Question 1

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

Accepted Answer

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. 
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 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.
  
-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?

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 3

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?

Accepted Answer

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

Question 4

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

Accepted Answer

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. 
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 5

Figure 9.3  
-What is the reducing agent in the following reaction?
Pyruvate + NADH + H⁺ → Lactate + NAD⁺

Accepted Answer

A) oxygen 
B) NADH 
C) NAD⁺ 
D) lactate 
E) pyruvate 
A) oxygen 
B) NADH 
C) NAD⁺ 
D) lactate 
E) pyruvate

Question 6

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 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. 
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 7

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?

Accepted Answer

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 
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 8

Figure 9.3  
-What happens at the end of the chain?

Accepted Answer

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. 
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.

Question 9

Figure 9.3  
-In mitochondria, exergonic redox reactions

Accepted Answer

A) are the source of energy driving prokaryotic ATP synthesis. 
B) are directly coupled to substrate-level phosphorylation. 
C) provide the energy that establishes the proton gradient. 
D) reduce carbon atoms to carbon dioxide. 
E) are coupled via phosphorylated intermediates to endergonic processes. 
A) are the source of energy driving prokaryotic ATP synthesis. 
B) are directly coupled to substrate-level phosphorylation. 
C) provide the energy that establishes the proton gradient. 
D) reduce carbon atoms to carbon dioxide. 
E) are coupled via phosphorylated intermediates to endergonic processes.

Question 10

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 COS1U1B12S1U1B0, 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?

Accepted Answer

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

Question 11

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?

Accepted Answer

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 
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 12

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

Accepted Answer

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. 
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 13

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?

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 14

Figure 9.3  
-Muscle cells, when an individual is exercising heavily and when the muscle becomes oxygen deprived, convert pyruvate to lactate. What happens to the lactate in skeletal muscle cells?

Accepted Answer

A) It is converted to NAD⁺. 
B) It produces CO₂ and water. 
C) It is taken to the liver and converted back to pyruvate. 
D) It reduces FADH₂ to FAD⁺. 
E) It is converted to alcohol. 
A) It is converted to NAD⁺. 
B) It produces CO₂ and water. 
C) It is taken to the liver and converted back to pyruvate. 
D) It reduces FADH₂ to FAD⁺. 
E) It is converted to alcohol.

Question 15

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

Accepted Answer

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. 
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 16

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

Accepted Answer

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

Question 17

Figure 9.3  
-Why is glycolysis considered to be one of the first metabolic pathways to have evolved?

Accepted Answer

A) It produces much less ATP than does oxidative phosphorylation. 
B) It is found in the cytosol, does not involve 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 the first cells-prokaryotic cells. 
E) It requires the presence of membrane-enclosed cell organelles found only in eukaryotic cells. 
A) It produces much less ATP than does oxidative phosphorylation. 
B) It is found in the cytosol, does not involve 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 the first cells-prokaryotic cells. 
E) It requires the presence of membrane-enclosed cell organelles found only in eukaryotic cells.

Question 18

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?

Accepted Answer

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

Question 19

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?

Accepted Answer

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 
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 20

Figure 9.3  
-When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?

Accepted Answer

A) The pH of the matrix increases. 
B) ATP synthase pumps protons by active transport. 
C) The electrons gain free energy. 
D) The cytochromes phosphorylate ADP to form ATP. 
E) NAD⁺ is oxidized. 
A) The pH of the matrix increases. 
B) ATP synthase pumps protons by active transport. 
C) The electrons gain free energy. 
D) The cytochromes phosphorylate ADP to form ATP. 
E) NAD⁺ is oxidized.

Exam 9: Cellular Respiration: Harvesting Chemical Energy

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

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

Figure 9.3 -What is the reducing agent in the following reaction? Pyruvate + NADH + H⁺ → Lactate + NAD⁺

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

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?

Figure 9.3 -What happens at the end of the chain?

Figure 9.3 -In mitochondria, exergonic redox reactions

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?

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

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?

Figure 9.3 -Muscle cells, when an individual is exercising heavily and when the muscle becomes oxygen deprived, convert pyruvate to lactate. What happens to the lactate in skeletal muscle cells?

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

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

Figure 9.3 -Why is glycolysis considered to be one of the first metabolic pathways to have evolved?

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?

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?

Figure 9.3 -When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and the Fitness of the Environment

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

Control 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 Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure, Growth, and Development

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

Conservation Biology and Restoration Ecology

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