Question 1

-How do cells use the ATP cycle shown in the figure?

Accepted Answer

A)  Cells use the cycle to recycle ADP and phosphate. 
B)  Cells use the cycle to recycle energy released by ATP hydrolysis. 
C)  Cells use the cycle to recycle ADP, phosphate, and the energy released by ATP hydrolysis. 
D)  Cells use the cycle to generate or consume water molecules as needed. 
E)  Cells use the cycle primarily to generate heat. 
A)  Cells use the cycle to recycle ADP and phosphate. 
B)  Cells use the cycle to recycle energy released by ATP hydrolysis. 
C)  Cells use the cycle to recycle ADP, phosphate, and the energy released by ATP hydrolysis. 
D)  Cells use the cycle to generate or consume water molecules as needed. 
E)  Cells use the cycle primarily to generate heat.

Question 2

-Which of the following is the most correct interpretation of the accompanying 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 + Pi 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)  Pi 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 + Pi 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)  Pi acts as a shuttle molecule to move energy from ATP to ADP.

Question 3

A noncompetitive inhibitor decreases the rate of an enzyme reaction by ________.

Accepted Answer

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

Question 4

How might a change of one amino acid at a site, distant from the active site of an enzyme, alter an 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 an enzyme 
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 an enzyme 
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 5

When ATP releases some energy, it also releases inorganic phosphate. What happens to the inorganic phosphate in the cell?

Accepted Answer

A)  It is secreted as waste. 
B)  It is used only to regenerate more ATP. 
C)  It is added to water and excreted as a liquid. 
D)  It may be used to form a phosphorylated intermediate. 
E)  It enters the nucleus and affects gene expression. 
A)  It is secreted as waste. 
B)  It is used only to regenerate more ATP. 
C)  It is added to water and excreted as a liquid. 
D)  It may be used to form a phosphorylated intermediate. 
E)  It enters the nucleus and affects gene expression.

Question 6

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 7

Mutations that result in a single amino acid substitution in an enzyme ________.

Accepted Answer

A)  cannot affect the activity or properties of the enzyme 
B)  will destroy the activity of the enzyme 
C)  will change the substrate specificity of the enzyme 
D)  may change the enzyme's optimal temperature or optimal pH 
E)  may, in rare cases, cause the enzyme to run reactions in reverse 
A)  cannot affect the activity or properties of the enzyme 
B)  will destroy the activity of the enzyme 
C)  will change the substrate specificity of the enzyme 
D)  may change the enzyme's optimal temperature or optimal pH 
E)  may, in rare cases, cause the enzyme to run reactions in reverse

Question 8

The active site of an enzyme is the region that ________.

Accepted Answer

A)  binds allosteric regulators of the enzyme 
B)  is involved in the catalytic reaction of the enzyme 
C)  binds noncompetitive inhibitors of the enzyme 
D)  is inhibited by the presence of a coenzyme or a cofactor 
A)  binds allosteric regulators of the enzyme 
B)  is involved in the catalytic reaction of the enzyme 
C)  binds noncompetitive inhibitors of the enzyme 
D)  is inhibited by the presence of a coenzyme or a cofactor

Question 9

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 10

Enzymes ________.

Accepted Answer

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

Question 11

Activity of various enzymes at various temperatures (a) and at various pH (b).
-Which curves on the accompanying 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 12

The following question(s) are based on the reaction A + B ↔ C + D shown in the accompanying figure.  
-Which of the following represents the ΔG of the reaction in the figure?

Accepted Answer

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

Question 13

Catabolic pathways ________.

Accepted Answer

A)  combine molecules into more energy-rich molecules 
B)  supply energy, primarily in the form of ATP, for the cell's work 
C)  are endergonic 
D)  are spontaneous and do not need enzyme catalysis 
E)  build up complex molecules such as protein from simpler compounds 
A)  combine molecules into more energy-rich molecules 
B)  supply energy, primarily in the form of ATP, for the cell's work 
C)  are endergonic 
D)  are spontaneous and do not need enzyme catalysis 
E)  build up complex molecules such as protein from simpler compounds

Question 14

Which of the following is a statement of the first law of thermodynamics?

Accepted Answer

A)  Energy cannot be created or destroyed. 
B)  The entropy of the universe is decreasing. 
C)  The entropy of the universe is constant. 
D)  Kinetic energy is stored energy that results from the specific arrangement of matter. 
E)  Energy cannot be transferred or transformed. 
A)  Energy cannot be created or destroyed. 
B)  The entropy of the universe is decreasing. 
C)  The entropy of the universe is constant. 
D)  Kinetic energy is stored energy that results from the specific arrangement of matter. 
E)  Energy cannot be transferred or transformed.

Question 15

Activity of various enzymes at various temperatures (a) and at various pH (b).
-Which temperature and pH profile curves on the graphs were most likely generated from analysis of an enzyme from a human stomach where conditions are strongly acid?

Accepted Answer

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

Question 16

Which of the following statements is representative of the second law of thermodynamics?

Accepted Answer

A)  Conversion of energy from one form to another is always accompanied by some gain of free energy. 
B)  Heat represents a form of energy that can be used by most organisms to do work. 
C)  Without an input of energy, organisms would tend toward decreasing entropy. 
D)  Cells require a constant input of energy to maintain their high level of organization. 
E)  Every energy transformation by a cell decreases the entropy of the universe. 
A)  Conversion of energy from one form to another is always accompanied by some gain of free energy. 
B)  Heat represents a form of energy that can be used by most organisms to do work. 
C)  Without an input of energy, organisms would tend toward decreasing entropy. 
D)  Cells require a constant input of energy to maintain their high level of organization. 
E)  Every energy transformation by a cell decreases the entropy of the universe.

Question 17

The lock-and-key analogy for enzymes applies to the specificity of enzymes ________.

Accepted Answer

A)  as they form their tertiary structure 
B)  as they form their tertiary and quaternary structure 
C)  binding to their substrate 
D)  interacting with water 
E)  interacting with ions 
A)  as they form their tertiary structure 
B)  as they form their tertiary and quaternary structure 
C)  binding to their substrate 
D)  interacting with water 
E)  interacting with ions

Question 18

Anabolic pathways ________.

Accepted Answer

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

Question 19

-Which of the following is TRUE when comparing an uncatalyzed reaction to the same reaction with a catalyst?

Accepted Answer

A)  The catalyzed reaction will be slower. 
B)  The catalyzed reaction will have the same ∆G. 
C)  The catalyzed reaction will have higher activation energy. 
D)  The catalyzed reaction will consume all of the catalyst. 
A)  The catalyzed reaction will be slower. 
B)  The catalyzed reaction will have the same ∆G. 
C)  The catalyzed reaction will have higher activation energy. 
D)  The catalyzed reaction will consume all of the catalyst.

Question 20

Biological evolution of life on Earth, from simple prokaryote-like cells to large, multicellular 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

Exam 8: Energy and Enzymes: an Introduction to Metabolism

-How do cells use the ATP cycle shown in the figure?

-Which of the following is the most correct interpretation of the accompanying figure?

A noncompetitive inhibitor decreases the rate of an enzyme reaction by ________.

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

When ATP releases some energy, it also releases inorganic phosphate. What happens to the inorganic phosphate in the cell?

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

Mutations that result in a single amino acid substitution in an enzyme ________.

The active site of an enzyme is the region that ________.

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

Enzymes ________.

Activity of various enzymes at various temperatures (a) and at various pH (b). -Which curves on the accompanying 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?

The following question(s) are based on the reaction A + B ↔ C + D shown in the accompanying figure. -Which of the following represents the ΔG of the reaction in the figure?

Catabolic pathways ________.

Which of the following is a statement of the first law of thermodynamics?

Activity of various enzymes at various temperatures (a) and at various pH (b). -Which temperature and pH profile curves on the graphs were most likely generated from analysis of an enzyme from a human stomach where conditions are strongly acid?

Which of the following statements is representative of the second law of thermodynamics?

The lock-and-key analogy for enzymes applies to the specificity of enzymes ________.

Anabolic pathways ________.

-Which of the following is TRUE when comparing an uncatalyzed reaction to the same reaction with a catalyst?

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

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Ecosystems and Global Ecology

Lipids, Membranes, and the First Cells

Inside the Cell

Cellular Respiration and Fermentation

Photosynthesis

Cellcell Interactions

The Cell Cycle

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

How Genes Work

Transcription, Rna Processing, and Translation

Control of Gene Expression in Bacteria

Control of Gene Expression in Eukaryotes

The Molecular Revolution: Biotechnology and Beyond

Genes, Development, and Evolution

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

Bacteria and Archaea

Protists

Green Algae and Land Plants

Fungi

An Introduction to Animals

Protostome Animals

Deuterostome Animals

Viruses

Plant Form and Function

Water and Sugar Transport in Plants

Plant Nutrition

Plant Sensory Systems, Signals, and Responses

Plant Reproduction and Development

Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Animal Nervous Systems

Animal Sensory Systems

Animal Movement

Chemical Signals in Animals

Animal Reproduction and Development

The Immune System in Animals

An Introduction to Ecology

Behavioral Ecology

Population Ecology

Community Ecology

Biodiversity and Conservation Biology

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