Question 1

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. 
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.

Question 2

Based on the first law of thermodynamics,which of the following statements about a living organism is true?

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) An organism grows by converting energy into organic matter. 
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) An organism grows by converting energy into organic matter.

Question 3

If an enzyme is added to a solution in which its substrate and product are in equilibrium,what will occur?

Accepted Answer

A) Additional product will be formed. 
B) The reaction will change from endergonic to exergonic. 
C) The free energy of the system will change. 
D) Nothing;the reaction will stay at equilibrium. 
A) Additional product will be formed. 
B) The reaction will change from endergonic to exergonic. 
C) The free energy of the system will change. 
D) Nothing;the reaction will stay at equilibrium.

Question 4

The cellular process of breaking down large molecules into smaller ones is defined as

Accepted Answer

A) catalysis. 
B) metabolism. 
C) anabolism. 
D) dehydration. 
E) catabolism. 
A) catalysis. 
B) metabolism. 
C) anabolism. 
D) dehydration. 
E) catabolism.

Question 5

In most exergonic reactions,before products can be formed,the reactants must first overcome a thermodynamic barrier known as the

Accepted Answer

A) entropy of the reaction. 
B) energy conservation of the reaction. 
C) chemical equilibrium of the reaction. 
D) activation energy of the reaction. 
A) entropy of the reaction. 
B) energy conservation of the reaction. 
C) chemical equilibrium of the reaction. 
D) activation energy of the reaction.

Question 6

Which of the following statements is true for all exergonic reactions?

Accepted Answer

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

Question 7

Which of the following is an example of an anabolic pathway?

Accepted Answer

A) a set of reactions that combine monomers into larger,more energy-rich polymers 
B) a set of coupled reactions that are exergonic 
C) a set of reactions that break covalent bonds between molecules to release free energy 
D) a set of reactions that release energy that can be used to drive cellular work 
A) a set of reactions that combine monomers into larger,more energy-rich polymers 
B) a set of coupled reactions that are exergonic 
C) a set of reactions that break covalent bonds between molecules to release free energy 
D) a set of reactions that release energy that can be used to drive cellular work

Question 8

Under a particular set of conditions in the lab,the enzyme in a chemical reaction is saturated.Which of the following alterations to the reaction will increase the rate at which substrate is converted to product?

Accepted Answer

A) increasing the concentration of substrate in the reaction 
B) increasing the amount of enzyme in the reaction 
C) increasing the volume of the reaction without increasing the amount of substrate or enzyme 
D) decreasing the temperature of the reaction 
A) increasing the concentration of substrate in the reaction 
B) increasing the amount of enzyme in the reaction 
C) increasing the volume of the reaction without increasing the amount of substrate or enzyme 
D) decreasing the temperature of the reaction

Question 9

The mechanism by which the end product of a metabolic pathway inhibits an enzyme that catalyzes an earlier step in the pathway is most precisely described as

Accepted Answer

A) competitive inhibition. 
B) cooperativity inhibition. 
C) irreversible inhibition. 
D) feedback inhibition. 
A) competitive inhibition. 
B) cooperativity inhibition. 
C) irreversible inhibition. 
D) feedback inhibition.

Question 10

Which of the following is the most comprehensive definition of metabolism in living organisms?

Accepted Answer

A) Metabolism depends on a constant supply of energy from food. 
B) Metabolism manages the increase of entropy in an organism. 
C) Metabolism refers to the sum of all biochemical pathways involved in synthesis of macromolecules. 
D) Metabolism consists of all the energy transformation reactions in an organism. 
A) Metabolism depends on a constant supply of energy from food. 
B) Metabolism manages the increase of entropy in an organism. 
C) Metabolism refers to the sum of all biochemical pathways involved in synthesis of macromolecules. 
D) Metabolism consists of all the energy transformation reactions in an organism.

Question 11

A mutation that results in a single amino acid substitution in the active site of an enzyme may have which of the following consequences?

Accepted Answer

A) It may alter the ability of a noncompetitive inhibitor to bind to the enzyme. 
B) It may alter the ability of an allosteric regulator to effect enzyme activity. 
C) It may change the substrate specificity of the enzyme. 
D) It may change the ∆G for the original reaction catalyzed by the enzyme. 
A) It may alter the ability of a noncompetitive inhibitor to bind to the enzyme. 
B) It may alter the ability of an allosteric regulator to effect enzyme activity. 
C) It may change the substrate specificity of the enzyme. 
D) It may change the ∆G for the original reaction catalyzed by the enzyme.

Question 12

What is the difference (if any)between the structure of ATP and the structure of the A nucleoside triphosphate used to make RNA?

Accepted Answer

A) The sugar molecule is different. 
B) The nitrogen-containing base is different. 
C) The number of phosphates is three in ATP instead of one in RNA. 
D) There is no difference;they are the same molecule. 
A) The sugar molecule is different. 
B) The nitrogen-containing base is different. 
C) The number of phosphates is three in ATP instead of one in RNA. 
D) There is no difference;they are the same molecule.

Question 13

Most cells cannot harness heat to perform work because

Accepted Answer

A) heat does not involve a transfer of energy. 
B) cells do not have much heat;they are relatively cool. 
C) temperature is usually uniform throughout a cell. 
D) heat can never be used to do work. 
A) heat does not involve a transfer of energy. 
B) cells do not have much heat;they are relatively cool. 
C) temperature is usually uniform throughout a cell. 
D) heat can never be used to do work.

Question 14

Which of the following descriptions would be an example of potential energy?

Accepted Answer

A) the movement of a bicycle coasting down a hill 
B) flood water rushing through a breach in a dam 
C) a spark emitted by explosion of a firework 
D) the chemical bonds in a molecule of sucrose 
A) the movement of a bicycle coasting down a hill 
B) flood water rushing through a breach in a dam 
C) a spark emitted by explosion of a firework 
D) the chemical bonds in a molecule of sucrose

Question 15

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) 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) Energy cannot be transferred or transformed.

Question 16

Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as ________ is to ________.

Accepted Answer

A) exergonic;spontaneous 
B) exergonic;endergonic 
C) free energy;entropy 
D) work;energy 
A) exergonic;spontaneous 
B) exergonic;endergonic 
C) free energy;entropy 
D) work;energy

Question 17

A number of systems for pumping ions across membranes are powered by ATP.Such ATP-powered pumps are often called ATPases,although they don't often hydrolyze ATP unless they are simultaneously transporting ions.Because small increases in calcium ions in the cytosol can trigger a number of different intracellular reactions,cells keep the cytosolic calcium concentration quite low under normal conditions,using ATP-powered calcium pumps.For example,muscle cells transport calcium from the cytosol into the membranous system called the sarcoplasmic reticulum (SR).If a resting muscle cell's cytosol has a free calcium ion concentration of 10-7 while the concentration in the SR is 10-2,then which of the following is the most likely mechanism by which the muscle cell ATPase maintains intracellular calcium concentrations?

Accepted Answer

A) The ATPase pumps calcium from the outside of the cell into the SR against the concentration gradient. 
B) The ATPase pumps calcium from the cytosol into the SR against the concentration gradient. 
C) The ATPase transfers ℗i to calcium ions so that they may diffuse into the SR. 
D) The ATPase opens a calcium ion channel that allows calcium ions to diffuse back into the SR along the concentration gradient. 
A) The ATPase pumps calcium from the outside of the cell into the SR against the concentration gradient. 
B) The ATPase pumps calcium from the cytosol into the SR against the concentration gradient. 
C) The ATPase transfers ℗i to calcium ions so that they may diffuse into the SR. 
D) The ATPase opens a calcium ion channel that allows calcium ions to diffuse back into the SR along the concentration gradient.

Question 18

A series of enzymes catalyze the reactions illustrated in the following metabolic pathway:
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 of A decreases the activity of the enzyme that converts X to Y.What is substance X?

Accepted Answer

A) a coenzyme 
B) an allosteric inhibitor 
C) an intermediate 
D) a substrate 
A) a coenzyme 
B) an allosteric inhibitor 
C) an intermediate 
D) a substrate

Question 19

A series of enzymes catalyze the reactions illustrated in the following metabolic pathway:
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 of A decreases the activity of the enzyme that converts X to Y.The product A functions as which of the following in terms of its effect on the enzyme that converts X to Y?

Accepted Answer

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

Exam 6: An Introduction to Metabolism

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

Based on the first law of thermodynamics,which of the following statements about a living organism is true?

If an enzyme is added to a solution in which its substrate and product are in equilibrium,what will occur?

The cellular process of breaking down large molecules into smaller ones is defined as

In most exergonic reactions,before products can be formed,the reactants must first overcome a thermodynamic barrier known as the

Which of the following statements is true for all exergonic reactions?

Which of the following is an example of an anabolic pathway?

Under a particular set of conditions in the lab,the enzyme in a chemical reaction is saturated.Which of the following alterations to the reaction will increase the rate at which substrate is converted to product?

The mechanism by which the end product of a metabolic pathway inhibits an enzyme that catalyzes an earlier step in the pathway is most precisely described as

Which of the following is the most comprehensive definition of metabolism in living organisms?

A mutation that results in a single amino acid substitution in the active site of an enzyme may have which of the following consequences?

What is the difference (if any)between the structure of ATP and the structure of the A nucleoside triphosphate used to make RNA?

Most cells cannot harness heat to perform work because

Which of the following descriptions would be an example of potential energy?

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

Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as ________ is to ________.

Introduction: Evolution and the Foundations of Biology

The Chemical Context of Life

Carbon and the Molecular Diversity of Life

A Tour of the Cell

Membrane Transport and Cell Signaling

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Development,stem Cells,and Cancer

Viruses

Genomes and Their Evolution

Descent With Modification

Phylogeny

The Evolution of Populations

The Origin of Species

Broad Patterns of Evolution

Early Life and the Diversification of Prokaryotes

The Origin and Diversification of Eukaryotes

The Colonization of Land by Plants and Fungi

The Rise of Animal Diversity

Plant Structure and Growth

Resource Acquisition,nutrition,and Transport in Vascular Plants

Reproduction and Domestication of Flowering Plants

Plant Responses to Internal and External Signals

Homeostasis and Endocrine Signaling

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Reproduction and Development

Neurons,synapses,and Signaling

Nervous and Sensory Systems

Motor Mechanisms and Behavior

Population Ecology and the Distribution of Organisms

Ecological Communities

Ecosystems and Energy

Conservation Biology and Global Change

Filters

Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as is to .