Question 1

Which of the following statements is true for a system at chemical equilibrium?

Accepted Answer

A)  The system consumes energy at a steady rate. 
B)  The system releases energy at a steady rate. 
C)  The kinetic energy of the system is zero. 
D)  The system can do no work. 
A)  The system consumes energy at a steady rate. 
B)  The system releases energy at a steady rate. 
C)  The kinetic energy of the system is zero. 
D)  The system can do no work. D

Question 2

HIV is the virus that causes AIDS. In the mid-1990s, researchers discovered an enzyme in HIV called protease. Once the enzyme's structure was known, researchers began looking for drugs that would fit into the active site and block it. If this strategy for stopping HIV infections were successful, it would be an example of what phenomenon?

Accepted Answer

A)  noncompetitive inhibition 
B)  denaturation 
C)  allosteric regulation 
D)  competitive inhibition 
A)  noncompetitive inhibition 
B)  denaturation 
C)  allosteric regulation 
D)  competitive inhibition D

Question 3

Use the following information to answer the question below.
 
The figure illustrates the energy states associated with the reaction A + B ↔ C + D. Which of the following terms best describes the forward reaction in the figure?

Accepted Answer

A)  endergonic, ∆G > 0 
B)  exergonic, ∆G  0 
A)  endergonic, ∆G > 0 
B)  exergonic, ∆G  0 B

Question 4

Which of the following conditions may be overcome by increasing the substrate concentration in an enzymatic reaction with a fixed amount of enzyme?

Accepted Answer

A)  the need for a coenzyme 
B)  allosteric inhibition 
C)  noncompetitive inhibition 
D)  competitive inhibition 
A)  the need for a coenzyme 
B)  allosteric inhibition 
C)  noncompetitive inhibition 
D)  competitive inhibition

Question 5

During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a ∆G of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the ∆G for the new reaction?

Accepted Answer

A)  -40 kcal/mol 
B)  -20 kcal/mol 
C)  -10 kcal/mol 
D)  +20 kcal/mol 
A)  -40 kcal/mol 
B)  -20 kcal/mol 
C)  -10 kcal/mol 
D)  +20 kcal/mol

Question 6

Which of the following statements is an important consequence of the first law of thermodynamics for a living organism?

Accepted Answer

A)  The energy content of an organism is constant. 
B)  An organism ultimately must obtain all of the necessary energy for life from its environment. 
C)  The entropy of an organism decreases with time as the organism grows in complexity. 
D)  Organisms grow by converting energy into organic matter. 
A)  The energy content of an organism is constant. 
B)  An organism ultimately must obtain all of the necessary energy for life from its environment. 
C)  The entropy of an organism decreases with time as the organism grows in complexity. 
D)  Organisms grow by converting energy into organic matter.

Question 7

Chemical equilibrium is relatively rare in living cells because metabolic pathways are interconnected. Which of the following statements describes an example of a reaction that may be at chemical equilibrium in a cell?

Accepted Answer

A)  an exergonic reaction in which the free energy at equilibrium is higher than the energy content of the reaction at any point away from equilibrium 
B)  an exergonic reaction in which the entropy change in the cell is precisely balanced by an opposite entropy change in the cell's surroundings 
C)  a chemical reaction in which neither the reactants nor the products are being produced or consumed in any metabolic pathway at that time in the cell 
D)  an endergonic reaction in an active metabolic pathway where the energy for that reaction is supplied only by heat from the environment 
A)  an exergonic reaction in which the free energy at equilibrium is higher than the energy content of the reaction at any point away from equilibrium 
B)  an exergonic reaction in which the entropy change in the cell is precisely balanced by an opposite entropy change in the cell's surroundings 
C)  a chemical reaction in which neither the reactants nor the products are being produced or consumed in any metabolic pathway at that time in the cell 
D)  an endergonic reaction in an active metabolic pathway where the energy for that reaction is supplied only by heat from the environment

Question 8

A chemical reaction that has a positive ΔG is best described as ________.

Accepted Answer

A)  endergonic 
B)  enthalpic 
C)  spontaneous 
D)  exergonic 
A)  endergonic 
B)  enthalpic 
C)  spontaneous 
D)  exergonic

Question 9

Which of the following metabolic processes can occur without a net influx of energy from some other process?

Accepted Answer

A)  ADP +   → ATP + H₂O 
B)  C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O 
C)  6CO₂ + 6H₂0 → C₆H₁₂O₆ + 6O₂ 
D)  Amino acids → Protein 
A)  ADP +   → ATP + H₂O 
B)  C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O 
C)  6CO₂ + 6H₂0 → C₆H₁₂O₆ + 6O₂ 
D)  Amino acids → Protein

Question 10

Which of the following is an example of potential rather than kinetic energy?

Accepted Answer

A)  water rushing over Niagara Falls 
B)  light flashes emitted by a firefly 
C)  a molecule of glucose 
D)  a crawling beetle foraging for food 
A)  water rushing over Niagara Falls 
B)  light flashes emitted by a firefly 
C)  a molecule of glucose 
D)  a crawling beetle foraging for food

Question 11

Most cells cannot harness heat to perform work because

Accepted Answer

A)  heat does not involve a transfer of energy. 
B)  cells do not have much thermal energy; they are relatively cool. 
C)  temperature is usually uniform throughout a cell. 
D)  heat can never be used to do work. 
A)  heat does not involve a transfer of energy. 
B)  cells do not have much thermal energy; they are relatively cool. 
C)  temperature is usually uniform throughout a cell. 
D)  heat can never be used to do work.

Question 12

Which of the following characteristics is most likely to be associated with an enzyme that catalyzes two different chemical reactions?

Accepted Answer

A)  The enzyme contains α-helices and β-pleated sheets. 
B)  The enzyme is subject to competitive inhibition and allosteric regulation. 
C)  The enzyme is composed of at least two subunits. 
D)  Either the enzyme has two distinct active sites or the substrates involved in the two reactions have very similar structures. 
A)  The enzyme contains α-helices and β-pleated sheets. 
B)  The enzyme is subject to competitive inhibition and allosteric regulation. 
C)  The enzyme is composed of at least two subunits. 
D)  Either the enzyme has two distinct active sites or the substrates involved in the two reactions have very similar structures.

Question 13

Use the following information to answer the question below.
 
Rate of an enzyme-catalyzed reaction as a function of varying reactant concentration, with the concentration of enzyme constant
In the figure, why does the reaction rate plateau at higher reactant concentrations?

Accepted Answer

A)  Feedback inhibition by product occurs at high reactant concentrations. 
B)  Most enzyme molecules are occupied by substrate at high reactant concentrations. 
C)  The reaction nears equilibrium at high reactant concentrations. 
D)  The rate of the reverse reaction increases at high reactant concentrations. 
A)  Feedback inhibition by product occurs at high reactant concentrations. 
B)  Most enzyme molecules are occupied by substrate at high reactant concentrations. 
C)  The reaction nears equilibrium at high reactant concentrations. 
D)  The rate of the reverse reaction increases at high reactant concentrations.

Question 14

When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?

Accepted Answer

A)  It is used to power yet more cellular work. 
B)  It is captured to store energy as more ATP. 
C)  It is used to generate ADP from nucleotide precursors. 
D)  It is lost to the environment. 
A)  It is used to power yet more cellular work. 
B)  It is captured to store energy as more ATP. 
C)  It is used to generate ADP from nucleotide precursors. 
D)  It is lost to the environment.

Question 15

Which of the following statements about the evolution of life on Earth, from simple prokaryote-like cells to multicellular eukaryotic organisms, is true?

Accepted Answer

A)  By resulting in such diversity and complexity of life, it is an exception to the second law of thermodynamics. 
B)  It has occurred in accordance with the laws of thermodynamics and resulted in a substantial increase in the entropy of the planet. 
C)  It has occurred in accordance with the laws of thermodynamics and resulted in a substantial increase in the total energy in the universe. 
D)  It has occurred in accordance with the laws of thermodynamics and resulted in a substantial decrease in the entropy of the planet. 
A)  By resulting in such diversity and complexity of life, it is an exception to the second law of thermodynamics. 
B)  It has occurred in accordance with the laws of thermodynamics and resulted in a substantial increase in the entropy of the planet. 
C)  It has occurred in accordance with the laws of thermodynamics and resulted in a substantial increase in the total energy in the universe. 
D)  It has occurred in accordance with the laws of thermodynamics and resulted in a substantial decrease in the entropy of the planet.

Question 16

Use the following information to answer the question below.
 
The figure illustrates the energy states associated with the reaction A + B ↔ C + D. Which of the following represents the activation energy required for the enzyme-catalyzed reaction in the figure?

Accepted Answer

A)  a 
B)  b 
C)  c 
D)  d 
A)  a 
B)  b 
C)  c 
D)  d

Question 17

Which of the following statements describes the first law of thermodynamics?

Accepted Answer

A)  Energy cannot be created or destroyed. 
B)  The entropy of the universe is decreasing. 
C)  The entropy of the universe is constant. 
D)  Energy cannot be transferred or transformed. 
A)  Energy cannot be created or destroyed. 
B)  The entropy of the universe is decreasing. 
C)  The entropy of the universe is constant. 
D)  Energy cannot be transferred or transformed.

Question 18

In a metabolic pathway, succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, a substance that resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the amount of succinate molecules to those of malonic acid reduces the inhibitory effect of malonic acid. Which of the following statements correctly describes the role played by molecules described in the reaction?

Accepted Answer

A)  Succinate dehydrogenase is the enzyme, and fumarate is the substrate in the reaction. 
B)  Succinate dehydrogenase is the enzyme, and malonic acid is the substrate in the reaction. 
C)  Succinate is the substrate, and fumarate is the product in the reaction. 
D)  Fumarate is the product, and malonic acid is a noncompetitive inhibitor in the reaction. 
A)  Succinate dehydrogenase is the enzyme, and fumarate is the substrate in the reaction. 
B)  Succinate dehydrogenase is the enzyme, and malonic acid is the substrate in the reaction. 
C)  Succinate is the substrate, and fumarate is the product in the reaction. 
D)  Fumarate is the product, and malonic acid is a noncompetitive inhibitor in the reaction.

Question 19

Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as ________ is to ________.

Accepted Answer

A)  exergonic; spontaneous 
B)  exergonic; endergonic 
C)  free energy; entropy 
D)  work; energy 
A)  exergonic; spontaneous 
B)  exergonic; endergonic 
C)  free energy; entropy 
D)  work; energy

Question 20

Which of the following statements describes a common characteristic of catabolic pathways?

Accepted Answer

A)  They combine small molecules into larger, more energy-rich molecules. 
B)  They require energy from ATP hydrolysis to break down polymers into monomers. 
C)  They are endergonic and release energy that can be used for cellular work. 
D)  They are exergonic and provide energy that can be used to produce ATP from ADP and   ᵢ. 
A)  They combine small molecules into larger, more energy-rich molecules. 
B)  They require energy from ATP hydrolysis to break down polymers into monomers. 
C)  They are endergonic and release energy that can be used for cellular work. 
D)  They are exergonic and provide energy that can be used to produce ATP from ADP and   ᵢ.

Exam 8: An Introduction to Metabolism

Which of the following statements is true for a system at chemical equilibrium?

Use the following information to answer the question below. The figure illustrates the energy states associated with the reaction A + B ↔ C + D. Which of the following terms best describes the forward reaction in the figure?

Which of the following conditions may be overcome by increasing the substrate concentration in an enzymatic reaction with a fixed amount of enzyme?

During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a ∆G of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the ∆G for the new reaction?

Which of the following statements is an important consequence of the first law of thermodynamics for a living organism?

Chemical equilibrium is relatively rare in living cells because metabolic pathways are interconnected. Which of the following statements describes an example of a reaction that may be at chemical equilibrium in a cell?

A chemical reaction that has a positive ΔG is best described as ________.

Which of the following metabolic processes can occur without a net influx of energy from some other process?

Which of the following is an example of potential rather than kinetic energy?

Most cells cannot harness heat to perform work because

Which of the following characteristics is most likely to be associated with an enzyme that catalyzes two different chemical reactions?

Use the following information to answer the question below. Rate of an enzyme-catalyzed reaction as a function of varying reactant concentration, with the concentration of enzyme constant In the figure, why does the reaction rate plateau at higher reactant concentrations?

When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?

Which of the following statements about the evolution of life on Earth, from simple prokaryote-like cells to multicellular eukaryotic organisms, is true?

Use the following information to answer the question below. The figure illustrates the energy states associated with the reaction A + B ↔ C + D. Which of the following represents the activation energy required for the enzyme-catalyzed reaction in the figure?

Which of the following statements describes the first law of thermodynamics?

Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as ________ is to ________.

Which of the following statements describes a common characteristic of catabolic pathways?

Evolution, the Themes of Biology, and Scientific Inquiry

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

Cellular Respiration and Fermentation

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

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Viruses

DNA Tools and 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

Vascular 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

Filters

Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as is to .