Question 1

The end product of a biosynthetic pathway often acts to block the initial step in that pathway. This phenomenon is called

Accepted Answer

A)  substrate activation. 
B)  feedback inhibition. 
C)  allosteric activation. 
D)  denaturation. 
E)  irreversible inhibition. 
A)  substrate activation. 
B)  feedback inhibition. 
C)  allosteric activation. 
D)  denaturation. 
E)  irreversible inhibition.

Question 2

Which of the following is the best description of a coupled reaction?

Accepted Answer

A)  Two reactions, where the product of the first reaction is the reactant of the second reaction 
B)  Two reactions that occur in the same organelle 
C)  Reactions that occur during sexual reproduction 
D)  Two reactions that occur simultaneously 
E)  A reaction that occurs right after another reaction 
A)  Two reactions, where the product of the first reaction is the reactant of the second reaction 
B)  Two reactions that occur in the same organelle 
C)  Reactions that occur during sexual reproduction 
D)  Two reactions that occur simultaneously 
E)  A reaction that occurs right after another reaction

Question 3

Imagine that you are conducting an experiment on an enzyme known as sucrase. This enzyme is synthesized and used by yeast cells to break down the disaccharide sucrose (table sugar) into the monosaccharides glucose and fructose. You decide to conduct an experiment to test whether the sucrase enzyme can break down the artificial sweetener sucralose. Sucralose (a "chlorinated" carbohydrate) has some chemical similarity to sucrose, but is different in that three of its hydroxyl groups are missing and replaced with chlorine atoms instead. Based on the details provided in this scenario, do you think the sucrase enzyme will be able to interact with sucr

Accepted Answer

A)  No; sucralose is an ion and not a true carbohydrate. 
B)  No; all enzymes are highly specific and can react with only a specific substrate. 
C)  Yes; enzymes such as sucrase are not specific for their substrate. 
D)  Yes; the enzymes in human cells can interact with artificial sweeteners as if they were sugars. 
A)  No; sucralose is an ion and not a true carbohydrate. 
B)  No; all enzymes are highly specific and can react with only a specific substrate. 
C)  Yes; enzymes such as sucrase are not specific for their substrate. 
D)  Yes; the enzymes in human cells can interact with artificial sweeteners as if they were sugars.

Question 4

ATP is an energy carrier. Where is the energy actually located?

Accepted Answer

A)  Between the sugar and the phosphate 
B)  Attached to the nucleotide 
C)  In the bonds between phosphate groups 
D)  Attached to the phosphate group 
E)  Inside the phosphate 
A)  Between the sugar and the phosphate 
B)  Attached to the nucleotide 
C)  In the bonds between phosphate groups 
D)  Attached to the phosphate group 
E)  Inside the phosphate

Question 5

The reactant in an enzyme- catalyzed reaction is the

Accepted Answer

A)  product. 
B)  allosteric inhibitor. 
C)  activation energy. 
D)  active site. 
E)  substrate. 
A)  product. 
B)  allosteric inhibitor. 
C)  activation energy. 
D)  active site. 
E)  substrate.

Question 6

Enzymes are important because they

Accepted Answer

A)  allow reactions to occur at body temperature. 
B)  increase the body temperature of organisms. 
C)  can enable organisms to evade the laws of thermodynamics. 
D)  are structural proteins that make up bodily tissues. 
E)  bind irreversibly to substrates. 
A)  allow reactions to occur at body temperature. 
B)  increase the body temperature of organisms. 
C)  can enable organisms to evade the laws of thermodynamics. 
D)  are structural proteins that make up bodily tissues. 
E)  bind irreversibly to substrates.

Question 7

During photosynthesis, plants convert light energy to chemical energy. This is an example of

Accepted Answer

A)  increasing entropy. 
B)  a spontaneous reaction. 
C)  the second law of thermodynamics. 
D)  chemical equilibrium. 
E)  the first law of thermodynamics. 
A)  increasing entropy. 
B)  a spontaneous reaction. 
C)  the second law of thermodynamics. 
D)  chemical equilibrium. 
E)  the first law of thermodynamics.

Question 8

The burning of sugars as fuels for runners is an example of a(n) _ _ chemical reaction, whereas the production of sugars during photosynthesis is an example of a(n) chemical reaction.

Accepted Answer

exergonic;

Question 9

Which of the following does NOT have much potential energy?

Accepted Answer

A)  A diver on a springboard 
B)  A glucose molecule 
C)  A ball that has rolled downhill and stopped 
D)  A 9- volt battery 
E)  A water droplet at the top of a waterfall 
A)  A diver on a springboard 
B)  A glucose molecule 
C)  A ball that has rolled downhill and stopped 
D)  A 9- volt battery 
E)  A water droplet at the top of a waterfall

Question 10

Why does increasing the temperature of a chemical reaction generally increase the rate of the reaction?

Accepted Answer

Increasing the temperature increases the

Question 11

Normally, a certain enzyme has maximum activity at 37°C, but once it has been heated to 100°C and then cooled back down to 37°C, the enzyme is no longer active. Why?

Accepted Answer

The enzyme's three- dimensiona

Question 12

Each of the following requires 12 carbon atoms. Which of the arrangements of carbon atoms has the greatest entropy?

Accepted Answer

A)  12 molecules of carbon dioxide, CO2 
B)  2 molecules of the monosaccharide glucose, C6H12O6 
C)  4 molecules of the monosaccharide pyruvate, C3H4O3 
D)  1 molecule of the disaccharide maltose, C12H22O11 
A)  12 molecules of carbon dioxide, CO2 
B)  2 molecules of the monosaccharide glucose, C6H12O6 
C)  4 molecules of the monosaccharide pyruvate, C3H4O3 
D)  1 molecule of the disaccharide maltose, C12H22O11

Question 13

All of the following are ways in which enzymes are regulated by the cell EXCEPT

Accepted Answer

A)  a heavy metal (such as lead) may block the enzymes non- active site. 
B)  by first synthesizing the enzyme in an inactive form. 
C)  by feedback inhibition. 
D)  a gene coding for the enzyme may be turned off. 
A)  a heavy metal (such as lead) may block the enzymes non- active site. 
B)  by first synthesizing the enzyme in an inactive form. 
C)  by feedback inhibition. 
D)  a gene coding for the enzyme may be turned off.

Question 14

Energy that is not converted to useful energy is usually given off as

Accepted Answer

A)  radioactivity. 
B)  light. 
C)  electricity. 
D)  heat. 
E)  entropy. 
A)  radioactivity. 
B)  light. 
C)  electricity. 
D)  heat. 
E)  entropy.

Question 15

What is a simple definition of energy, from a biological perspective? Give some examples of how energy is used in a cell.

Accepted Answer

Energy is the ability of a cel

Question 16

The addition of a competitive inhibitor slows down a particular reaction. What could be done to increase the rate of the reaction, even in the presence of the inhibitor?

Accepted Answer

A)  Add more inhibitor. 
B)  Lower the temperature of the reaction. 
C)  Add a coenzyme. 
D)  Add more substrate. 
E)  Allow the reaction to reach equilibrium. 
A)  Add more inhibitor. 
B)  Lower the temperature of the reaction. 
C)  Add a coenzyme. 
D)  Add more substrate. 
E)  Allow the reaction to reach equilibrium.

Question 17

The optimum reaction rate of a particular enzyme occurs at pH 7.3 at 37°C. This reaction would probably proceed faster by

Accepted Answer

A)  increasing the temperature to 38°C and keeping the pH at 7.3. 
B)  increasing the pH and maintaining the temperature at 37°C. 
C)  decreasing the pH and increasing the temperature. 
D)  increasing both temperature and pH. 
A)  increasing the temperature to 38°C and keeping the pH at 7.3. 
B)  increasing the pH and maintaining the temperature at 37°C. 
C)  decreasing the pH and increasing the temperature. 
D)  increasing both temperature and pH.

Question 18

All of the following are examples of noncompetitive inhibitors EXCEPT

Accepted Answer

A)  lead. 
B)  nerve gas. 
C)  arsenic. 
D)  mercury. 
A)  lead. 
B)  nerve gas. 
C)  arsenic. 
D)  mercury.

Question 19

Activation energy can be provided by the kinetic energy of moving molecules.

Accepted Answer

A) True 
 B)False

Question 20

Similar to a car, a human body is about efficient in converting chemical energy to movement.

Accepted Answer

A)  95% 
B)  75% 
C)  25% 
D)  1% 
A)  95% 
B)  75% 
C)  25% 
D)  1%

Exam 6: Energy Flow in the Life of a Cell

The end product of a biosynthetic pathway often acts to block the initial step in that pathway. This phenomenon is called

Which of the following is the best description of a coupled reaction?

ATP is an energy carrier. Where is the energy actually located?

The reactant in an enzyme- catalyzed reaction is the

Enzymes are important because they

During photosynthesis, plants convert light energy to chemical energy. This is an example of

The burning of sugars as fuels for runners is an example of a(n) _ _ chemical reaction, whereas the production of sugars during photosynthesis is an example of a(n) chemical reaction.

Which of the following does NOT have much potential energy?

Why does increasing the temperature of a chemical reaction generally increase the rate of the reaction?

Normally, a certain enzyme has maximum activity at 37°C, but once it has been heated to 100°C and then cooled back down to 37°C, the enzyme is no longer active. Why?

Each of the following requires 12 carbon atoms. Which of the arrangements of carbon atoms has the greatest entropy?

All of the following are ways in which enzymes are regulated by the cell EXCEPT

Energy that is not converted to useful energy is usually given off as

What is a simple definition of energy, from a biological perspective? Give some examples of how energy is used in a cell.

The addition of a competitive inhibitor slows down a particular reaction. What could be done to increase the rate of the reaction, even in the presence of the inhibitor?

The optimum reaction rate of a particular enzyme occurs at pH 7.3 at 37°C. This reaction would probably proceed faster by

All of the following are examples of noncompetitive inhibitors EXCEPT

Activation energy can be provided by the kinetic energy of moving molecules.

Similar to a car, a human body is about efficient in converting chemical energy to movement.

An Introduction to Life on Earth

Atoms, Molecules, and Life

Biological Molecules

Cell Structure and Function

Cell Membrane Structure and Function

Capturing Solar Energy: Photosynthesis

Harvesting Energy: Glycolysis and Cellular Respiration

Cellular Reproduction

Meiosis: the Basis of Sexual Reproduction

Patterns of Inheritance

Dna: the Molecule of Heredity

Gene Expression and Regulation

Biotechnology

Principles of Evolution

How Populations Evolve

The Origin of Species

The History of Life

Systematics: Seeking Order Amid Diversity

The Diversity of Prokaryotes and Viruses

The Diversity of Protists

The Diversity of Plants

The Diversity of Fungi

Animal Diversity I: Invertebrates

Animal Diversity II: Vertebrates

Animal Behavior

Population Growth and Regulation

Community Interactions

Energy Flow and Nutrient Cycling in Ecosystems

Earths Diverse Ecosystems

Conserving Earths Biodiversity

Homeostasis and the Organization of the Animal Body

Circulation

Respiration

Nutrition and Digestion

The Urinary System

Defenses Against Disease

Chemical Control of the Animal Body: the Endocrine System

The Nervous System

The Senses

Action and Support: the Muscles and Skeleton

Animal Reproduction

Animal Development

Plant Anatomy and Nutrient Transport

Plant Reproduction and Development

Plant Responses to the Environment

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