Question 1

Use the figure below to answer the following questions).
  
-How do cells use the ATP cycle shown in the figure above?

Accepted Answer

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

Question 2

The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as ___________inhibition.

Accepted Answer

A)  feedback 
B)  reversible 
C)  allosteric 
D)  noncooperative 
E)  metabolic 
A)  feedback 
B)  reversible 
C)  allosteric 
D)  noncooperative 
E)  metabolic A

Question 3

The following questions) are based on the reaction A + B -C + D shown in the figure provided.
  
-Which of the following represents the activation energy needed for the enzyme- catalyzed reverse reaction, C +
D -A + B, 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 A

Question 4

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

Accepted Answer

A)  catabolism catabolic pathways) 
B)  metabolism 
C)  anabolism anabolic pathways) 
D)  denaturation 
E)  dehydration 
A)  catabolism catabolic pathways) 
B)  metabolism 
C)  anabolism anabolic pathways) 
D)  denaturation 
E)  dehydration

Question 5

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

Question 6

When 10 000 molecules of ATP are hydrolyzed to ADP and i in a test tube, about half 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)  The hydrolysis of ATP in a cell produces different chemical products than does the reaction in a test tube. 
B)  Reactant and product concentrations in the test tube are different from those in the cell. 
C)  The reaction in cells must be catalyzed by enzymes, but the reaction in a test tube does not need enzymes. 
D)  Cells are less efficient at heat production than nonliving systems. 
E)  Cells are open systems, but a test tube is an isolated system. 
A)  The hydrolysis of ATP in a cell produces different chemical products than does the reaction in a test tube. 
B)  Reactant and product concentrations in the test tube are different from those in the cell. 
C)  The reaction in cells must be catalyzed by enzymes, but the reaction in a test tube does not need enzymes. 
D)  Cells are less efficient at heat production than nonliving systems. 
E)  Cells are open systems, but a test tube is an isolated system.

Question 7

The following questions) are based on the reaction A + B -C + D shown in the figure provided.
  
-Which of the following represents the activation energy needed for the noncatalyzed reverse reaction, C + D -A
+ B, 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 8

Rate of an enzyme- catalyzed reaction as a function of varying reactant concentration, with the concentration of enzyme constant.
In the graph provided, why does the reaction rate plateau at higher reactant concentrations?

Accepted Answer

A)  The rate of the reverse reaction increases with reactant concentration. 
B)  The reaction nears equilibrium at high reactant concentrations. 
C)  Feedback inhibition by product occurs at high reactant concentrations. 
D)  The activation energy for the reaction increases with reactant concentration. 
E)  Most enzyme molecules are occupied by substrate at high reactant concentrations. 
A)  The rate of the reverse reaction increases with reactant concentration. 
B)  The reaction nears equilibrium at high reactant concentrations. 
C)  Feedback inhibition by product occurs at high reactant concentrations. 
D)  The activation energy for the reaction increases with reactant concentration. 
E)  Most enzyme molecules are occupied by substrate at high reactant concentrations.

Question 9

Which of the following is true for all exergonic reactions?

Accepted Answer

A)  The reaction goes only in a forward direction: All reactants will be converted to products, but no products will be converted to reactants. 
B)  A net input of energy from the surroundings is required for the reactions to proceed. 
C)  The reactions are rapid. 
D)  The reaction proceeds with a net release of free energy. 
E)  The products have more total energy than the reactants. 
A)  The reaction goes only in a forward direction: All reactants will be converted to products, but no products will be converted to reactants. 
B)  A net input of energy from the surroundings is required for the reactions to proceed. 
C)  The reactions are rapid. 
D)  The reaction proceeds with a net release of free energy. 
E)  The products have more total energy than the reactants.

Question 10

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

Accepted Answer

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

Question 11

HIV is the virus that causes AIDS. In the mid- 1990s, researchers discovered an enzyme in HIV called protease. Once the enzyme's structure was known, researchers began looking for drugs that would fit into the active site and block it. If this strategy for stopping HIV infections were successful, it would be an example of what phenomenon?

Accepted Answer

A)  allosteric regulation 
B)  denaturation 
C)  vaccination 
D)  feedback inhibition 
E)  competitive inhibition 
A)  allosteric regulation 
B)  denaturation 
C)  vaccination 
D)  feedback inhibition 
E)  competitive inhibition

Question 12

Whenever energy is transformed, there is always an increase in the

Accepted Answer

A)  entropy of the universe. 
B)  free energy of the universe. 
C)  free energy of the system. 
D)  enthalpy of the universe. 
E)  entropy of the system. 
A)  entropy of the universe. 
B)  free energy of the universe. 
C)  free energy of the system. 
D)  enthalpy of the universe. 
E)  entropy of the system.

Question 13

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

Accepted Answer

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

Question 14

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

Accepted Answer

A)  competitive inhibition 
B)  high activation energy 
C)  the need for a coenzyme 
D)  insufficient cofactors 
E)  allosteric inhibition 
A)  competitive inhibition 
B)  high activation energy 
C)  the need for a coenzyme 
D)  insufficient cofactors 
E)  allosteric inhibition

Question 15

Enthalpy H) is the

Accepted Answer

A)  system's entropy. 
B)  total kinetic energy of a system. 
C)  cell's energy equilibrium. 
D)  condition of a cell that is not able to react. 
E)  total energy in biological systems. 
A)  system's entropy. 
B)  total kinetic energy of a system. 
C)  cell's energy equilibrium. 
D)  condition of a cell that is not able to react. 
E)  total energy in biological systems.

Question 16

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

Accepted Answer

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

Question 17

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

Accepted Answer

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

Question 18

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

Question 19

The following questions) are based on the reaction A + B -C + D shown in the figure provided.
  
-Which of the following terms best describes the forward reaction in the figure?

Accepted Answer

A)  endergonic, AG > 0 
B)  endergonic, AG  0 
A)  endergonic, AG > 0 
B)  endergonic, AG  0

Question 20

Activity of various enzymes at various temperatures a) and at various pH b). Use the image above to answer the following
questions).
-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 5 
B)  curves 1 and 4 
C)  curves 3 and 4 
D)  curves 2 and 4 
E)  curves 2 and 5 
A)  curves 1 and 5 
B)  curves 1 and 4 
C)  curves 3 and 4 
D)  curves 2 and 4 
E)  curves 2 and 5

Exam 8: Energy and Enzymes

Use the figure below to answer the following questions). -How do cells use the ATP cycle shown in the figure above?

The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as ___________inhibition.

The following questions) are based on the reaction A + B -C + D shown in the figure provided. -Which of the following represents the activation energy needed for the enzyme- catalyzed reverse reaction, C + D -A + B, in the figure?

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

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

When 10 000 molecules of ATP are hydrolyzed to ADP and i in a test tube, about half 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?

The following questions) are based on the reaction A + B -C + D shown in the figure provided. -Which of the following represents the activation energy needed for the noncatalyzed reverse reaction, C + D -A + B, in the figure?

Rate of an enzyme- catalyzed reaction as a function of varying reactant concentration, with the concentration of enzyme constant. In the graph provided, why does the reaction rate plateau at higher reactant concentrations?

Which of the following is true for all exergonic reactions?

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

Whenever energy is transformed, there is always an increase in the

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

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

Enthalpy H) is the

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

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

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?

The following questions) are based on the reaction A + B -C + D shown in the figure provided. -Which of the following terms best describes the forward reaction in the figure?

Activity of various enzymes at various temperatures a) and at various pH b). Use the image above to answer the following questions). -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?

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

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

Gene Structure and Development

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

Behavioural Ecology

Population Ecology

Community Ecology

Ecosystems and Global Ecology

Biodiversity and Conservation Biology

Filters

When 10 000 molecules of ATP are hydrolyzed to ADP and _iin a test tube, about half 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?