Question 1

Which of the following statements best summarizes an important consequence of the first law of thermodynamics for living organisms?

Accepted Answer

A)  The energy content of a single organism is constant. 
B)  Each 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)  An organism grows by converting energy into organic matter. 
A)  The energy content of a single organism is constant. 
B)  Each 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)  An organism grows by converting energy into organic matter. B

Question 2

An enzyme-catalyzed reaction has a ∆G of -20 kcal/mol under standard conditions. What will be the ∆G for the reaction if the amount of enzyme is doubled?

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 B

Question 3

Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics?

Accepted Answer

A)  Living organisms do not obey the second law of thermodynamics, which states that the entropy of an organism increases with each energy transformation. 
B)  As a consequence of the processes required for growth, the decrease in entropy of the organism is associated with a corresponding increase in the entropy of the universe. 
C)  As a consequence of the processes required for growth, the decrease in entropy of the organism is associated with a corresponding decrease in the entropy of the universe. 
D)  Living organisms are able to transform chemical energy into entropy. 
A)  Living organisms do not obey the second law of thermodynamics, which states that the entropy of an organism increases with each energy transformation. 
B)  As a consequence of the processes required for growth, the decrease in entropy of the organism is associated with a corresponding increase in the entropy of the universe. 
C)  As a consequence of the processes required for growth, the decrease in entropy of the organism is associated with a corresponding decrease in the entropy of the universe. 
D)  Living organisms are able to transform chemical energy into entropy. B

Question 4

The relationship between the breakdown of macromolecules and the biosynthesis of macromolecules is most similar to the relationship between which of the following pairs of terms?

Accepted Answer

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

Question 5

If an enzyme is added to a solution where its substrate and product are in equilibrium, what will occur?

Accepted Answer

A)  Additional substrate will be formed. 
B)  The reaction will change from endergonic to exergonic. 
C)  The free energy of the system will change. 
D)  Nothing; the reaction will stay at equilibrium. 
A)  Additional substrate will be formed. 
B)  The reaction will change from endergonic to exergonic. 
C)  The free energy of the system will change. 
D)  Nothing; the reaction will stay at equilibrium.

Question 6

Which of the following statements best describes induced fit?

Accepted Answer

A)  Substrate binds to an allosteric site rather than to the active site of an enzyme. 
B)  Binding of an activator molecule changes the shape of the active site of an enzyme. 
C)  The conformation of the active site is determined by the tertiary or quaternary structure of the enzyme. 
D)  Binding of substrate to the active site changes the shape of the active site of an enzyme. 
A)  Substrate binds to an allosteric site rather than to the active site of an enzyme. 
B)  Binding of an activator molecule changes the shape of the active site of an enzyme. 
C)  The conformation of the active site is determined by the tertiary or quaternary structure of the enzyme. 
D)  Binding of substrate to the active site changes the shape of the active site of an enzyme.

Question 7

Which of the following statements best describes how addition of a catalyst will affect a chemical reaction?

Accepted Answer

A)  The catalyzed reaction will have a lower ∆G than the uncatalyzed reaction. 
B)  The catalyzed reaction will have the same ∆G as the uncatalyzed reaction. 
C)  The catalyzed reaction will have a higher ∆G than the uncatalyzed reaction. 
D)  The catalyzed reaction will consume all of the catalyst. 
A)  The catalyzed reaction will have a lower ∆G than the uncatalyzed reaction. 
B)  The catalyzed reaction will have the same ∆G as the uncatalyzed reaction. 
C)  The catalyzed reaction will have a higher ∆G than the uncatalyzed reaction. 
D)  The catalyzed reaction will consume all of the catalyst.

Question 8

Which of the following statements best describes a primary mechanism by which the energy released in ATP hydrolysis is used directly to drive endergonic chemical reactions in a cell?

Accepted Answer

A)  Free energy is released as heat, which speeds up the rate of endergonic reactions. 
B)  The released phosphate is used to form phosphorylated intermediates that are more reactive than the original unphosphorylated substrate. 
C)  Binding of ATP to an enzyme active site converts an endergonic reaction to an exergonic reaction. 
D)  The phosphate is combined with ADP to regenerate ATP. 
A)  Free energy is released as heat, which speeds up the rate of endergonic reactions. 
B)  The released phosphate is used to form phosphorylated intermediates that are more reactive than the original unphosphorylated substrate. 
C)  Binding of ATP to an enzyme active site converts an endergonic reaction to an exergonic reaction. 
D)  The phosphate is combined with ADP to regenerate ATP.

Question 9

Which of the following statements best summarizes the figure above?

Accepted Answer

A)  Energy from catabolism can be used directly for performing cellular work. 
B)  ADP +   i are molecules that store energy for catabolism. 
C)  ATP is a molecule that acts as an intermediary to store energy for cellular work. 
D)    i acts as a shuttle molecule to move energy from ATP to ADP. 
A)  Energy from catabolism can be used directly for performing cellular work. 
B)  ADP +   i are molecules that store energy for catabolism. 
C)  ATP is a molecule that acts as an intermediary to store energy for cellular work. 
D)    i acts as a shuttle molecule to move energy from ATP to ADP.

Question 10

Which of the following types of reactions would decrease the entropy within a cell?

Accepted Answer

A)  anabolic reactions 
B)  hydrolysis 
C)  digestion 
D)  catabolic reactions 
A)  anabolic reactions 
B)  hydrolysis 
C)  digestion 
D)  catabolic reactions

Question 11

What is the name of the barrier that must be overcome before products are formed in a spontaneous reaction?

Accepted Answer

A)  entropy 
B)  activation energy 
C)  the equilibrium point 
D)  free energy 
A)  entropy 
B)  activation energy 
C)  the equilibrium point 
D)  free energy

Question 12

A series of enzymes catalyze the reactions in the metabolic pathway X → Y → Z → A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. Based on its interaction with the enzyme that converts X to Y substance A is best described as ________.

Accepted Answer

A)  an allosteric inhibitor 
B)  a substrate 
C)  a metabolic intermediate 
D)  a competitive inhibitor 
A)  an allosteric inhibitor 
B)  a substrate 
C)  a metabolic intermediate 
D)  a competitive inhibitor

Question 13

Which of the following statements best describes a relationship between the evolution of multicellular life on Earth and the laws of thermodynamics?

Accepted Answer

A)  Evolution represents a rare exception to the second law of thermodynamics because it has resulted in such a vast diversity of complex organisms. 
B)  Evolution has occurred in accordance with the laws of thermodynamics and resulted in a decrease in the entropy of the universe. 
C)  Evolution has occurred in accordance with the laws of thermodynamics and resulted in a substantial increase in the total energy in the universe. 
D)  Evolution has occurred in accordance with the laws of thermodynamics and resulted in an increase in the entropy of the universe. 
A)  Evolution represents a rare exception to the second law of thermodynamics because it has resulted in such a vast diversity of complex organisms. 
B)  Evolution has occurred in accordance with the laws of thermodynamics and resulted in a decrease in the entropy of the universe. 
C)  Evolution has occurred in accordance with the laws of thermodynamics and resulted in a substantial increase in the total energy in the universe. 
D)  Evolution has occurred in accordance with the laws of thermodynamics and resulted in an increase in the entropy of the universe.

Question 14

The figure presents a model of the ATP cycle in a cell. Which labeled section of the model represents the point at which ATP hydrolysis occurs?

Accepted Answer

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

Question 15

Which of the following statements best 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 there is no change in the net concentrations of reactants or products 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 there is no change in the net concentrations of reactants or products 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 16

The mathematical expression for the change in free energy of a system is ΔG = ΔH - TΔS. Which of the following statements best describes a term in this equation?

Accepted Answer

A)  ΔS is the change in enthalpy, a measure of randomness. 
B)  ΔH is the change in entropy, the energy available to do work. 
C)  ΔG is the change in free energy. 
D)  T is the temperature in degrees Celsius. 
A)  ΔS is the change in enthalpy, a measure of randomness. 
B)  ΔH is the change in entropy, the energy available to do work. 
C)  ΔG is the change in free energy. 
D)  T is the temperature in degrees Celsius.

Question 17

Which of the following statements is the reason that most cells cannot harness heat to perform work?

Accepted Answer

A)  heat is not a form of energy 
B)  temperature is usually uniform throughout a cell 
C)  heat can never be used to do work 
D)  heat must remain constant during work 
A)  heat is not a form of energy 
B)  temperature is usually uniform throughout a cell 
C)  heat can never be used to do work 
D)  heat must remain constant during work

Question 18

Which of the following statements best describes enzyme function?

Accepted Answer

A)  Enzyme function is generally increased if the 3-D structure or conformation of an enzyme is altered. 
B)  Enzyme function is independent of physical and chemical environmental factors such as pH and temperature. 
C)  Enzymes increase the rate of chemical reactions by lowering activation energy barriers. 
D)  Enzymes increase the rate of chemical reactions by stimulating ATP hydrolysis. 
A)  Enzyme function is generally increased if the 3-D structure or conformation of an enzyme is altered. 
B)  Enzyme function is independent of physical and chemical environmental factors such as pH and temperature. 
C)  Enzymes increase the rate of chemical reactions by lowering activation energy barriers. 
D)  Enzymes increase the rate of chemical reactions by stimulating ATP hydrolysis.

Question 19

A decrease in entropy is associated with which of the following types of reaction?

Accepted Answer

A)  dehydration 
B)  catabolic 
C)  depolymerization 
D)  hydrolysis 
A)  dehydration 
B)  catabolic 
C)  depolymerization 
D)  hydrolysis

Question 20

In the citric acid cycle, succinate dehydrogenase catalyzes the conversion of succinate to fumarate. This reaction is inhibited by malonate, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Which of the following statements best 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 malonate 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 malonate 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 malonate 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 malonate is a noncompetitive inhibitor in the reaction.

Exam 6: Energy and Life

Which of the following statements best summarizes an important consequence of the first law of thermodynamics for living organisms?

An enzyme-catalyzed reaction has a ∆G of -20 kcal/mol under standard conditions. What will be the ∆G for the reaction if the amount of enzyme is doubled?

Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics?

The relationship between the breakdown of macromolecules and the biosynthesis of macromolecules is most similar to the relationship between which of the following pairs of terms?

If an enzyme is added to a solution where its substrate and product are in equilibrium, what will occur?

Which of the following statements best describes induced fit?

Which of the following statements best describes how addition of a catalyst will affect a chemical reaction?

Which of the following statements best describes a primary mechanism by which the energy released in ATP hydrolysis is used directly to drive endergonic chemical reactions in a cell?

Which of the following statements best summarizes the figure above?

Which of the following types of reactions would decrease the entropy within a cell?

What is the name of the barrier that must be overcome before products are formed in a spontaneous reaction?

Which of the following statements best describes a relationship between the evolution of multicellular life on Earth and the laws of thermodynamics?

The figure presents a model of the ATP cycle in a cell. Which labeled section of the model represents the point at which ATP hydrolysis occurs?

Which of the following statements best describes an example of a reaction that may be at chemical equilibrium in a cell?

The mathematical expression for the change in free energy of a system is ΔG = ΔH - TΔS. Which of the following statements best describes a term in this equation?

Which of the following statements is the reason that most cells cannot harness heat to perform work?

Which of the following statements best describes enzyme function?

A decrease in entropy is associated with which of the following types of reaction?

Biology and Its Themes

Atoms and Molecules

The Chemistry of Water

Carbon: the Basis of Molecular Diversity

Biological Macromolecules and Lipids

Cell Structure and Function

Cell Membranes

Cellular Signaling

Cell Respiration

Photosynthetic Processes

Mitosis

Sexual Life Cycles and Meiosis

Mendelian Genetics

Linkage and Chromosomes

Nucleic Acids and Inheritance

Expression of Genes

Control of Gene Expression

Dna Technology

The Evolution of Genomes

How Evolution Works

Phylogenetic Reconstruction

Microevolution

Species and Speciation

Macroevolution

Introduction to Viruses

Prokaryotes

The Origin and Evolution of Eukaryotes

Nonvascular and Seedless Vascular Plants

Seed Plants

Introduction to Fungi

An Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure and Growth

Transport in Vascular Plants

Plant Nutrition

Reproduction of Flowering Plants

Plant Signals and Behavior

The Animal Body

Chemical Signals in Animals

Animal Digestive Systems

Animal Transport Systems

Animal Excretory Systems

Animal Reproductive Systems

Development in Animals

Animal Defenses Against Infection

Electrical Signals in Animals

Neural Regulation in Animals

Sensation and Movement in Animals

An Overview of Ecology

Behavioral Ecology

Populations and Life History Traits

Biodiversity and Communities

Energy Flow and Chemical Cycling in Ecosystems

Conservation and Global Ecology

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