Question 1

In a biological system, you want to determine whether the conversion of A to B is at equilibrium.Which is a reasonable method to use to answer this question?

Accepted Answer

A)  Measure the concentrations of A and B and see if they change. 
B)  Measure the change in free energy at varying temperatures. 
C)  Add more A and see if B decreases. 
D)  Measure the concentrations of A and B and see if they are equal. 
E)  Add the competitive inhibitor C to see if the reaction stops. 
A)  Measure the concentrations of A and B and see if they change. 
B)  Measure the change in free energy at varying temperatures. 
C)  Add more A and see if B decreases. 
D)  Measure the concentrations of A and B and see if they are equal. 
E)  Add the competitive inhibitor C to see if the reaction stops.

Question 2

Refer to the figure below showing the change in free energy resulting from a chemical reaction.   Which statement about the reaction is true?

Accepted Answer

A)  It is an endergonic reaction. 
B)  The reactants have less energy than the products. 
C)  F1F1F1S1F1F1F10G is negative. 
D)  It is an example of a condensation reaction. 
E)  It is an anabolic reaction. 
A)  It is an endergonic reaction. 
B)  The reactants have less energy than the products. 
C)  F1F1F1S1F1F1F10G is negative. 
D)  It is an example of a condensation reaction. 
E)  It is an anabolic reaction.

Question 3

Which statement best describes the mechanism by which enzymes catalyze a reaction?

Accepted Answer

A)  Enzymes lower the energy barrier necessary to achieve the transition state of a reaction. 
B)  Enzymes lower the concentration of the products, thereby driving the reaction to favor product formation. 
C)  Enzymes lower the concentration of the substrates, thereby driving the equilibrium to favor product formation. 
D)  Enzymes absorb the change in enthalpy (F1F1F1S1F1F1F10H), permitting a reaction to proceed. 
E)  Enzymes are completely used up in the course of the reaction and therefore favor product formation. 
A)  Enzymes lower the energy barrier necessary to achieve the transition state of a reaction. 
B)  Enzymes lower the concentration of the products, thereby driving the reaction to favor product formation. 
C)  Enzymes lower the concentration of the substrates, thereby driving the equilibrium to favor product formation. 
D)  Enzymes absorb the change in enthalpy (F1F1F1S1F1F1F10H), permitting a reaction to proceed. 
E)  Enzymes are completely used up in the course of the reaction and therefore favor product formation.

Question 4

The enzyme threonine deaminase converts the amino acid threonine to 2-ketobutyrate.However, only l-threonine serves as a substrate.The enzyme does not recognize d-threonine as a substrate.Explain this.

Accepted Answer

Enzyme active sites are highly specific

Question 5

All of the following are examples of potential energy except

Accepted Answer

A)  chemical bonds. 
B)  concentration gradients. 
C)  electrical charge imbalance. 
D)  muscle contractions. 
E)  electrical potential difference. 
A)  chemical bonds. 
B)  concentration gradients. 
C)  electrical charge imbalance. 
D)  muscle contractions. 
E)  electrical potential difference.

Question 6

What is the result of the hydrolysis of ATP? Draw the products using the reactants' structures given in the figure below as a guide.

Accepted Answer

The hydrolysis of AT

Question 7

Refer to the table below.   The table shows data collected from three forms of the same enzyme-one normal form and two mutant forms.The data show that the _______ form has the greatest affinity for substrate.

Accepted Answer

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

Question 8

The F1F1F1S1F1F1F10G of ATP hydrolysis is negative, and the change in entropy is positive.The reaction, therefore,

Accepted Answer

A)  requires energy. 
B)  is endergonic. 
C)  is exergonic. 
D)  will not reach equilibrium. 
E)  decreases the disorder in the system. 
A)  requires energy. 
B)  is endergonic. 
C)  is exergonic. 
D)  will not reach equilibrium. 
E)  decreases the disorder in the system.

Question 9

In order to determine whether a reaction is at "saturation," you can add _______ and determine whether the reaction rate _______.

Accepted Answer

A)  ATP; increases 
B)  more substrate; increases 
C)  a competitive inhibitor; decreases 
D)  a downstream product; decreases 
E)  a noncompetitive inhibitor; decreases 
A)  ATP; increases 
B)  more substrate; increases 
C)  a competitive inhibitor; decreases 
D)  a downstream product; decreases 
E)  a noncompetitive inhibitor; decreases

Question 10

Amylase is a digestive enzyme secreted in human saliva that breaks down starch.Amylase functions well in the mouth but ceases to function in the stomach.Explain why.

Accepted Answer

The pH optimum of amylase is approximate

Question 11

Which term refers to the location on the enzyme where the substrates are bound?

Accepted Answer

A)  Inactive site 
B)  Allosteric site 
C)  Active site 
D)  Inhibition site 
E)  Helical site 
A)  Inactive site 
B)  Allosteric site 
C)  Active site 
D)  Inhibition site 
E)  Helical site

Question 12

Which statement about ATP is false?

Accepted Answer

A)  The synthesis of ATP is an endergonic reaction. 
B)  The hydrolysis of ATP to ADP and Pi is an exergonic reaction. 
C)  The phosphate bond energy of ATP cannot be harnessed for work. 
D)  ATP is a building block of RNA. 
E)  The phosphate bond energy of ATP may be transformed into light energy. 
A)  The synthesis of ATP is an endergonic reaction. 
B)  The hydrolysis of ATP to ADP and Pi is an exergonic reaction. 
C)  The phosphate bond energy of ATP cannot be harnessed for work. 
D)  ATP is a building block of RNA. 
E)  The phosphate bond energy of ATP may be transformed into light energy.

Question 13

Ascorbic acid, which is found in citrus fruits, acts as an inhibitor to catechol oxidase, the enzyme responsible for the browning reaction in fruits such as apples, peaches, and pears.One explanation for the inhibiting function of ascorbic acid could be its similarity, in terms of size and shape, to catechol, the substrate of the browning reaction.If this explanation is correct, then this inhibition is most likely an example of _______ inhibition.

Accepted Answer

A)  competitive 
B)  indirect 
C)  noncompetitive 
D)  allosteric 
E)  feedback 
A)  competitive 
B)  indirect 
C)  noncompetitive 
D)  allosteric 
E)  feedback

Question 14

An inhibitor that binds through covalent bonds to the active site of an enzyme is known as a(n) _______ inhibitor.

Accepted Answer

A)  irreversible 
B)  reversible 
C)  destructive 
D)  allosteric 
E)  competitive 
A)  irreversible 
B)  reversible 
C)  destructive 
D)  allosteric 
E)  competitive

Question 15

The sum total of all chemical reactions in a living organism is called its

Accepted Answer

A)  energetics. 
B)  activity. 
C)  digestive power. 
D)  entropy. 
E)  metabolism. 
A)  energetics. 
B)  activity. 
C)  digestive power. 
D)  entropy. 
E)  metabolism.

Question 16

Refer to the figure below.   The figure illustrates how the amino acid isoleucine is biosynthesized in cells from the amino acid threonine.The figure also illustrates how this metabolic pathway is regulated through a process called _______.

Accepted Answer

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

Question 17

The ΔG of a reaction is dependent on all of the following except

Accepted Answer

A)  the free energy of the products. 
B)  the free energy of the reactants. 
C)  the change in enthalpy. 
D)  the change in entropy. 
E)  the change in the activation energy. 
A)  the free energy of the products. 
B)  the free energy of the reactants. 
C)  the change in enthalpy. 
D)  the change in entropy. 
E)  the change in the activation energy.

Question 18

Which enzymes' catalytic activity is predicted to be most sensitive to changes in pH?

Accepted Answer

A)  Enzymes with nonpolar side chains at the active site 
B)  Enzymes with amino (-NH2) or carboxy (-COOH) side chains at the active site 
C)  Enzymes with metal ions bound to nonpolar side chains at the active site 
D)  Enzymes with structurally smaller side chains (e.g., -H) at the active site 
E)  Enzymes with structurally rigid side chains (e.g., proline residues) at the active site 
A)  Enzymes with nonpolar side chains at the active site 
B)  Enzymes with amino (-NH2) or carboxy (-COOH) side chains at the active site 
C)  Enzymes with metal ions bound to nonpolar side chains at the active site 
D)  Enzymes with structurally smaller side chains (e.g., -H) at the active site 
E)  Enzymes with structurally rigid side chains (e.g., proline residues) at the active site

Question 19

What would happen to the value of F1F1F1S1F1F1F10G for the reaction in which phosphoenolpyruvate is converted to pyruvate (F1F1F1S1F1F1F10G = -23 kJ/mol) when it reaches equilibrium?

Accepted Answer

A)  F1F1F1S1F1F1F10G would equal -23 kJ/mol. 
B)  F1F1F1S1F1F1F10G would become more negative. 
C)  F1F1F1S1F1F1F10G would become more positive. 
D)  F1F1F1S1F1F1F10G would depend on the activity of its enzyme pyruvate kinase. 
E)  F1F1F1S1F1F1F10G would equal 0. 
A)  F1F1F1S1F1F1F10G would equal -23 kJ/mol. 
B)  F1F1F1S1F1F1F10G would become more negative. 
C)  F1F1F1S1F1F1F10G would become more positive. 
D)  F1F1F1S1F1F1F10G would depend on the activity of its enzyme pyruvate kinase. 
E)  F1F1F1S1F1F1F10G would equal 0.

Question 20

Construct a diagram to illustrate how an enzyme can be regulated in a reversible fashion via phosphorylation.

Accepted Answer

The answer of Construct a diagram to illustrate how an...

Exam 8: Energy, Enzymes, and Metabolism

In a biological system, you want to determine whether the conversion of A to B is at equilibrium.Which is a reasonable method to use to answer this question?

Refer to the figure below showing the change in free energy resulting from a chemical reaction. Which statement about the reaction is true?

Which statement best describes the mechanism by which enzymes catalyze a reaction?

The enzyme threonine deaminase converts the amino acid threonine to 2-ketobutyrate.However, only l-threonine serves as a substrate.The enzyme does not recognize d-threonine as a substrate.Explain this.

All of the following are examples of potential energy except

What is the result of the hydrolysis of ATP? Draw the products using the reactants' structures given in the figure below as a guide.

Refer to the table below. The table shows data collected from three forms of the same enzyme-one normal form and two mutant forms.The data show that the _______ form has the greatest affinity for substrate.

The G of ATP hydrolysis is negative, and the change in entropy is positive.The reaction, therefore,

In order to determine whether a reaction is at "saturation," you can add _______ and determine whether the reaction rate _______.

Amylase is a digestive enzyme secreted in human saliva that breaks down starch.Amylase functions well in the mouth but ceases to function in the stomach.Explain why.

Which term refers to the location on the enzyme where the substrates are bound?

Which statement about ATP is false?

An inhibitor that binds through covalent bonds to the active site of an enzyme is known as a(n) _______ inhibitor.

The sum total of all chemical reactions in a living organism is called its

Refer to the figure below. The figure illustrates how the amino acid isoleucine is biosynthesized in cells from the amino acid threonine.The figure also illustrates how this metabolic pathway is regulated through a process called _______.

The ΔG of a reaction is dependent on all of the following except

Which enzymes' catalytic activity is predicted to be most sensitive to changes in pH?

What would happen to the value of G for the reaction in which phosphoenolpyruvate is converted to pyruvate (G = -23 kJ/mol) when it reaches equilibrium?

Construct a diagram to illustrate how an enzyme can be regulated in a reversible fashion via phosphorylation.

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

In order to determine whether a reaction is at "saturation," you can add _ and determine whether the reaction rate _.