Question 1

Why do reversible reactions in a cell rarely reach equilibrium?

Accepted Answer

A) because the products are generally reactants in other reactions and are thus immediately used 
B) because most reactions in a cell are not reversible, thus allowing the cell to devote additional resources to regulating the few reversible reactions that do occur 
C) because cells have no way of measuring the relative ratios of reactants and products 
D) because a cell at equilibrium is dead 
A) because the products are generally reactants in other reactions and are thus immediately used 
B) because most reactions in a cell are not reversible, thus allowing the cell to devote additional resources to regulating the few reversible reactions that do occur 
C) because cells have no way of measuring the relative ratios of reactants and products 
D) because a cell at equilibrium is dead

Question 2

Match each definition with the corresponding term.
-phosphorylation

Accepted Answer

A) primary coupling agent in cellular reactions 
B) addition of a phosphate group to a target molecule 
C) product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity 
D) linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion 
E) series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
F)substance that facilitates a chemical reaction without itself being consumed by the reaction
G)energy needed to start a reaction, be it endergonic or exergonic
H)portion of the enzyme that binds to a reactant or reactants
I)state in which the rate of the forward reaction equals the rate of the reverse reaction
J)intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
K)reactant molecule that binds to an enzyme 
A) primary coupling agent in cellular reactions 
B) addition of a phosphate group to a target molecule 
C) product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity 
D) linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion 
E) series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
F)substance that facilitates a chemical reaction without itself being consumed by the reaction
G)energy needed to start a reaction, be it endergonic or exergonic
H)portion of the enzyme that binds to a reactant or reactants
I)state in which the rate of the forward reaction equals the rate of the reverse reaction
J)intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
K)reactant molecule that binds to an enzyme

Question 3

Activation energy is not required for nonspontaneous reactions.

Accepted Answer

A) True 
 B)False

Question 4

What does it mean when an enzyme has an allosteric activator?

Accepted Answer

A) The product of the enzyme, or another downstream product, will bind to the enzyme at a site other than the active site and inhibit enzyme activity. 
B) The product of the enzyme, or another downstream product, will bind to the enzyme at the active site and stimulate enzyme activity. 
C) The product of the enzyme, or another downstream product, will bind to the enzyme at a site other than the active site and stimulate enzyme activity. 
D) The product of the enzyme, or another downstream product, will bind to the enzyme at the active site and inhibit enzyme activity. 
A) The product of the enzyme, or another downstream product, will bind to the enzyme at a site other than the active site and inhibit enzyme activity. 
B) The product of the enzyme, or another downstream product, will bind to the enzyme at the active site and stimulate enzyme activity. 
C) The product of the enzyme, or another downstream product, will bind to the enzyme at a site other than the active site and stimulate enzyme activity. 
D) The product of the enzyme, or another downstream product, will bind to the enzyme at the active site and inhibit enzyme activity.

Question 5

Match each definition with the corresponding term.
-ATP

Accepted Answer

A) primary coupling agent in cellular reactions 
B) addition of a phosphate group to a target molecule 
C) product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity 
D) linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion 
E) series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
F)substance that facilitates a chemical reaction without itself being consumed by the reaction
G)energy needed to start a reaction, be it endergonic or exergonic
H)portion of the enzyme that binds to a reactant or reactants
I)state in which the rate of the forward reaction equals the rate of the reverse reaction
J)intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
K)reactant molecule that binds to an enzyme 
A) primary coupling agent in cellular reactions 
B) addition of a phosphate group to a target molecule 
C) product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity 
D) linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion 
E) series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
F)substance that facilitates a chemical reaction without itself being consumed by the reaction
G)energy needed to start a reaction, be it endergonic or exergonic
H)portion of the enzyme that binds to a reactant or reactants
I)state in which the rate of the forward reaction equals the rate of the reverse reaction
J)intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
K)reactant molecule that binds to an enzyme

Question 6

Enzymes do not change the ?G of a reaction.

Accepted Answer

A) True 
 B)False

Question 7

Which phrase best describes how endergonic reactions are coupled within a cell?

Accepted Answer

A) Endergonic reactions are coupled to endergonic reactions to produce ATP. 
B) Endergonic reactions are coupled to exergonic reactions to produce ATP. 
C) Endergonic reactions are coupled to exergonic reactions to produce AMP. 
D) Endergonic reactions are coupled to endergonic reactions to produce AMP. 
A) Endergonic reactions are coupled to endergonic reactions to produce ATP. 
B) Endergonic reactions are coupled to exergonic reactions to produce ATP. 
C) Endergonic reactions are coupled to exergonic reactions to produce AMP. 
D) Endergonic reactions are coupled to endergonic reactions to produce AMP.

Question 8

Enzymes work with at least three mechanisms. Which of the following is NOT a mechanism by which enzymes function?

Accepted Answer

A) by putting reactants in close proximity to each other 
B) by altering the free energy (   G) of the reaction 
C) by orienting the reactants so they are positioned to favour the transition state 
D) by altering the immediate environment of the reactants to promote reactant interactions 
A) by putting reactants in close proximity to each other 
B) by altering the free energy (   G) of the reaction 
C) by orienting the reactants so they are positioned to favour the transition state 
D) by altering the immediate environment of the reactants to promote reactant interactions

Question 9

Which sentence best describes the process of noncompetitive feedback inhibition?

Accepted Answer

A) The inhibitor binds to the active site and directly blocks the active site of the enzyme. 
B) The products of the reaction at the end of the pathway bind to a site other than the active site of an enzyme at or near the beginning of the pathway, and block enzyme activity indirectly. 
C) The products of the reaction at the end of the pathway block the active site of the enzyme, inhibiting it directly. 
D) The substrate and cofactors compete for the active site of an enzyme and block enzyme activity directly. 
A) The inhibitor binds to the active site and directly blocks the active site of the enzyme. 
B) The products of the reaction at the end of the pathway bind to a site other than the active site of an enzyme at or near the beginning of the pathway, and block enzyme activity indirectly. 
C) The products of the reaction at the end of the pathway block the active site of the enzyme, inhibiting it directly. 
D) The substrate and cofactors compete for the active site of an enzyme and block enzyme activity directly.

Question 10

Which of the following is a correct pair based on their shared characteristics?

Accepted Answer

A) the universe and a closed system 
B) the universe and an open system 
C) an ocean and an open system 
D) an ocean and a closed system 
A) the universe and a closed system 
B) the universe and an open system 
C) an ocean and an open system 
D) an ocean and a closed system

Question 11

When ATP is split into ADP and Pi, what happens to the energy that gets released?

Accepted Answer

A) The energy is transferred to the target molecule via the transfer of Pi. 
B) The energy is directly transferred to the target molecule by an unknown mechanism. 
C) The two remaining phosphates acquire the energy that was present in the linkage of three phosphates. 
D) The energy dissipates in the form of heat. 
A) The energy is transferred to the target molecule via the transfer of Pi. 
B) The energy is directly transferred to the target molecule by an unknown mechanism. 
C) The two remaining phosphates acquire the energy that was present in the linkage of three phosphates. 
D) The energy dissipates in the form of heat.

Question 12

Match each definition with the corresponding term.
-coupled reaction

Accepted Answer

A) primary coupling agent in cellular reactions 
B) addition of a phosphate group to a target molecule 
C) product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity 
D) linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion 
E) series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
F)substance that facilitates a chemical reaction without itself being consumed by the reaction
G)energy needed to start a reaction, be it endergonic or exergonic
H)portion of the enzyme that binds to a reactant or reactants
I)state in which the rate of the forward reaction equals the rate of the reverse reaction
J)intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
K)reactant molecule that binds to an enzyme 
A) primary coupling agent in cellular reactions 
B) addition of a phosphate group to a target molecule 
C) product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity 
D) linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion 
E) series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
F)substance that facilitates a chemical reaction without itself being consumed by the reaction
G)energy needed to start a reaction, be it endergonic or exergonic
H)portion of the enzyme that binds to a reactant or reactants
I)state in which the rate of the forward reaction equals the rate of the reverse reaction
J)intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
K)reactant molecule that binds to an enzyme

Question 13

-Which letter on the graph indicates the activation energy when an enzyme is present?

Accepted Answer

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

Question 14

At equilibrium, the concentration of the reactants equals the concentration of the products.

Accepted Answer

A) True 
 B)False

Question 15

For each situation, choose the most appropriate term.
-folding laundry

Accepted Answer

A) endergonic 
B) exergonic 
C) equilibrium 
A) endergonic 
B) exergonic 
C) equilibrium

Question 16

Match each definition with the corresponding term.
-allosteric regulation

Accepted Answer

A) primary coupling agent in cellular reactions 
B) addition of a phosphate group to a target molecule 
C) product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity 
D) linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion 
E) series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
F)substance that facilitates a chemical reaction without itself being consumed by the reaction
G)energy needed to start a reaction, be it endergonic or exergonic
H)portion of the enzyme that binds to a reactant or reactants
I)state in which the rate of the forward reaction equals the rate of the reverse reaction
J)intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
K)reactant molecule that binds to an enzyme 
A) primary coupling agent in cellular reactions 
B) addition of a phosphate group to a target molecule 
C) product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity 
D) linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion 
E) series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
F)substance that facilitates a chemical reaction without itself being consumed by the reaction
G)energy needed to start a reaction, be it endergonic or exergonic
H)portion of the enzyme that binds to a reactant or reactants
I)state in which the rate of the forward reaction equals the rate of the reverse reaction
J)intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
K)reactant molecule that binds to an enzyme

Question 17

Which of the following best describes an ocean as an open system?

Accepted Answer

A) It does not exchange matter with its surroundings. 
B) It absorbs but not releases energy. 
C) It absorbs and releases energy. 
D) It exchanges energy but not matter with its surroundings. 
A) It does not exchange matter with its surroundings. 
B) It absorbs but not releases energy. 
C) It absorbs and releases energy. 
D) It exchanges energy but not matter with its surroundings.

Question 18

Which of the following best describes why thinking of entropy as disorder is problematic?

Accepted Answer

A) This idea can be applied scientifically in a precise way, and entropy is not governed by order. 
B) This idea can be applied scientifically in a precise way, and entropy is governed by order. 
C) This idea cannot be applied scientifically in a precise way, and entropy is governed by order. 
D) This idea cannot be applied scientifically in a precise way, and entropy is not governed by order. 
A) This idea can be applied scientifically in a precise way, and entropy is not governed by order. 
B) This idea can be applied scientifically in a precise way, and entropy is governed by order. 
C) This idea cannot be applied scientifically in a precise way, and entropy is governed by order. 
D) This idea cannot be applied scientifically in a precise way, and entropy is not governed by order.

Question 19

Which of the following best explains why machines can never be 100% efficient?

Accepted Answer

A) the tendency of energy not to spread out 
B) the tendency of energy to spread out 
C) the tendency of energy to be kept 
D) the tendency of energy to be lost 
A) the tendency of energy not to spread out 
B) the tendency of energy to spread out 
C) the tendency of energy to be kept 
D) the tendency of energy to be lost

Question 20

For each situation, choose the most appropriate term.
-the rate of synthesis equals the rate of degradation

Accepted Answer

A) endergonic 
B) exergonic 
C) equilibrium 
A) endergonic 
B) exergonic 
C) equilibrium

Exam 4: Energy and Enzymes

Why do reversible reactions in a cell rarely reach equilibrium?

Match each definition with the corresponding term. -phosphorylation

Activation energy is not required for nonspontaneous reactions.

What does it mean when an enzyme has an allosteric activator?

Match each definition with the corresponding term. -ATP

Enzymes do not change the ?G of a reaction.

Which phrase best describes how endergonic reactions are coupled within a cell?

Enzymes work with at least three mechanisms. Which of the following is NOT a mechanism by which enzymes function?

Which sentence best describes the process of noncompetitive feedback inhibition?

Which of the following is a correct pair based on their shared characteristics?

When ATP is split into ADP and Pi, what happens to the energy that gets released?

Match each definition with the corresponding term. -coupled reaction

-Which letter on the graph indicates the activation energy when an enzyme is present?

At equilibrium, the concentration of the reactants equals the concentration of the products.

For each situation, choose the most appropriate term. -folding laundry

Match each definition with the corresponding term. -allosteric regulation

Which of the following best describes an ocean as an open system?

Which of the following best describes why thinking of entropy as disorder is problematic?

Which of the following best explains why machines can never be 100% efficient?

For each situation, choose the most appropriate term. -the rate of synthesis equals the rate of degradation

Light and Life

The Cell: an Overview

Defining Life and Its Origins

Cell Membranes and Signalling

Cellular Respiration

Photosynthesis

Cell Cycles

Genetic Recombination

Mendel, Genes, and Inheritance

Genes, Chromosomes, and Human Genetics

Dna Structure, Replication, and Organization

Gene Structure and Expression

Control of Gene Expression

Dna Technologies

Genomes and Proteomes

Evolution: the Development of the Theory

Microevolution: Changes Within Populations

Species and Macroevolution

Understanding the History of Life on Earth

Humans and Evolution

Bacteria and Archaea

Viruses, Viroids, and Prions: Infectious Biological Particles

Protists

Fungi

Plants

Diversity of Animals 1: Sponges, Radiata, Platyhelminthes, and Protostomes

Diversity of Animals 2: Deuterostomes: Vertebrates and Their Closest Relatives

Population Ecology

Population Interactions and Community Ecology

Ecosystems

Conservation of Biodiversity

Putting Selection to Work

Organization of the Plant Body

Transport in Plants

Reproduction and Development in Flowering Plants

Plant Nutrition

Plant Signals and Responses to the Environment

Introduction to Animal Organization and Physiology

Transport in Animals: the Circulatory System

Reproduction in Animals

Animal Development

Control of Animal Processes: Neural Control

Control of Animal Processes: Neural Control

Control of Animal Processes: Neural Integration

Muscles, Skeletons, and Body Movements

Animal Behaviour

Animal Nutrition

Gas Exchange: the Respiratory System

Regulating the Internal Environment

Defences Against Disease

Conservation and Evolutionary Physiology

Filters

When ATP is split into ADP and P_i, what happens to the energy that gets released?