Question 1

What features of an enzyme's active site allow it to recognize and bind a substrate?

Accepted Answer

A)  The active site shape is specific for the substrate. 
B)  The active site shape is specific for the products. 
C)  The active site is highly versatile and can bind a wide variety of molecules. 
D)  The active site is buried deep within a hydrophobic region of the enzyme. 
E)  The active site has a different shape than the substrate. 
A)  The active site shape is specific for the substrate. 
B)  The active site shape is specific for the products. 
C)  The active site is highly versatile and can bind a wide variety of molecules. 
D)  The active site is buried deep within a hydrophobic region of the enzyme. 
E)  The active site has a different shape than the substrate.

Question 2

It is estimated that approximately 90 percent of energy that passes between levels in a food web is lost at each level.Explain the first law of thermodynamics, and discuss why this apparent loss of energy does not contradict that law.

Accepted Answer

The first law of thermodynamics states t

Question 3

Denatured enzymes are

Accepted Answer

A)  ribozymes. 
B)  synthesized in vitro. 
C)  allosteric enzymes. 
D)  nonfunctional enzymes. 
E)  converted to coenzymes. 
A)  ribozymes. 
B)  synthesized in vitro. 
C)  allosteric enzymes. 
D)  nonfunctional enzymes. 
E)  converted to coenzymes.

Question 4

Refer to the figure below.   Based on the graph, which statement best describes these chemical reactions?

Accepted Answer

A)  Addition of a catalyst to a reaction does not affect the equilibrium position of the reaction, but only increases the rate of attainment of equilibrium. 
B)  Addition of a catalyst to a reaction speeds up the reaction by decreasing the amount of energy input needed to get over the activation energy barrier. 
C)  Addition of heat to a reaction speeds up the reaction by increasing the kinetic energy of reactant molecules, which increases collisions that result in products. 
D)  Addition of energy must be made to exergonic reactions in order to allow reactants to achieve the transition state that can then proceed spontaneously to form products. 
E)  Addition of energy to an endergonic reaction above that needed to go from reactants to products must be made in order to allow reactants to achieve the transition state. 
A)  Addition of a catalyst to a reaction does not affect the equilibrium position of the reaction, but only increases the rate of attainment of equilibrium. 
B)  Addition of a catalyst to a reaction speeds up the reaction by decreasing the amount of energy input needed to get over the activation energy barrier. 
C)  Addition of heat to a reaction speeds up the reaction by increasing the kinetic energy of reactant molecules, which increases collisions that result in products. 
D)  Addition of energy must be made to exergonic reactions in order to allow reactants to achieve the transition state that can then proceed spontaneously to form products. 
E)  Addition of energy to an endergonic reaction above that needed to go from reactants to products must be made in order to allow reactants to achieve the transition state.

Question 5

Refer to the figures below.   These figures can be used to illustrate the first and second laws of thermodynamics.Assign each figure to one of these laws, then explain the difference between the figures.

Accepted Answer

Figure 1 illustrates the first law and F

Question 6

In solution, ATP is readily hydrolyzed into

Accepted Answer

A)  ribose and three phosphate ions. 
B)  ADP and one phosphate ion. 
C)  AMP and two pyrophosphate ions. 
D)  ADP and adenosine. 
E)  adenine and three phosphate ions. 
A)  ribose and three phosphate ions. 
B)  ADP and one phosphate ion. 
C)  AMP and two pyrophosphate ions. 
D)  ADP and adenosine. 
E)  adenine and three phosphate ions.

Question 7

An inhibitor that binds reversibly to the active site is termed a(n) _______ inhibitor, whereas an inhibitor that binds reversibly to the enzyme-substrate complex is termed a(n) _______ inhibitor.

Accepted Answer

A)  competitive; noncompetitive 
B)  competitive; uncompetitive 
C)  uncompetitive; competitive 
D)  noncompetitive; uncompetitive 
E)  uncompetitive; noncompetitive 
A)  competitive; noncompetitive 
B)  competitive; uncompetitive 
C)  uncompetitive; competitive 
D)  noncompetitive; uncompetitive 
E)  uncompetitive; noncompetitive

Question 8

Which are biological examples of potential energy (PE) and kinetic energy (KE)?

Accepted Answer

A)  PE = concentration gradient; KE = chemical bonds 
B)  PE = muscle contraction; KE = electrical charge imbalance 
C)  PE = chemical bonds; KE = ion movement across a membrane 
D)  PE = electrical charge imbalance; KE = concentration gradient 
E)  PE = protein conformational change; KE = muscle contraction 
A)  PE = concentration gradient; KE = chemical bonds 
B)  PE = muscle contraction; KE = electrical charge imbalance 
C)  PE = chemical bonds; KE = ion movement across a membrane 
D)  PE = electrical charge imbalance; KE = concentration gradient 
E)  PE = protein conformational change; KE = muscle contraction

Question 9

Refer to the figure below.   Which type of mechanism used by an enzyme to catalyze a reaction is illustrated in the figure?

Accepted Answer

A)  Covalent catalysis 
B)  Acid-base catalysis 
C)  Metal ion catalysis 
D)  Induced fit 
E)  Induced strain 
A)  Covalent catalysis 
B)  Acid-base catalysis 
C)  Metal ion catalysis 
D)  Induced fit 
E)  Induced strain

Question 10

Refer to the expression and table below.     The enzyme tryptophanase catalyzes the reaction shown.However, research has revealed that compounds other than tryptophan can act as substrates for this enzyme.Some of these compounds are listed in the table along with their dissociation constants.What does the information in the table indicate about the affinity of the enzyme for compounds other than its natural substrate, tryptophan?

Accepted Answer

The results indicate that all but one of

Question 11

Glycogen is a large molecule consisting of hundreds of molecules of glucose bonded together, and thus plays an energy storage role in animal cells.The chemical reaction that adds glucose units onto a glycogen molecule is an example of a(n) _______ reaction in the cell's metabolism.

Accepted Answer

The answer of Glycogen is a large molecule consisting of...

Question 12

When energy is converted from one form to another, only some of the energy is usable.The unusable energy is released to a form associated with disorder.A measure of this disorder is referred to as

Accepted Answer

A)  free energy. 
B)  entropy. 
C)  enthalpy. 
D)  thermodynamics. 
E)  equilibrium. 
A)  free energy. 
B)  entropy. 
C)  enthalpy. 
D)  thermodynamics. 
E)  equilibrium.

Question 13

Refer to the figure below.   Portions of three biosynthetic pathways regulated through feedback inhibition and activation are shown.Two of these pathways intersect at carbamoyl phosphate.The third pathway generates a product that activates production of carbamoyl phosphate through allosteric modification of the enzyme carbamoyl phosphate synthetase.In this set of pathways, arginine biosynthesis is shut down through feedback inhibition when _______ and arginine reach high levels of concentration.

Accepted Answer

The answer of Refer to the figure below.  ...

Question 14

Enzymes function as biological _______.

Accepted Answer

The answer of Enzymes function as biological _______....

Question 15

Refer to the figure below.   The figure illustrates how _______ of a key enzyme in a metabolic pathway can shift the flow of molecules into a different pathway.

Accepted Answer

The answer of Refer to the figure below.  ...

Question 16

The first law of thermodynamics states that the total energy in the universe is

Accepted Answer

A)  decreasing. 
B)  increasing. 
C)  constant. 
D)  being converted to free energy. 
E)  being converted to matter. 
A)  decreasing. 
B)  increasing. 
C)  constant. 
D)  being converted to free energy. 
E)  being converted to matter.

Question 17

In some cases, a substrate-enzyme complex is stabilized by

Accepted Answer

A)  peptide bonds. 
B)  disulfide bonds. 
C)  ester bonds. 
D)  hydrogen bonds. 
E)  phosphate bonds. 
A)  peptide bonds. 
B)  disulfide bonds. 
C)  ester bonds. 
D)  hydrogen bonds. 
E)  phosphate bonds.

Question 18

Consider two enzyme reaction solutions.Solution 1 has a ratio of enzyme to substrate of 1:100.Solution 2 has a ratio of enzyme to substrate of 100:1.Both solutions contain the same quantity of enzyme.Which reaction gives the greater reaction rate, and why?

Accepted Answer

A)  Solution 1, because the enzyme has much more available substrate than in solution 2. 
B)  Solution 1, because the enzyme has much less available substrate than in solution 2. 
C)  Solution 2, because the enzyme is saturated in this solution but not in solution 1. 
D)  Solution 2, because the enzyme is not saturated in this solution but is saturated in solution 1. 
E)  Both have the same reaction rate, because they contain the same quantity of enzyme. 
A)  Solution 1, because the enzyme has much more available substrate than in solution 2. 
B)  Solution 1, because the enzyme has much less available substrate than in solution 2. 
C)  Solution 2, because the enzyme is saturated in this solution but not in solution 1. 
D)  Solution 2, because the enzyme is not saturated in this solution but is saturated in solution 1. 
E)  Both have the same reaction rate, because they contain the same quantity of enzyme.

Question 19

Refer to the table below.   Of the four reactions listed in the table, the one that is spontaneous under all temperature conditions is reaction _______.

Accepted Answer

The answer of Refer to the table below.  ...

Question 20

Refer to the figure below.   The figure shows activities at the active site of the enzyme hexokinase as it catalyzes a reaction between ATP and glucose.Based on this figure, it can be inferred that the magnesium ion functions to _______ the ATP molecule so it can be attacked by glucose.

Accepted Answer

The answer of Refer to the figure below.  ...

Exam 8: Energy, Enzymes, and Metabolism

What features of an enzyme's active site allow it to recognize and bind a substrate?

It is estimated that approximately 90 percent of energy that passes between levels in a food web is lost at each level.Explain the first law of thermodynamics, and discuss why this apparent loss of energy does not contradict that law.

Denatured enzymes are

Refer to the figure below. Based on the graph, which statement best describes these chemical reactions?

Refer to the figures below. These figures can be used to illustrate the first and second laws of thermodynamics.Assign each figure to one of these laws, then explain the difference between the figures.

In solution, ATP is readily hydrolyzed into

An inhibitor that binds reversibly to the active site is termed a(n) _______ inhibitor, whereas an inhibitor that binds reversibly to the enzyme-substrate complex is termed a(n) _______ inhibitor.

Which are biological examples of potential energy (PE) and kinetic energy (KE)?

Refer to the figure below. Which type of mechanism used by an enzyme to catalyze a reaction is illustrated in the figure?

Glycogen is a large molecule consisting of hundreds of molecules of glucose bonded together, and thus plays an energy storage role in animal cells.The chemical reaction that adds glucose units onto a glycogen molecule is an example of a(n) _______ reaction in the cell's metabolism.

When energy is converted from one form to another, only some of the energy is usable.The unusable energy is released to a form associated with disorder.A measure of this disorder is referred to as

Enzymes function as biological _______.

Refer to the figure below. The figure illustrates how _______ of a key enzyme in a metabolic pathway can shift the flow of molecules into a different pathway.

The first law of thermodynamics states that the total energy in the universe is

In some cases, a substrate-enzyme complex is stabilized by

Consider two enzyme reaction solutions.Solution 1 has a ratio of enzyme to substrate of 1:100.Solution 2 has a ratio of enzyme to substrate of 100:1.Both solutions contain the same quantity of enzyme.Which reaction gives the greater reaction rate, and why?

Refer to the table below. Of the four reactions listed in the table, the one that is spontaneous under all temperature conditions is reaction _______.

Refer to the figure below. The figure shows activities at the active site of the enzyme hexokinase as it catalyzes a reaction between ATP and glucose.Based on this figure, it can be inferred that the magnesium ion functions to _______ the ATP molecule so it can be attacked by glucose.

Studying Life

Small Molecules and the Chemistry of Life

Proteins, Carbohydrates, and Lipids

Nucleic Acids and the Origin of Life

Cells: the Working Units of Life

Cell Membranes

Cell Communication and Multicellularity

Pathways That Harvest Chemical Energy

Photosynthesis: Energy From Sunlight

The Cell Cycle and Cell Division

Inheritance, Genes, and Chromosomes

Dna and Its Role in Heredity

From Dna to Protein: Gene Expression

Gene Mutation and Molecular Medicine

Regulation of Gene Expression

Genomes

Recombinant Dna and Biotechnology

Mechanisms of Evolution

Reconstructing and Using Phylogenies

Speciation

Evolution of Genes and Genomes

The History of Life on Earth

Bacteria, Archaea, and Viruses

The Origin and Diversification of Eukaryotes

Plants Without Seeds: From Water to Land

The Evolution of Seed Plants

The Evolution and Diversity of Fungi

Animal Origins and the Evolution of Body Plans

Protostome Animals

Deuterostome Animals

The Plant Body

Transport in Plants

Plant Nutrition

Regulation of Plant Growth

Reproduction in Flowering Plants

Plant Responses to Environmental Challenges

Physiology, Homeostasis, and Temperature Regulation

Animal Hormones

Immunology: Animal Defense Systems

Animal Reproduction

Animal Development

Neurons, Glia, and Nervous Systems

Sensory Systems

The Mammalian Nervous System: Structure and Higher Functions

Musculoskeletal Systems

Gas Exchange

Circulatory Systems

Nutrition, Digestion, and Absorption

Salt and Water Balance and Nitrogen Excretion

Animal Behavior

The Physical Environment and Biogeography of Life

Populations

Species Interactions

Communities

Ecosystems

A Changing Biosphere

Filters

An inhibitor that binds reversibly to the active site is termed a(n) _ inhibitor, whereas an inhibitor that binds reversibly to the enzyme-substrate complex is termed a(n) _ inhibitor.