glucose to CO₂ and water is -686 kcal/mol and the free energy 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?

Accepted Answer

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. 
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 12

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?

Accepted Answer

A)  Glycolysis is widespread and is found in the domains Bacteria, Archaea, and Eukarya. 
B)  Glycolysis neither uses nor needs O₂. 
C)  Glycolysis is found in all eukaryotic cells. 
D)  The enzymes of glycolysis are found in the cytosol rather than in a membrane-enclosed organelle. 
E)  Ancient prokaryotic cells, the most primitive of cells, made extensive use of glycolysis long before oxygen was present in Earth's atmosphere. 
A)  Glycolysis is widespread and is found in the domains Bacteria, Archaea, and Eukarya. 
B)  Glycolysis neither uses nor needs O₂. 
C)  Glycolysis is found in all eukaryotic cells. 
D)  The enzymes of glycolysis are found in the cytosol rather than in a membrane-enclosed organelle. 
E)  Ancient prokaryotic cells, the most primitive of cells, made extensive use of glycolysis long before oxygen was present in Earth's atmosphere.

Question 13

The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the

Accepted Answer

A)  oxidation of glucose and other organic compounds. 
B)  flow of electrons down the electron transport chain. 
C)  affinity of oxygen for electrons. 
D)  H⁺ concentration across the membrane holding ATP synthase. 
E)  transfer of phosphate to ADP. 
A)  oxidation of glucose and other organic compounds. 
B)  flow of electrons down the electron transport chain. 
C)  affinity of oxygen for electrons. 
D)  H⁺ concentration across the membrane holding ATP synthase. 
E)  transfer of phosphate to ADP.

Question 14

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

Accepted Answer

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

Question 15

What is proton-motive force?

Accepted Answer

A)  the force required to remove an electron from hydrogen 
B)  the force exerted on a proton by a transmembrane proton concentration gradient 
C)  the force that moves hydrogen into the intermembrane space 
D)  the force that moves hydrogen into the mitochondrion 
E)  the force that moves hydrogen to NAD⁺ 
A)  the force required to remove an electron from hydrogen 
B)  the force exerted on a proton by a transmembrane proton concentration gradient 
C)  the force that moves hydrogen into the intermembrane space 
D)  the force that moves hydrogen into the mitochondrion 
E)  the force that moves hydrogen to NAD⁺

Question 16

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

Accepted Answer

A)  The covalent bonds in organic molecules and molecular oxygen have more kinetic energy than the covalent bonds 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. 
A)  The covalent bonds in organic molecules and molecular oxygen have more kinetic energy than the covalent bonds 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 17

During glycolysis, when each molecule of glucose is catabolized to two molecules of pyruvate, most of the potential energy contained in glucose is

Accepted Answer

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

Question 18

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?

Accepted Answer

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 be readily transferred to a compound in the citric acid cycle 
D)  because it drives the reaction that regenerates NAD⁺ 
E)  in order to remove one molecule of CO₂ 
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 be readily transferred to a compound in the citric acid cycle 
D)  because it drives the reaction that regenerates NAD⁺ 
E)  in order to remove one molecule of CO₂

Question 19

A molecule that is phosphorylated

Accepted Answer

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 potential energy; it is primed to do cellular work. 
E)  has less energy than before its phosphorylation and therefore less energy for cellular work. 
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 potential energy; it is primed to do cellular work. 
E)  has less energy than before its phosphorylation and therefore less energy for cellular work.

Question 20

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.
   
Figure 9.1
-Which portion of the pathway in Figure 9.1 involves an endergonic reaction?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
E)  E 
A)  A 
B)  B 
C)  C 
D)  D 
E)  E

Exam 9: Cellular Respiration and Fermentation

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

Figure 9.3 -Which of the protein complexes labeled with Roman numerals in Figure 9.3 will transfer electrons to O₂?

Where is ATP synthase located in the mitochondrion?

Phosphofructokinase is an important control enzyme in the regulation of cellular respiration. Which of the following statements correctly describes phosphofructokinase activity?

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. Figure 9.1 -Which portion of the pathway in Figure 9.1 contains a phosphorylation reaction in which ATP is the phosphate source?

Figure 9.2 The citric acid cycle. -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 (see Figure 9.2)?

Even though plants carry on photosynthesis, plant cells still use their mitochondria for oxidation of pyruvate. When and where will this occur?

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

Starting with one molecule of glucose, the energy-containing products of glycolysis are

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

The free energy for the oxidation of glucose to CO₂ and water is -686 kcal/mol and the free energy 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?

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?

The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the

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

What is proton-motive force?

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

During glycolysis, when each molecule of glucose is catabolized to two molecules of pyruvate, most of the potential energy contained in glucose is

A molecule that is phosphorylated

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. Figure 9.1 -Which portion of the pathway in Figure 9.1 involves an endergonic reaction?

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Regulation of Gene Expression

Viruses

Biotechnology

Genomes and Their Evolution

Descent with Modification: A Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity II: The Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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