Question 1

Which of the following is true of metabolism in its entirety in all organisms?

Accepted Answer

A)  Metabolism depends on a constant supply of energy from food. 
B)  Metabolism depends on an organism's adequate hydration. 
C)  Metabolism uses all of an organism's resources. 
D)  Metabolism consists of all the energy transformation reactions in an organism. 
E)  Metabolism manages the increase of entropy in an organism. 
A)  Metabolism depends on a constant supply of energy from food. 
B)  Metabolism depends on an organism's adequate hydration. 
C)  Metabolism uses all of an organism's resources. 
D)  Metabolism consists of all the energy transformation reactions in an organism. 
E)  Metabolism manages the increase of entropy in an organism.

Question 2

A system at chemical equilibrium

Accepted Answer

A)  consumes energy at a steady rate. 
B)  releases energy at a steady rate. 
C)  consumes or releases energy, depending on whether it is exergonic or endergonic. 
D)  has zero kinetic energy. 
E)  can do no work. 
A)  consumes energy at a steady rate. 
B)  releases energy at a steady rate. 
C)  consumes or releases energy, depending on whether it is exergonic or endergonic. 
D)  has zero kinetic energy. 
E)  can do no work.

Question 3

Biological evolution of life on Earth, from simple prokaryote-like cells to large, multicellar eukaryotic organisms,

Accepted Answer

A)  has occurred in accordance with the laws of thermodynamics. 
B)  has caused an increase in the entropy of the planet. 
C)  has been made possible by expending Earth's energy resources. 
D)  has occurred in accordance with the laws of thermodynamics, by expending Earth's energy resources and causing an increase in the entropy of the planet. 
E)  violates the laws of thermodynamics because Earth is a closed system. 
A)  has occurred in accordance with the laws of thermodynamics. 
B)  has caused an increase in the entropy of the planet. 
C)  has been made possible by expending Earth's energy resources. 
D)  has occurred in accordance with the laws of thermodynamics, by expending Earth's energy resources and causing an increase in the entropy of the planet. 
E)  violates the laws of thermodynamics because Earth is a closed system.

Question 4

The following questions are from the end-of-chapter "Test Your Understanding" section in Chapter 8 of the textbook.
-Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as ________ is to ________.

Accepted Answer

A)  exergonic; spontaneous 
B)  exergonic; endergonic 
C)  free energy; entropy 
D)  work; energy 
E)  entropy; enthalpy 
A)  exergonic; spontaneous 
B)  exergonic; endergonic 
C)  free energy; entropy 
D)  work; energy 
E)  entropy; enthalpy

Question 5

Which of the following statements is true about enzyme-catalyzed reactions?

Accepted Answer

A)  The reaction is faster than the same reaction in the absence of the enzyme. 
B)  The free energy change of the reaction is opposite from the reaction that occurs in the absence of the enzyme. 
C)  The reaction always goes in the direction toward chemical equilibrium. 
D)  Enzyme-catalyzed reactions require energy to activate the enzyme. 
E)  Enzyme-catalyzed reactions release more free energy than noncatalyzed reactions. 
A)  The reaction is faster than the same reaction in the absence of the enzyme. 
B)  The free energy change of the reaction is opposite from the reaction that occurs in the absence of the enzyme. 
C)  The reaction always goes in the direction toward chemical equilibrium. 
D)  Enzyme-catalyzed reactions require energy to activate the enzyme. 
E)  Enzyme-catalyzed reactions release more free energy than noncatalyzed reactions.

Question 6

What is the difference (if any)between the structure of ATP and the structure of the precursor of the A nucleotide in RNA?

Accepted Answer

A)  The sugar molecule is different. 
B)  The nitrogen-containing base is different. 
C)  The number of phosphates is three instead of one. 
D)  The number of phosphates is three instead of two. 
E)  There is no difference. 
A)  The sugar molecule is different. 
B)  The nitrogen-containing base is different. 
C)  The number of phosphates is three instead of one. 
D)  The number of phosphates is three instead of two. 
E)  There is no difference.

Question 7

The following questions are from the end-of-chapter "Test Your Understanding" section in Chapter 8 of the textbook.
-Some bacteria are metabolically active in hot springs because

Accepted Answer

A)  they are able to maintain a lower internal temperature. 
B)  high temperatures make catalysis unnecessary. 
C)  their enzymes have high optimal temperatures. 
D)  their enzymes are completely insensitive to temperature. 
E)  they use molecules other than proteins or RNAs as their main catalysts. 
A)  they are able to maintain a lower internal temperature. 
B)  high temperatures make catalysis unnecessary. 
C)  their enzymes have high optimal temperatures. 
D)  their enzymes are completely insensitive to temperature. 
E)  they use molecules other than proteins or RNAs as their main catalysts.

Question 8

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 9

Rate of an enzyme-catalyzed reaction as a function of varying reactant
concentration, with the concentration of enzyme constant.
-For the enzyme-catalyzed reaction shown in the figure, which of these treatments will cause the greatest increase in the rate of the reaction, if the initial reactant concentration is 1.0 micromolar?

Accepted Answer

A)  doubling the activation energy needed 
B)  cooling the reaction by 10°C 
C)  doubling the concentration of the reactants to 2.0 micromolar 
D)  doubling the enzyme concentration 
E)  increasing the concentration of reactants to 10.0 micromolar, while reducing the concentration of enzyme by 1/2 
A)  doubling the activation energy needed 
B)  cooling the reaction by 10°C 
C)  doubling the concentration of the reactants to 2.0 micromolar 
D)  doubling the enzyme concentration 
E)  increasing the concentration of reactants to 10.0 micromolar, while reducing the concentration of enzyme by 1/2

Question 10

For living organisms, which of the following is an important consequence of the first law of thermodynamics?

Accepted Answer

A)  The energy content of an organism is constant. 
B)  The organism ultimately must obtain all of the necessary energy for life from its environment. 
C)  The entropy of an organism decreases with time as the organism grows in complexity. 
D)  Organisms grow by converting energy into organic matter. 
E)  Life does not obey the first law of thermodynamics. 
A)  The energy content of an organism is constant. 
B)  The organism ultimately must obtain all of the necessary energy for life from its environment. 
C)  The entropy of an organism decreases with time as the organism grows in complexity. 
D)  Organisms grow by converting energy into organic matter. 
E)  Life does not obey the first law of thermodynamics.

Question 11

Mutations that result in single amino acid substitutions in an enzyme

Accepted Answer

A)  can 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 affect the physicochemical properties of the enzyme such as its optimal temperature and pH. 
E)  may, in rare cases, cause the enzyme to run reactions in reverse. 
A)  can 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 affect the physicochemical properties of the enzyme such as its optimal temperature and pH. 
E)  may, in rare cases, cause the enzyme to run reactions in reverse.

Question 12

Why is ATP an important molecule in metabolism?

Accepted Answer

A)  Its hydrolysis provides an input of free energy for exergonic reactions. 
B)  It provides energy coupling between exergonic and endergonic reactions. 
C)  Its terminal phosphate group contains a strong covalent bond that, when hydrolyzed, releases free energy. 
D)  Its terminal phosphate bond has higher energy than the other two. 
E)  It is one of the four building blocks for DNA synthesis. 
A)  Its hydrolysis provides an input of free energy for exergonic reactions. 
B)  It provides energy coupling between exergonic and endergonic reactions. 
C)  Its terminal phosphate group contains a strong covalent bond that, when hydrolyzed, releases free energy. 
D)  Its terminal phosphate bond has higher energy than the other two. 
E)  It is one of the four building blocks for DNA synthesis.

Question 13

Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as a(n)

Accepted Answer

A)  competitive inhibitor of the enzyme. 
B)  noncompetitive inhibitor of the enzyme. 
C)  allosteric activator of the enzyme. 
D)  cofactor necessary for enzyme activity. 
E)  coenzyme derived from a vitamin. 
A)  competitive inhibitor of the enzyme. 
B)  noncompetitive inhibitor of the enzyme. 
C)  allosteric activator of the enzyme. 
D)  cofactor necessary for enzyme activity. 
E)  coenzyme derived from a vitamin.

Question 14

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 15

A number of systems for pumping ions across membranes are powered by ATP. Such ATP-powered pumps are often called ATPases although they don't often hydrolyze ATP unless they are simultaneously transporting ions. Because small increases in calcium ions in the cytosol can trigger a number of different intracellular reactions, cells keep the cytosolic calcium concentration quite low under normal conditions, using ATP-powered calcium pumps. For example, muscle cells transport calcium from the cytosol into the membranous system called the sarcoplasmic reticulum (SR). If a resting muscle cell's cytosol has a free calcium ion concentration of 10⁻⁷ while the concentration in the SR is 10⁻², then how is the ATPase acting?

Accepted Answer

A)  ATPase activity must be powering an inflow of calcium from the outside of the cell into the SR. 
B)  ATPase activity must be transferring   ᵢ to the SR to enable this to occur. 
C)  ATPase activity must be pumping calcium from the cytosol to the SR against the concentration gradient. 
D)  ATPase activity must be opening a channel for the calcium ions to diffuse back into the SR along the concentration gradient. 
E)  ATPase activity must be routing calcium ions from the SR to the cytosol, and then to the cell's environment. 
A)  ATPase activity must be powering an inflow of calcium from the outside of the cell into the SR. 
B)  ATPase activity must be transferring   ᵢ to the SR to enable this to occur. 
C)  ATPase activity must be pumping calcium from the cytosol to the SR against the concentration gradient. 
D)  ATPase activity must be opening a channel for the calcium ions to diffuse back into the SR along the concentration gradient. 
E)  ATPase activity must be routing calcium ions from the SR to the cytosol, and then to the cell's environment.

Question 16

Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?

Accepted Answer

A)  denaturization of the enzyme 
B)  allosteric inhibition 
C)  competitive inhibition 
D)  saturation of the enzyme activity 
E)  insufficient cofactors 
A)  denaturization of the enzyme 
B)  allosteric inhibition 
C)  competitive inhibition 
D)  saturation of the enzyme activity 
E)  insufficient cofactors

Question 17

Which of the following statements regarding enzymes is true?

Accepted Answer

A)  Enzymes increase the rate of a reaction by making the reaction more exergonic. 
B)  Enzymes increase the rate of a reaction by lowering the activation energy barrier. 
C)  Enzymes increase the rate of a reaction by reducing the rate of reverse reactions. 
D)  Enzymes change the equilibrium point of the reactions they catalyze. 
E)  Enzymes make the rate of a reaction independent of substrate concentrations. 
A)  Enzymes increase the rate of a reaction by making the reaction more exergonic. 
B)  Enzymes increase the rate of a reaction by lowering the activation energy barrier. 
C)  Enzymes increase the rate of a reaction by reducing the rate of reverse reactions. 
D)  Enzymes change the equilibrium point of the reactions they catalyze. 
E)  Enzymes make the rate of a reaction independent of substrate concentrations.

Question 18

Which of the following is true of enzymes?

Accepted Answer

A)  Nonprotein cofactors alter the substrate specificity of enzymes. 
B)  Enzyme function is increased if the 3-D structure or conformation of an enzyme is altered. 
C)  Enzyme function is independent of physical and chemical environmental factors such as pH and temperature. 
D)  Enzymes increase the rate of chemical reaction by lowering activation energy barriers. 
E)  Enzymes increase the rate of chemical reaction by providing activation energy to the substrate. 
A)  Nonprotein cofactors alter the substrate specificity of enzymes. 
B)  Enzyme function is increased if the 3-D structure or conformation of an enzyme is altered. 
C)  Enzyme function is independent of physical and chemical environmental factors such as pH and temperature. 
D)  Enzymes increase the rate of chemical reaction by lowering activation energy barriers. 
E)  Enzymes increase the rate of chemical reaction by providing activation energy to the substrate.

Question 19

Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?

Accepted Answer

A)  catalysis 
B)  metabolism 
C)  anabolism 
D)  dehydration 
E)  catabolism 
A)  catalysis 
B)  metabolism 
C)  anabolism 
D)  dehydration 
E)  catabolism

Question 20

For the hydrolysis of ATP to ADP +   ᵢ, the free energy change is -7.3 kcal/mol under standard conditions (1 M concentration of both reactants and products). In the cellular environment, however, the free energy change is about -13 kcal/mol. What can we conclude about the free energy change for the formation of ATP from ADP and   ᵢ under cellular conditions?

Accepted Answer

A)  It is +7.3 kcal/mol. 
B)  It is less than +7.3 kcal/mol. 
C)  It is about +13 kcal/mol. 
D)  It is greater than +13 kcal/mol. 
E)  The information given is insufficient to deduce the free energy change. 
A)  It is +7.3 kcal/mol. 
B)  It is less than +7.3 kcal/mol. 
C)  It is about +13 kcal/mol. 
D)  It is greater than +13 kcal/mol. 
E)  The information given is insufficient to deduce the free energy change.

Exam 8: An Introduction to Metabolism

Which of the following is true of metabolism in its entirety in all organisms?

A system at chemical equilibrium

Biological evolution of life on Earth, from simple prokaryote-like cells to large, multicellar eukaryotic organisms,

The following questions are from the end-of-chapter "Test Your Understanding" section in Chapter 8 of the textbook. -Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as ________ is to ________.

Which of the following statements is true about enzyme-catalyzed reactions?

What is the difference (if any)between the structure of ATP and the structure of the precursor of the A nucleotide in RNA?

The following questions are from the end-of-chapter "Test Your Understanding" section in Chapter 8 of the textbook. -Some bacteria are metabolically active in hot springs because

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

For living organisms, which of the following is an important consequence of the first law of thermodynamics?

Mutations that result in single amino acid substitutions in an enzyme

Why is ATP an important molecule in metabolism?

Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as a(n)

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

Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?

Which of the following statements regarding enzymes is true?

Which of the following is true of enzymes?

Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?

Introduction: Themes in the Study of Life

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

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 Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

Filters

The following questions are from the end-of-chapter "Test Your Understanding" section in Chapter 8 of the textbook. -Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as is to .