Question 1

Which of the following is (are)true for anabolic pathways?

Accepted Answer

A) They do not depend on enzymes. 
B) They are usually highly spontaneous chemical reactions. 
C) They consume energy to build up polymers from monomers. 
D) They release energy as they degrade polymers to monomers. 
E) They consume energy to decrease the entropy of the organism and its environment. 
A) They do not depend on enzymes. 
B) They are usually highly spontaneous chemical reactions. 
C) They consume energy to build up polymers from monomers. 
D) They release energy as they degrade polymers to monomers. 
E) They consume energy to decrease the entropy of the organism and its environment.

Question 2

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 3

A reaction that absorbs free energy from its surroundings is a(n)________ reaction.

Accepted Answer

A) spontaneous 
B) endothermic 
C) exothermic 
D) endergonic 
E) exergonic 
A) spontaneous 
B) endothermic 
C) exothermic 
D) endergonic 
E) exergonic

Question 4

Which of the following shows the correct changes in thermodynamic properties for a chemical reaction in which amino acids are linked to form a protein?

Accepted Answer

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

Question 5

Which of the following statements is a logical consequence of the second law of thermodynamics?

Accepted Answer

A) If the entropy of a system increases, there must be a corresponding decrease in the entropy of the universe. 
B) If there is an increase in the energy of a system, there must be a corresponding decrease in the energy of the rest of the universe. 
C) Every energy transfer requires activation energy from the environment. 
D) Every chemical reaction must increase the total entropy of the universe. 
E) Energy can be transferred or transformed, but it cannot be created or destroyed. 
A) If the entropy of a system increases, there must be a corresponding decrease in the entropy of the universe. 
B) If there is an increase in the energy of a system, there must be a corresponding decrease in the energy of the rest of the universe. 
C) Every energy transfer requires activation energy from the environment. 
D) Every chemical reaction must increase the total entropy of the universe. 
E) Energy can be transferred or transformed, but it cannot be created or destroyed.

Question 6

Which of the following best describes enthalpy (H)?

Accepted Answer

A) the total kinetic energy of a system 
B) the heat content of a chemical system 
C) the system's entropy 
D) the cell's energy equilibrium 
E) the condition of a cell that is not able to react 
A) the total kinetic energy of a system 
B) the heat content of a chemical system 
C) the system's entropy 
D) the cell's energy equilibrium 
E) the condition of a cell that is not able to react

Question 7

Use the following information to answer the questions below.
Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the ratio of succinate to malonic acid reduces the inhibitory effect of malonic acid.
-What is malonic acid's role with respect to succinate dehydrogenase?

Accepted Answer

A) It is a competitive inhibitor. 
B) It blocks the binding of fumarate. 
C) It is a noncompetitive inhibitor. 
D) It is able to bind to succinate. 
E) It is an allosteric regulator. 
A) It is a competitive inhibitor. 
B) It blocks the binding of fumarate. 
C) It is a noncompetitive inhibitor. 
D) It is able to bind to succinate. 
E) It is an allosteric regulator.

Question 8

How might an amino acid change at a site distant from the active site of the enzyme alter the enzyme's substrate specificity?

Accepted Answer

A) by changing the enzyme's stability 
B) by changing the enzyme's location in the cell 
C) by changing the shape of the protein 
D) by changing the enzyme's pH optimum 
E) an amino acid change away from the active site cannot alter the enzyme's substrate specificity 
A) by changing the enzyme's stability 
B) by changing the enzyme's location in the cell 
C) by changing the shape of the protein 
D) by changing the enzyme's pH optimum 
E) an amino acid change away from the active site cannot alter the enzyme's substrate specificity

Question 9

In experimental tests of enzyme evolution, in which a gene encoding an enzyme is subjected to multiple cycles of random mutagenesis and selection for altered substrate specificity, the resulting enzyme had multiple amino acid changes associated with altered substrate specificity. Where in the enzyme were these amino acid changes located?

Accepted Answer

A) only in the active site 
B) only in the active site or near the active site 
C) in or near the active site and at surface sites away from the active site 
D) only at surface sites away from the active site 
E) only in the hydrophobic interior of the folded protein 
A) only in the active site 
B) only in the active site or near the active site 
C) in or near the active site and at surface sites away from the active site 
D) only at surface sites away from the active site 
E) only in the hydrophobic interior of the folded protein

Question 10

Chemical equilibrium is relatively rare in living cells. Which of the following could be an example of a reaction at chemical equilibrium in a cell?

Accepted Answer

A) a reaction in which the free energy at equilibrium is higher than the energy content at any point away from equilibrium 
B) a chemical reaction in which the entropy change in the reaction is just balanced by an opposite entropy change in the cell's surroundings 
C) an endergonic reaction in an active metabolic pathway where the energy for that reaction is supplied only by heat from the environment 
D) a chemical reaction in which both the reactants and products are not being produced or used in any active metabolic pathway 
E) no possibility of having chemical equilibrium in any living cell 
A) a reaction in which the free energy at equilibrium is higher than the energy content at any point away from equilibrium 
B) a chemical reaction in which the entropy change in the reaction is just balanced by an opposite entropy change in the cell's surroundings 
C) an endergonic reaction in an active metabolic pathway where the energy for that reaction is supplied only by heat from the environment 
D) a chemical reaction in which both the reactants and products are not being produced or used in any active metabolic pathway 
E) no possibility of having chemical equilibrium in any living cell

Question 11

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 12

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 13

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 14

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 15

When you have a severe fever, what grave consequence may occur if the fever is not controlled?

Accepted Answer

A) destruction of your enzymes' primary structure 
B) removal of amine groups from your proteins 
C) change in the tertiary structure of your enzymes 
D) removal of the amino acids in active sites of your enzymes 
E) binding of your enzymes to inappropriate substrates 
A) destruction of your enzymes' primary structure 
B) removal of amine groups from your proteins 
C) change in the tertiary structure of your enzymes 
D) removal of the amino acids in active sites of your enzymes 
E) binding of your enzymes to inappropriate substrates

Question 16

Energy coupling occurs when

Accepted Answer

A) an endergonic reaction drives an exergonic reaction. 
B) an exergonic reaction drives an endergonic reaction. 
C) heat is generated. 
D) allosteric interactions are at work. 
E) chemical equilibrium is reached. 
A) an endergonic reaction drives an exergonic reaction. 
B) an exergonic reaction drives an endergonic reaction. 
C) heat is generated. 
D) allosteric interactions are at work. 
E) chemical equilibrium is reached.

Question 17

A chemical agent that speeds up a reaction without being consumed during the reaction is known as a(n)

Accepted Answer

A) enhancer 
B) substrate 
C) co-enzyme 
D) reactant 
E) catalyst 
A) enhancer 
B) substrate 
C) co-enzyme 
D) reactant 
E) catalyst

Question 18

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 19

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 20

Some of the drugs used to treat HIV patients are competitive inhibitors of the HIV reverse transcriptase enzyme. Unfortunately, the high mutation rate of HIV means that the virus rapidly acquires mutations with amino acid changes that make it resistant to these competitive inhibitors. Where in the reverse transcriptase enzyme would such amino acid changes most likely occur in drug-resistant viruses?

Accepted Answer

A) in or near the active site 
B) at an allosteric site 
C) at a cofactor binding site 
D) in regions of the protein that determine packaging into the virus capsid 
E) such mutations could occur anywhere with equal probability 
A) in or near the active site 
B) at an allosteric site 
C) at a cofactor binding site 
D) in regions of the protein that determine packaging into the virus capsid 
E) such mutations could occur anywhere with equal probability

Exam 8: An Introduction to Metabolism

Which of the following is (are)true for anabolic pathways?

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)

A reaction that absorbs free energy from its surroundings is a(n)________ reaction.

Which of the following shows the correct changes in thermodynamic properties for a chemical reaction in which amino acids are linked to form a protein?

Which of the following statements is a logical consequence of the second law of thermodynamics?

Which of the following best describes enthalpy (H)?

How might an amino acid change at a site distant from the active site of the enzyme alter the enzyme's substrate specificity?

Chemical equilibrium is relatively rare in living cells. Which of the following could be an example of a reaction at chemical equilibrium in a cell?

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

Which of the following is true of enzymes?

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?

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

When you have a severe fever, what grave consequence may occur if the fever is not controlled?

Energy coupling occurs when

A chemical agent that speeds up a reaction without being consumed during the reaction is known as a(n)

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

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

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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