Question 1

The hydrolysis of sucrose into glucose and fructose by the enzyme sucrase

Accepted Answer

A)  increases entropy. 
B)  is endergonic, leading to a decrease in temperature. 
C)  is an example of anabolism. 
D)  consumes free energy. 
E)  will have a F1F1F1S1F1F1F10G = 0 due to the presence of sucrose. 
A)  increases entropy. 
B)  is endergonic, leading to a decrease in temperature. 
C)  is an example of anabolism. 
D)  consumes free energy. 
E)  will have a F1F1F1S1F1F1F10G = 0 due to the presence of sucrose.

Question 2

When ADP gains a phosphate to form ATP,

Accepted Answer

A)  free energy is released by the loss of a phosphate. 
B)  the reaction ends. 
C)  energy is absorbed. 
D)  chemical energy is converted to light energy. 
E)  ribose loses an oxygen to become deoxyribose. 
A)  free energy is released by the loss of a phosphate. 
B)  the reaction ends. 
C)  energy is absorbed. 
D)  chemical energy is converted to light energy. 
E)  ribose loses an oxygen to become deoxyribose.

Question 3

Refer to the figure below.   This figure shows an example of a biological molecule that can function as an enzyme.This type of enzyme is called a ribozyme because it consists of a molecule of _______.

Accepted Answer

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

Question 4

Enzymes are biological catalysts and function by

Accepted Answer

A)  increasing the free energy in a system. 
B)  lowering the activation energy of a reaction. 
C)  lowering entropy in a system. 
D)  increasing the temperature near a reaction. 
E)  altering the equilibrium of a reaction. 
A)  increasing the free energy in a system. 
B)  lowering the activation energy of a reaction. 
C)  lowering entropy in a system. 
D)  increasing the temperature near a reaction. 
E)  altering the equilibrium of a reaction.

Question 5

Refer to the table below.   Information about two reactions is provided.From this information, it can be stated that reaction _______ is exergonic because its F1F1F1S1F1F1F10G° is _______.

Accepted Answer

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

Question 6

Which statement regarding allosterically regulated enzymes is valid?

Accepted Answer

A)  Allosterically regulated enzymes often have more than one subunit. 
B)  An allosteric enzyme is locked in a rigid conformation, indicating that it cannot use induced-fit mechanisms for catalyzing reactions. 
C)  The allosteric regulatory sites overlap with the active site in an allosteric enzyme. 
D)  Unlike substrate binding, the binding of molecules to allosteric sites in an allosteric enzyme is nonspecific. 
E)  The only type of effect of an allosteric molecule on an allosteric enzyme is an inhibitory effect. 
A)  Allosterically regulated enzymes often have more than one subunit. 
B)  An allosteric enzyme is locked in a rigid conformation, indicating that it cannot use induced-fit mechanisms for catalyzing reactions. 
C)  The allosteric regulatory sites overlap with the active site in an allosteric enzyme. 
D)  Unlike substrate binding, the binding of molecules to allosteric sites in an allosteric enzyme is nonspecific. 
E)  The only type of effect of an allosteric molecule on an allosteric enzyme is an inhibitory effect.

Question 7

Refer to the figure and table below.     A student is constructing a table that lists poisons whose mechanisms of action involve enzyme inhibition. She will put a checkmark in any column that characterizes a compound's mode of inhibition.Arsenate acts to inhibit many enzymes that use ATP as a coenzyme.To complete this row in the table the student should check the box(es) under _______.

Accepted Answer

reversible

Question 8

Which statement is not true about enzymes?

Accepted Answer

A)  Enzymes orient substrates into positions that optimize chemical reactions between them. 
B)  An enzyme may cause physical strain in a substrate once the substrate has bound to the enzyme's active site. 
C)  Enzymes can use acid-base chemistry to destabilize bonds in substrates. 
D)  An enzyme can form a temporary covalent intermediate with a substrate as part of the catalytic mechanism. 
E)  Enzymes can shift the position of equilibrium to favor products. 
A)  Enzymes orient substrates into positions that optimize chemical reactions between them. 
B)  An enzyme may cause physical strain in a substrate once the substrate has bound to the enzyme's active site. 
C)  Enzymes can use acid-base chemistry to destabilize bonds in substrates. 
D)  An enzyme can form a temporary covalent intermediate with a substrate as part of the catalytic mechanism. 
E)  Enzymes can shift the position of equilibrium to favor products.

Question 9

The enzymes catalase and malate dehydrogenase are both classified as oxidoreductases.Catalase has a heme group present at its catalytic site, whereas malate dehydrogenase has no bound cofactors or prosthetic groups and uses NAD+ as a coenzyme.What can you infer about these two enzymes?

Accepted Answer

A)  Both use the same mechanism to transfer electrons during an oxidation-reduction reaction. 
B)  One uses induced fit to facilitate transfer of electrons from one group to another, while the other does not. 
C)  One uses specific binding sites to orient the substrate for electron transfer, while the other does not. 
D)  One uses covalent catalysis, while the other uses acid-base catalysis to transfer electrons. 
E)  One uses metal ion catalysis, while the other uses a nonmetal group to transfer electrons. 
A)  Both use the same mechanism to transfer electrons during an oxidation-reduction reaction. 
B)  One uses induced fit to facilitate transfer of electrons from one group to another, while the other does not. 
C)  One uses specific binding sites to orient the substrate for electron transfer, while the other does not. 
D)  One uses covalent catalysis, while the other uses acid-base catalysis to transfer electrons. 
E)  One uses metal ion catalysis, while the other uses a nonmetal group to transfer electrons.

Question 10

Refer to the table below listing facts about the compound oligomycin.   Which two facts taken together support the claim that cells convert the chemical energy of ATP into other forms of energy?

Accepted Answer

A)  2 and 5 
B)  1 and 4 
C)  2 and 3 
D)  3 and 5 
E)  3 and 4 
A)  2 and 5 
B)  1 and 4 
C)  2 and 3 
D)  3 and 5 
E)  3 and 4

Question 11

Glyceraldehyde 3-phosphate dehydrogenase catalyzes the reaction between glyceraldehyde 3-phosphate, NAD+, and phosphate ion to form 1,3-bisphosphoglycerate and NADH.Under certain conditions, a permanently radiolabeled enzyme intermediate forms if 14C-glyceraldehyde 3-phosphate and NAD+ are used as substrates and phosphate is left out of the reaction mix.The radiolabeled molecule is linked to a cysteine side chain of the enzyme.This result suggests that this enzyme uses _______ as a catalytic mechanism.

Accepted Answer

Question 12

Refer to the table below.   Hexokinase catalyzes the reaction between glucose and ATP to form glucose 6-phosphate and ADP.The table summarizes results of experiments using purified hexokinase.In the experiments, different sugars were substituted for glucose, and the rate of each catalytic reaction was measured and divided by the rate of reaction using glucose as substrate.These data provide evidence for which general statement that has been made about enzymes?

Accepted Answer

A)  Enzymes are able to speed up a reaction by lowering its activation energy. 
B)  Enzymes display high specificity with respect to their substrates. 
C)  Enzymes often require cofactors and/or coenzymes in addition to their substrates. 
D)  Enzymes bind substrates at their active sites using noncovalent forces of attraction. 
E)  Enzymes lower activation energy of a reaction by stabilizing the substrate's transition state. 
A)  Enzymes are able to speed up a reaction by lowering its activation energy. 
B)  Enzymes display high specificity with respect to their substrates. 
C)  Enzymes often require cofactors and/or coenzymes in addition to their substrates. 
D)  Enzymes bind substrates at their active sites using noncovalent forces of attraction. 
E)  Enzymes lower activation energy of a reaction by stabilizing the substrate's transition state.

Question 13

Many enzymes require small nonprotein molecules for a reaction to occur.These molecules temporarily bind to and then are released from the substrate before participating in other reactions.These types of molecules are called

Accepted Answer

A)  side chains. 
B)  coenzymes. 
C)  substrates. 
D)  prosthetic groups. 
E)  cofactors. 
A)  side chains. 
B)  coenzymes. 
C)  substrates. 
D)  prosthetic groups. 
E)  cofactors.

Question 14

The breakdown of carbohydrates in a cell could provide a source of energy used in

Accepted Answer

A)  catabolism of proteins. 
B)  breaking down polynucleic acids. 
C)  anabolism of lipids. 
D)  the conversion of ATP to ADP. 
E)  an exothermic reaction. 
A)  catabolism of proteins. 
B)  breaking down polynucleic acids. 
C)  anabolism of lipids. 
D)  the conversion of ATP to ADP. 
E)  an exothermic reaction.

Question 15

Which part of an enzyme molecule may function as a direct participant in the chemical reaction it catalyzes?

Accepted Answer

A)  Alpha carbons of amino acids 
B)  Peptide bonds 
C)  Amino acid side chains 
D)  Carboxyl groups of the polypeptide backbone 
E)  Amine groups of the polypeptide backbone 
A)  Alpha carbons of amino acids 
B)  Peptide bonds 
C)  Amino acid side chains 
D)  Carboxyl groups of the polypeptide backbone 
E)  Amine groups of the polypeptide backbone

Question 16

Refer to the figure below.   This is an important equilibrium system in aquatic environments, particularly in the oceans.Which statement correctly describes a reaction of this system in response to an environmental change?

Accepted Answer

A)  A decrease in carbonic acid shifts the equilibrium to the left. 
B)  An increase in carbon dioxide shifts the equilibrium to the right. 
C)  Adding carbonic acid has no effect on the system. 
D)  Removal of carbon dioxide shifts the equilibrium to the right. 
E)  Adding carbonic acid and removing carbon dioxide simultaneously has no effect on the system. 
A)  A decrease in carbonic acid shifts the equilibrium to the left. 
B)  An increase in carbon dioxide shifts the equilibrium to the right. 
C)  Adding carbonic acid has no effect on the system. 
D)  Removal of carbon dioxide shifts the equilibrium to the right. 
E)  Adding carbonic acid and removing carbon dioxide simultaneously has no effect on the system.

Question 17

Enzymes of the acid-base catalysis type contain

Accepted Answer

A)  a metal ion bound to a side chain. 
B)  a prosthetic group. 
C)  a coenzyme. 
D)  acidic or basic amino acid side chains (R groups) in the active site. 
E)  a covalently activated active site. 
A)  a metal ion bound to a side chain. 
B)  a prosthetic group. 
C)  a coenzyme. 
D)  acidic or basic amino acid side chains (R groups) in the active site. 
E)  a covalently activated active site.

Question 18

Plot free energy versus the time course of an endergonic reaction, and do the same for an exergonic reaction.Include the activation energy on both plots.Label Ea and F1F1F1S1F1F1F10G on both graphs.

Accepted Answer

Question 19

Refer to the graph below.   The graph shows data collected using a purified enzyme to catalyze a reaction.Magnesium ion likely functions as a _______ in this reaction.

Accepted Answer

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

Question 20

Heat, light, electricity, and motion are all examples of _______ energy.

Accepted Answer

The answer of Heat, light, electricity, and motion are all...

Exam 8: Energy, Enzymes, and Metabolism

The hydrolysis of sucrose into glucose and fructose by the enzyme sucrase

When ADP gains a phosphate to form ATP,

Refer to the figure below. This figure shows an example of a biological molecule that can function as an enzyme.This type of enzyme is called a ribozyme because it consists of a molecule of _______.

Enzymes are biological catalysts and function by

Refer to the table below. Information about two reactions is provided.From this information, it can be stated that reaction _______ is exergonic because its G° is _______.

Which statement regarding allosterically regulated enzymes is valid?

Which statement is not true about enzymes?

The enzymes catalase and malate dehydrogenase are both classified as oxidoreductases.Catalase has a heme group present at its catalytic site, whereas malate dehydrogenase has no bound cofactors or prosthetic groups and uses NAD+ as a coenzyme.What can you infer about these two enzymes?

Refer to the table below listing facts about the compound oligomycin. Which two facts taken together support the claim that cells convert the chemical energy of ATP into other forms of energy?

Many enzymes require small nonprotein molecules for a reaction to occur.These molecules temporarily bind to and then are released from the substrate before participating in other reactions.These types of molecules are called

The breakdown of carbohydrates in a cell could provide a source of energy used in

Which part of an enzyme molecule may function as a direct participant in the chemical reaction it catalyzes?

Refer to the figure below. This is an important equilibrium system in aquatic environments, particularly in the oceans.Which statement correctly describes a reaction of this system in response to an environmental change?

Enzymes of the acid-base catalysis type contain

Plot free energy versus the time course of an endergonic reaction, and do the same for an exergonic reaction.Include the activation energy on both plots.Label Ea and G on both graphs.

Refer to the graph below. The graph shows data collected using a purified enzyme to catalyze a reaction.Magnesium ion likely functions as a _______ in this reaction.

Heat, light, electricity, and motion are all examples of _______ energy.

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

Refer to the table below. Information about two reactions is provided.From this information, it can be stated that reaction _ is exergonic because its G° is _.

The enzymes catalase and malate dehydrogenase are both classified as oxidoreductases.Catalase has a heme group present at its catalytic site, whereas malate dehydrogenase has no bound cofactors or prosthetic groups and uses NAD⁺ as a coenzyme.What can you infer about these two enzymes?

Plot free energy versus the time course of an endergonic reaction, and do the same for an exergonic reaction.Include the activation energy on both plots.Label E_a and G on both graphs.