Question 1

A reaction,where a molecule is altered through a series of defined steps,resulting in a particular product is known as a(n)

Accepted Answer

A) metabolic pathway. 
B) catabolic pathway. 
C) reversible reaction. 
D) degradation pathway. 
E) anabolic pathway. 
A) metabolic pathway. 
B) catabolic pathway. 
C) reversible reaction. 
D) degradation pathway. 
E) anabolic pathway.

Question 2

Use the following information to answer the questions below.
A patient comes into the emergency room having accidentally ingested methanol (a component in anti-freeze).The products of methanol degradation are toxic,and can lead to blindness,neurological issues,or death.However,if methanol degradation can be slowed down,the toxic by-products do not have a chance to accumulate.ADH has a higher affinity to ethanol,where it functions to oxidize ethanol into acetaldehyde with the end product of the pathway being acetic acid (vinegar).
-This treatment functions under the principle of

Accepted Answer

A) competitive inhibition. 
B) non-competitive inhibition. 
C) feedback inhibition. 
D) allosteric inhibition. 
E) there is no treatment. 
A) competitive inhibition. 
B) non-competitive inhibition. 
C) feedback inhibition. 
D) allosteric inhibition. 
E) there is no treatment.

Question 3

The following questions are based on the reaction A + B ↔ C + D shown in the figure below.
  
-Assume that the reaction in the figure above has a ΔG of -5.6 kcal/mol.Which of the following would be true?

Accepted Answer

A) The reaction could be coupled to power an endergonic reaction with a ΔG of +6.2 kcal/mol. 
B) The reaction could be coupled to power an exergonic reaction with a ΔG of +8.8 kcal/mol. 
C) The reaction would result in a decrease in entropy (S)and an increase in the total energy content (H)of the system. 
D) The reaction would result in an increase in entropy (S)and a decrease in the total energy content (H)of the system. 
E) The reaction would result in products (C + 
D) . 
A) The reaction could be coupled to power an endergonic reaction with a ΔG of +6.2 kcal/mol. 
B) The reaction could be coupled to power an exergonic reaction with a ΔG of +8.8 kcal/mol. 
C) The reaction would result in a decrease in entropy (S)and an increase in the total energy content (H)of the system. 
D) The reaction would result in an increase in entropy (S)and a decrease in the total energy content (H)of the system. 
E) The reaction would result in products (C + 
D) .

Question 4

Allosteric enzyme regulation is usually associated with

Accepted Answer

A) lack of cooperativity. 
B) feedback inhibition. 
C) activating activity. 
D) an enzyme with more than one subunit. 
E) the need for cofactors. 
A) lack of cooperativity. 
B) feedback inhibition. 
C) activating activity. 
D) an enzyme with more than one subunit. 
E) the need for cofactors.

Question 5

When 10 000 molecules of ATP are hydrolyzed to ADP and℗ ᵢ in a test tube,about twice as much heat is liberated as when a cell hydrolyzes the same amount of ATP.Which of the following is the best explanation for this observation?

Accepted Answer

A) Living systems harness the energy released to perform work. 
B) Cells are less efficient at heat production than nonliving systems. 
C) The hydrolysis of ATP in a cell produces different chemical products than does the reaction in a test tube. 
D) The reaction in cells must be catalyzed by enzymes, but the reaction in a test tube does not need enzymes. 
E) Reactant and product concentrations in the test tube are different from those in the cell. 
A) Living systems harness the energy released to perform work. 
B) Cells are less efficient at heat production than nonliving systems. 
C) The hydrolysis of ATP in a cell produces different chemical products than does the reaction in a test tube. 
D) The reaction in cells must be catalyzed by enzymes, but the reaction in a test tube does not need enzymes. 
E) Reactant and product concentrations in the test tube are different from those in the cell.

Question 6

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

Accepted Answer

A) the muscle contractions of a person mowing grass 
B) water rushing over Niagara Falls 
C) light flashes emitted by a firefly 
D) a molecule of glucose 
E) the flight of an insect foraging for food 
A) the muscle contractions of a person mowing grass 
B) water rushing over Niagara Falls 
C) light flashes emitted by a firefly 
D) a molecule of glucose 
E) the flight of an insect foraging for food

Question 7

Use the following information to answer the questions below.
A series of enzymes catalyze the reaction 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.
-What is substance X?

Accepted Answer

A) a coenzyme 
B) an allosteric inhibitor 
C) a substrate 
D) an intermediate 
E) the product 
A) a coenzyme 
B) an allosteric inhibitor 
C) a substrate 
D) an intermediate 
E) the product

Question 8

Use the following information to answer the questions below.
   
Activity of various enzymes at various temperatures (a)and at various pH (b).
-Which curve(s)on the graphs may represent the temperature and pH profiles of an enzyme taken from a bacterium that lives in a mildly alkaline hot springs at temperatures of 70°C or higher?

Accepted Answer

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

Question 9

The following questions are based on the reaction A + B ↔ C + D shown in the figure below.
  
-Which of the following represents the activation energy required for the enzyme-catalyzed reaction in the figure above?

Accepted Answer

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

Question 10

How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?

Accepted Answer

A) by binding at the active site of the enzyme 
B) by changing the shape of the enzyme's active site 
C) by changing the free energy change of the reaction 
D) by acting as a coenzyme for the reaction 
E) by decreasing the activation energy of the reaction 
A) by binding at the active site of the enzyme 
B) by changing the shape of the enzyme's active site 
C) by changing the free energy change of the reaction 
D) by acting as a coenzyme for the reaction 
E) by decreasing the activation energy of the reaction

Question 11

The following questions are based on the reaction A + B ↔ C + D shown in the figure below.
  
-Which of the following represents the difference between the free-energy content of the reaction and the free-energy content of the products in the figure above?

Accepted Answer

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

Question 12

Protein kinases are enzymes that catalyze phosphorylation of target proteins at specific sites,whereas protein phosphatases catalyze removal of phosphate(s)from phosphorylated proteins.Phosphorylation and dephosphorylation can function as an on-off switch for a protein's activity,most likely through

Accepted Answer

A) the change in a protein's charge leading to a conformational change. 
B) the change in a protein's charge leading to cleavage. 
C) a change in the optimal pH at which a reaction will occur. 
D) a change in the optimal temperature at which a reaction will occur. 
E) the excision of one or more peptides. 
A) the change in a protein's charge leading to a conformational change. 
B) the change in a protein's charge leading to cleavage. 
C) a change in the optimal pH at which a reaction will occur. 
D) a change in the optimal temperature at which a reaction will occur. 
E) the excision of one or more peptides.

Question 13

Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's

Accepted Answer

A) entropy. 
B) activation energy. 
C) endothermic level. 
D) equilibrium point. 
E) free-energy content. 
A) entropy. 
B) activation energy. 
C) endothermic level. 
D) equilibrium point. 
E) free-energy content.

Question 14

When glucose monomers are joined together by glycosidic linkages to form a cellulose polymer,the changes in free energy,total energy,and entropy are as follows

Accepted Answer

A) +ΔG, +ΔH, +ΔS. 
B) +ΔG, +ΔH, -ΔS. 
C) +ΔG, -ΔH, -ΔS. 
D) -ΔG, +ΔH, +ΔS. 
E) -ΔG, -ΔH, -ΔS. 
A) +ΔG, +ΔH, +ΔS. 
B) +ΔG, +ΔH, -ΔS. 
C) +ΔG, -ΔH, -ΔS. 
D) -ΔG, +ΔH, +ΔS. 
E) -ΔG, -ΔH, -ΔS.

Question 15

According to the induced-fit hypothesis of enzyme catalysis,which of the following is correct?

Accepted Answer

A) The binding of the substrate depends on the shape of the active site. 
B) Some enzymes change their structure when activators bind to the enzyme. 
C) A competitive inhibitor can outcompete the substrate for the active site. 
D) The binding of the substrate changes the shape of the enzyme's active site. 
E) The active site creates a microenvironment ideal for the reaction. 
A) The binding of the substrate depends on the shape of the active site. 
B) Some enzymes change their structure when activators bind to the enzyme. 
C) A competitive inhibitor can outcompete the substrate for the active site. 
D) The binding of the substrate changes the shape of the enzyme's active site. 
E) The active site creates a microenvironment ideal for the reaction.

Question 16

An organic molecule is required for the catalytic activity of an enzyme.What is the most specific name below for this molecule?

Accepted Answer

A) cofactor 
B) coenzyme 
C) allosteric activator 
D) cooperative activator 
E) substrate 
A) cofactor 
B) coenzyme 
C) allosteric activator 
D) cooperative activator 
E) substrate

Question 17

Use the following figure to answer the questions below.
  
-Which of the following is the most correct interpretation of the figure?

Accepted Answer

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

Question 18

A chemical reaction that has a positive ΔG is correctly described as

Accepted Answer

A) endergonic. 
B) endothermic. 
C) enthalpic. 
D) spontaneous. 
E) exothermic. 
A) endergonic. 
B) endothermic. 
C) enthalpic. 
D) spontaneous. 
E) exothermic.

Question 19

Mutations that result in single amino acid substitutions in an enzyme

Accepted Answer

A) may have no effect on the activity or properties of the enzyme. 
B) will almost always destroy the activity of the enzyme. 
C) will often cause a change in the substrate specificity of the enzyme. 
D) may change the ∆G of the reaction. 
E) may, in rare cases, cause the enzyme to run reactions in reverse. 
A) may have no effect on the activity or properties of the enzyme. 
B) will almost always destroy the activity of the enzyme. 
C) will often cause a change in the substrate specificity of the enzyme. 
D) may change the ∆G of the reaction. 
E) may, in rare cases, cause the enzyme to run reactions in reverse.

Question 20

Use the following information to answer the questions below.
A patient comes into the emergency room having accidentally ingested methanol (a component in anti-freeze).The products of methanol degradation are toxic,and can lead to blindness,neurological issues,or death.However,if methanol degradation can be slowed down,the toxic by-products do not have a chance to accumulate.ADH has a higher affinity to ethanol,where it functions to oxidize ethanol into acetaldehyde with the end product of the pathway being acetic acid (vinegar).
-Knowing what you know about enzyme function,what would be your suggested course of treatment?

Accepted Answer

A) Give plenty of fluids and monitor the patient. 
B) Give the patient acetic acid. 
C) Give the patient high levels of ethanol and carefully monitor. 
D) Keep the patient warm and rested and let it take its course. 
E) Induce a controlled fever. 
A) Give plenty of fluids and monitor the patient. 
B) Give the patient acetic acid. 
C) Give the patient high levels of ethanol and carefully monitor. 
D) Keep the patient warm and rested and let it take its course. 
E) Induce a controlled fever.

Exam 8: An Introduction to Metabolism

A reaction,where a molecule is altered through a series of defined steps,resulting in a particular product is known as a(n)

The following questions are based on the reaction A + B ↔ C + D shown in the figure below. -Assume that the reaction in the figure above has a ΔG of -5.6 kcal/mol.Which of the following would be true?

Allosteric enzyme regulation is usually associated with

When 10 000 molecules of ATP are hydrolyzed to ADP and℗ ᵢ in a test tube,about twice as much heat is liberated as when a cell hydrolyzes the same amount of ATP.Which of the following is the best explanation for this observation?

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

Use the following information to answer the questions below. A series of enzymes catalyze the reaction 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. -What is substance X?

The following questions are based on the reaction A + B ↔ C + D shown in the figure below. -Which of the following represents the activation energy required for the enzyme-catalyzed reaction in the figure above?

How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?

The following questions are based on the reaction A + B ↔ C + D shown in the figure below. -Which of the following represents the difference between the free-energy content of the reaction and the free-energy content of the products in the figure above?

Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reaction's

When glucose monomers are joined together by glycosidic linkages to form a cellulose polymer,the changes in free energy,total energy,and entropy are as follows

According to the induced-fit hypothesis of enzyme catalysis,which of the following is correct?

An organic molecule is required for the catalytic activity of an enzyme.What is the most specific name below for this molecule?

Use the following figure to answer the questions below. -Which of the following is the most correct interpretation of the figure?

A chemical reaction that has a positive ΔG is correctly described as

Mutations that result in single amino acid substitutions in an enzyme

Introduction: Evolution and Themes of Biology

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

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

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 Signalling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behaviour

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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