Question 1

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

Question 2

An important group of peripheral membrane proteins are enzymes such as the phospholipases that cleave the head groups of phospholipids. What properties must these enzymes exhibit?

Accepted Answer

A)  lipid solubility 
B)  resistance to degradation 
C)  water solubility 
D)  independence from cofactor interaction 
E)  membrane- spanning domains 
A)  lipid solubility 
B)  resistance to degradation 
C)  water solubility 
D)  independence from cofactor interaction 
E)  membrane- spanning domains

Question 3

A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because

Accepted Answer

A)  starch cannot be hydrolyzed in the presence of so much water. 
B)  starch hydrolysis is nonspontaneous. 
C)  the starch solution has less free energy than the sugar solution. 
D)  the activation energy barrier for this reaction cannot easily be surmounted at room temperature. 
E)  the hydrolysis of starch to sugar is endergonic. 
A)  starch cannot be hydrolyzed in the presence of so much water. 
B)  starch hydrolysis is nonspontaneous. 
C)  the starch solution has less free energy than the sugar solution. 
D)  the activation energy barrier for this reaction cannot easily be surmounted at room temperature. 
E)  the hydrolysis of starch to sugar is endergonic.

Question 4

The following questions) are based on the reaction A + B -C + D shown in the figure provided.
  
-Which of the following represents the OG 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 5

The active site of an enzyme is the region that

Accepted Answer

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

Question 6

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

Accepted Answer

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

Question 7

Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics?

Accepted Answer

A)  Living organisms do not obey the second law of thermodynamics, which states that entropy must increase with time. 
B)  Living organisms are able to transform energy into entropy. 
C)  As a consequence of growing, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their growth. 
D)  Living organisms do not follow the laws of thermodynamics. 
E)  Living organisms are able to transform entropy into energy. 
A)  Living organisms do not obey the second law of thermodynamics, which states that entropy must increase with time. 
B)  Living organisms are able to transform energy into entropy. 
C)  As a consequence of growing, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their growth. 
D)  Living organisms do not follow the laws of thermodynamics. 
E)  Living organisms are able to transform entropy into energy.

Question 8

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

Question 9

A chemical reaction that has a positive OG is best described as

Accepted Answer

A)  entropic. 
B)  endergonic. 
C)  enthalpic. 
D)  exergonic. 
E)  spontaneous. 
A)  entropic. 
B)  endergonic. 
C)  enthalpic. 
D)  exergonic. 
E)  spontaneous.

Question 10

You have isolated a previously unstudied protein, identified its complete structure in detail, and determined that it catalyzes the breakdown of a large substrate. You notice it has two binding sites. One of these is large, apparently the binding site for the large substrate; the other is small, possibly a binding site for a regulatory molecule. What do these findings tell you about the mechanism of this protein?

Accepted Answer

A)  It is probably an enzyme that works through allosteric regulation. 
B)  It is probably a structural protein found in cartilage or skeletal tissue. 
C)  It is probably an enzyme that works through competitive inhibition. 
D)  It is probably a cell membrane transport protein-like an ion channel. 
E)  It is probably a structural protein that is involved in cell- to- cell adhesion. 
A)  It is probably an enzyme that works through allosteric regulation. 
B)  It is probably a structural protein found in cartilage or skeletal tissue. 
C)  It is probably an enzyme that works through competitive inhibition. 
D)  It is probably a cell membrane transport protein-like an ion channel. 
E)  It is probably a structural protein that is involved in cell- to- cell adhesion.

Question 11

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 required for a noncatalyzed 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 12

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

Accepted Answer

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

Question 13

Enzymes

Accepted Answer

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

Question 14

Which of the following is true of enzymes?

Accepted Answer

A)  Enzymes increase the rate of chemical reaction by providing activation energy to the substrate. 
B)  Enzyme function is increased if the three- dimensional structure or conformation of an enzyme is altered. 
C)  Enzymes increase the rate of chemical reaction by increasing AG. 
D)  Enzyme function is independent of physical and chemical environmental factors such as pH and temperature. 
E)  Enzymes increase the rate of chemical reaction by the lowering activation energy required. 
A)  Enzymes increase the rate of chemical reaction by providing activation energy to the substrate. 
B)  Enzyme function is increased if the three- dimensional structure or conformation of an enzyme is altered. 
C)  Enzymes increase the rate of chemical reaction by increasing AG. 
D)  Enzyme function is independent of physical and chemical environmental factors such as pH and temperature. 
E)  Enzymes increase the rate of chemical reaction by the lowering activation energy required.

Question 15

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

Accepted Answer

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

Question 16

A system at chemical equilibrium

Accepted Answer

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

Question 17

Use the following information to answer the corresponding questions).
A series of enzymes catalyze the reaction X -Y -Z -A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme.
-With respect to the enzyme that converts X to Y, substance A functions as

Accepted Answer

A)  a competitive inhibitor. 
B)  an allosteric inhibitor. 
C)  an intermediate. 
D)  the substrate. 
E)  a coenzyme. 
A)  a competitive inhibitor. 
B)  an allosteric inhibitor. 
C)  an intermediate. 
D)  the substrate. 
E)  a coenzyme.

Question 18

You have discovered an enzyme that can catalyze two different chemical reactions. Which of the following is most likely to be correct?

Accepted Answer

A)  Two types of allosteric regulation occur: the binding of one molecule activates the enzyme while the binding of a different molecule inhibits it. 
B)  The enzyme must be flexible and composed of two different subunits. 
C)  Either the enzyme has two distinct active sites or the reactants involved in the two reactions are very similar in size and shape. 
D)  The enzyme contains a- helices and fi- pleated sheets. 
E)  The enzyme is subject to competitive inhibition and allosteric regulation. 
A)  Two types of allosteric regulation occur: the binding of one molecule activates the enzyme while the binding of a different molecule inhibits it. 
B)  The enzyme must be flexible and composed of two different subunits. 
C)  Either the enzyme has two distinct active sites or the reactants involved in the two reactions are very similar in size and shape. 
D)  The enzyme contains a- helices and fi- pleated sheets. 
E)  The enzyme is subject to competitive inhibition and allosteric regulation.

Question 19

Some bacteria are metabolically active in hot springs because

Accepted Answer

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

Question 20

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

Accepted Answer

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

Exam 8: Energy and Enzymes

Catabolic pathways

An important group of peripheral membrane proteins are enzymes such as the phospholipases that cleave the head groups of phospholipids. What properties must these enzymes exhibit?

A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because

The following questions) are based on the reaction A + B -C + D shown in the figure provided. -Which of the following represents the OG of the reaction in the figure?

The active site of an enzyme is the region that

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

Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics?

A chemical reaction that has a positive OG is best described as

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 required for a noncatalyzed reaction in the figure?

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

Enzymes

Which of the following is true of enzymes?

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

A system at chemical equilibrium

You have discovered an enzyme that can catalyze two different chemical reactions. Which of the following is most likely to be correct?

Some bacteria are metabolically active in hot springs because

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

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

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