Question 1

In order to drive the synthesis of ATP,the hydrolysis of an organic phosphate

Accepted Answer

A)  must have a higher free energy change. 
B)  must have a lower free energy change. 
C)  must have a free energy change equal to that of ATP. 
A)  must have a higher free energy change. 
B)  must have a lower free energy change. 
C)  must have a free energy change equal to that of ATP. A

Question 2

An oxidizing agent

Accepted Answer

A)  loses oxygen. 
B)  gains oxygen. 
C)  loses electrons. 
D)  gains electrons. 
A)  loses oxygen. 
B)  gains oxygen. 
C)  loses electrons. 
D)  gains electrons. D

Question 3

I am performing a reaction,A B,with DG°' = -0.3 kJ/mol.I start the reaction with 10 mM A and no B.After allowing the reaction to proceed for 24 hrs at room temperature and atmospheric pressure,I analyze a sample of the reaction mix to find I now have 1 mM A and 9 mM B.Which of the following conclusions should I make?

Accepted Answer

A) The reaction has reached equilibrium. 
B) I should come back again later; equilibrium has not yet been reached. 
C) The formation of B from A is thermodynamically unfavorable,so I should find another starting material to make B. 
D) I must've screwed up; there's no way I could get that result with that DG°' 
A) The reaction has reached equilibrium. 
B) I should come back again later; equilibrium has not yet been reached. 
C) The formation of B from A is thermodynamically unfavorable,so I should find another starting material to make B. 
D) I must've screwed up; there's no way I could get that result with that DG°' D

Question 4

The number of degrees of freedom a molecule has is related to the numbers of resonant structures it has.

Accepted Answer

A) True 
 B)False

Question 5

Consider these reactions:   What is the DG° of the last reaction?

Accepted Answer

A)  -44 kJ/mol 
B)  -18 kJ/mol 
C)  +18 kJ/mol 
D)  +44 kJ/mol 
E)  Cannot be determined from the information provided. 
A)  -44 kJ/mol 
B)  -18 kJ/mol 
C)  +18 kJ/mol 
D)  +44 kJ/mol 
E)  Cannot be determined from the information provided.

Question 6

An example of an activation step in metabolism is

Accepted Answer

A)  the hydrolysis of a triacylglycerol. 
B)  the cis-trans isomerization of retinal. 
C)  the formation of an acyl derivative of coenzyme A 
D)  the formation of the peptide bond. 
A)  the hydrolysis of a triacylglycerol. 
B)  the cis-trans isomerization of retinal. 
C)  the formation of an acyl derivative of coenzyme A 
D)  the formation of the peptide bond.

Question 7

The production of larger molecules from smaller ones is called

Accepted Answer

A)  metabolism. 
B)  catabolism. 
C)  anabolism. 
D)  none of these 
A)  metabolism. 
B)  catabolism. 
C)  anabolism. 
D)  none of these

Question 8

If the reaction A B has DG = +25 Joule/mol and the reaction B C has DG = -15 Joule/mol,the overall energy change A C will be

Accepted Answer

A)  -40 Joule/mol. 
B)  -15 Joule/mol. 
C)  +10 Joule/mol. 
D)  +40 Joule/mol. 
E)  You cannot determine the overall reaction from the given data. 
A)  -40 Joule/mol. 
B)  -15 Joule/mol. 
C)  +10 Joule/mol. 
D)  +40 Joule/mol. 
E)  You cannot determine the overall reaction from the given data.

Question 9

Exhibit 15A   Consider the reaction of alcohol dehydrogenase.
Refer to Exhibit 15A.Which molecule loses electrons?

Accepted Answer

A)  Ethanol 
B)  NAD+ 
C)  Acetaldehyde 
D)  NADH 
E)  H+ 
A)  Ethanol 
B)  NAD+ 
C)  Acetaldehyde 
D)  NADH 
E)  H+

Question 10

Spontaneous reaction always occurs at a relatively fast rate.

Accepted Answer

A) True 
 B)False

Question 11

When we say that the efficiency of glycolysis is about 33% we mean that

Accepted Answer

A)  2 ATP are produced and 6 ATP are involved in the overall process 
B)  2 ATP are produced in the oxidation of glucose, which contains six carbon atoms 
C)  the energy used to phosphorylate 2 ATP is 33% of the energy released in the process 
D)  all of these 
A)  2 ATP are produced and 6 ATP are involved in the overall process 
B)  2 ATP are produced in the oxidation of glucose, which contains six carbon atoms 
C)  the energy used to phosphorylate 2 ATP is 33% of the energy released in the process 
D)  all of these

Question 12

The conversion of NAD+ to NADH is an example of reduction because

Accepted Answer

A)  the pyridine ring loses electrons (and a hydrogen) 
B)  the pyridine ring gains electrons (and a hydrogen) 
C)  the adenine ring loses electrons 
D)  the adenine ring gains electrons 
A)  the pyridine ring loses electrons (and a hydrogen) 
B)  the pyridine ring gains electrons (and a hydrogen) 
C)  the adenine ring loses electrons 
D)  the adenine ring gains electrons

Question 13

Which of the following is not a mechanism used to activate substrates for further metabolism?

Accepted Answer

A) Addition of a phosphate group. 
B) Combination with a vitamin,such as coenzyme A. 
C) Hydrolyzing a polymer into its component monomers. 
D) Addition of a phosphate group or combining with a vitamin. 
E) All of these processes activate substrates. 
A) Addition of a phosphate group. 
B) Combination with a vitamin,such as coenzyme A. 
C) Hydrolyzing a polymer into its component monomers. 
D) Addition of a phosphate group or combining with a vitamin. 
E) All of these processes activate substrates.

Question 14

In the coenzyme FAD the site to which electrons are transferred is

Accepted Answer

A)  the ribose moiety of the molecule 
B)  a purine ring system 
C)  a pyrimidine ring system 
D)  a nitrogen-containing ring system 
A)  the ribose moiety of the molecule 
B)  a purine ring system 
C)  a pyrimidine ring system 
D)  a nitrogen-containing ring system

Question 15

By definition,a spontaneous reaction is one in which

Accepted Answer

A)  energy is released. 
B)  energy is absorbed. 
C)  the energy change is zero. 
D)  the reaction happens quickly 
E)  energy is released and the reaction happens quickly 
A)  energy is released. 
B)  energy is absorbed. 
C)  the energy change is zero. 
D)  the reaction happens quickly 
E)  energy is released and the reaction happens quickly

Question 16

Biochemists use a modified value for standard DG values because

Accepted Answer

A)  all reagents are not at a 1 molar concentration. 
B)  the pH in living systems is seldom, if ever, near 0. 
C)  the concentration of water is not at 1 molar concentration. 
D)  the reagents are not one molar and the pH = 7. 
E)  All of these justify why biochemists use a special DG value. 
A)  all reagents are not at a 1 molar concentration. 
B)  the pH in living systems is seldom, if ever, near 0. 
C)  the concentration of water is not at 1 molar concentration. 
D)  the reagents are not one molar and the pH = 7. 
E)  All of these justify why biochemists use a special DG value.

Question 17

The body allows energy consuming reactions to occur by coupling them with reactions which have a negative DG.

Accepted Answer

A) True 
 B)False

Question 18

"Oxidation" refers to

Accepted Answer

A)  the loss of oxygen. 
B)  the gain of oxygen. 
C)  the loss of electrons. 
D)  the gain of electrons. 
A)  the loss of oxygen. 
B)  the gain of oxygen. 
C)  the loss of electrons. 
D)  the gain of electrons.

Question 19

In general,the anabolic pathways tend to involve oxidation reactions.

Accepted Answer

A) True 
 B)False

Question 20

Which best describes the DG for hydrolysis of creatine phosphate under cellular conditions in which the concentration of creatine phosphate,creatine,and phosphate all equal 1 mM at 25°C.The DG° for the hydrolysis of creatine phosphate at 25°C is -43 kJ/mol.

Accepted Answer

A)  DG  0 kJ/mol 
A)  DG  0 kJ/mol

Exam 15: The Importance of Energy Changes and Electron Transfer in Metabolism

In order to drive the synthesis of ATP,the hydrolysis of an organic phosphate

An oxidizing agent

The number of degrees of freedom a molecule has is related to the numbers of resonant structures it has.

Consider these reactions: What is the DG° of the last reaction?

An example of an activation step in metabolism is

The production of larger molecules from smaller ones is called

If the reaction A B has DG = +25 Joule/mol and the reaction B C has DG = -15 Joule/mol,the overall energy change A C will be

Exhibit 15A Consider the reaction of alcohol dehydrogenase. Refer to Exhibit 15A.Which molecule loses electrons?

Spontaneous reaction always occurs at a relatively fast rate.

When we say that the efficiency of glycolysis is about 33% we mean that

The conversion of NAD+ to NADH is an example of reduction because

Which of the following is not a mechanism used to activate substrates for further metabolism?

In the coenzyme FAD the site to which electrons are transferred is

By definition,a spontaneous reaction is one in which

Biochemists use a modified value for standard DG values because

The body allows energy consuming reactions to occur by coupling them with reactions which have a negative DG.

"Oxidation" refers to

In general,the anabolic pathways tend to involve oxidation reactions.

Which best describes the DG for hydrolysis of creatine phosphate under cellular conditions in which the concentration of creatine phosphate,creatine,and phosphate all equal 1 mM at 25°C.The DG° for the hydrolysis of creatine phosphate at 25°C is -43 kJ/mol.

Biochemistry and the Organization of Cells

Water: The Solvent for Biochemical Reactions

Amino Acids and Peptides

The Three-Dimensional Structure of Proteins

Protein Purification and Characterization Techniques

The Behavior of Proteins: Enzymes

The Behavior of Proteins: Enzymes, Mechanisms, and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids: How Structure Conveys Information

Biosynthesis of Nucleic Acids: Replication

Transcription of the Genetic Code: Biosynthesis of Rna

Protein Synthesis: Translation of the Genetic Message

Nucleic Acid Biotechnology Techniques

Viruses, Cancer, and Immunology

Carbohydrates

Glycolysis

Storage Mechanisms and Control in Carbohydrate Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Lipid Metabolism

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism: Cellular Signaling

Filters

The conversion of NAD⁺ to NADH is an example of reduction because