Question 1

ATP is classified as an energy-rich compound because

Accepted Answer

A) it complexes with Mg²+. 
B) it has a relatively low free energy of hydrolysis. 
C) its complete oxidation to carbon dioxide releases a large amount of energy. 
D) of the free energy released from cleavage of the phosphoanhydride bond. 
A) it complexes with Mg²+. 
B) it has a relatively low free energy of hydrolysis. 
C) its complete oxidation to carbon dioxide releases a large amount of energy. 
D) of the free energy released from cleavage of the phosphoanhydride bond. D

Question 2

Enzymes that oxidize NADH can best be measured by the ________ .

Accepted Answer

A) increase in absorbance at 340 nm 
B) decrease in absorbance at 340 nm 
C) increase in absorbance at 250 nm 
D) decrease in absorbance at 250 nm 
A) increase in absorbance at 340 nm 
B) decrease in absorbance at 340 nm 
C) increase in absorbance at 250 nm 
D) decrease in absorbance at 250 nm B

Question 3

Calculate the equilibrium constant for an oxidation-reduction reaction involving the transfer of 1 mole of electrons with ΔE0'= 0.25 V.(R = 8.315 JK-1mol-1,ℱ= 96.48 kJV-1mol-1,T = 298k)

Accepted Answer

A) 1 
B) 6 × 10-⁵ 
C) 1.7 × 10⁴ 
D) 0.49 
A) 1 
B) 6 × 10-⁵ 
C) 1.7 × 10⁴ 
D) 0.49 C

Question 4

ATP can be used to activate a substrate by

Accepted Answer

A) phosphorylation. 
B) adding a nucleotidyl group. 
C) producing inorganic phosphate. 
D) Both A and B. 
A) phosphorylation. 
B) adding a nucleotidyl group. 
C) producing inorganic phosphate. 
D) Both A and B.

Question 5

Studies of specific enzymes in cells may not give information about cell metabolism since

Accepted Answer

A) it is difficult to label many enzymes. 
B) the pathways are too complex. 
C) many enzymes are mutant ones. 
D) conditions in isolation may not be like those inside the cell. 
E) All of the above. 
A) it is difficult to label many enzymes. 
B) the pathways are too complex. 
C) many enzymes are mutant ones. 
D) conditions in isolation may not be like those inside the cell. 
E) All of the above.

Question 6

Calculate △G°'for the reaction shown if the mass action ratio,Q,is 5.3 × 102 M-1 and △G is 46 kJ/mol at a temperature of 298 K.(R = 8.315 J/K-mol)ADP + Pi ⇌ ATP

Accepted Answer

A) 30 kJ/mol 
B) -30 kJ/mol 
C) 61 kJ/mol 
D) -61 kJ/mol 
A) 30 kJ/mol 
B) -30 kJ/mol 
C) 61 kJ/mol 
D) -61 kJ/mol

Question 7

A chemical reaction with a negative enthalpy change and a negative entropy change ________.

Accepted Answer

A) must be spontaneous 
B) must be nonspontaneous 
C) could be either spontaneous or nonspontaneous depending on the temperature 
D) is not possible 
A) must be spontaneous 
B) must be nonspontaneous 
C) could be either spontaneous or nonspontaneous depending on the temperature 
D) is not possible

Question 8

Mutant organisms can be helpful in the study of metabolism because

Accepted Answer

A) one can compare the mutant to a non-mutant organism. 
B) there may be an indication of a natural role for an enzyme. 
C) there may be accumulations of products prior to defective enzymes. 
D) the structures of enzymes may be deduced. 
E) All of the above. 
A) one can compare the mutant to a non-mutant organism. 
B) there may be an indication of a natural role for an enzyme. 
C) there may be accumulations of products prior to defective enzymes. 
D) the structures of enzymes may be deduced. 
E) All of the above.

Question 9

The citric acid cycle is

Accepted Answer

A) anabolic. 
B) catabolic. 
C) both A and B. 
D) linear. 
A) anabolic. 
B) catabolic. 
C) both A and B. 
D) linear.

Question 10

What defines a near-equilibrium reaction?

Accepted Answer

A) Q is close to Keq. 
B) DE0' = 0. 
C) The reaction is a closed system with no flux in or out of the system. 
D) pH is approximately equal to pKeq. 
A) Q is close to Keq. 
B) DE0' = 0. 
C) The reaction is a closed system with no flux in or out of the system. 
D) pH is approximately equal to pKeq.

Question 11

Nucleoside triphosphates exist in a cell as complexes with

Accepted Answer

A) Phosphate ion. 
B) Mg²+ only. 
C) Mg3+ only. 
D) Mg²+ and sometimes Mn²+. 
E) All of the above. 
A) Phosphate ion. 
B) Mg²+ only. 
C) Mg3+ only. 
D) Mg²+ and sometimes Mn²+. 
E) All of the above.

Question 12

Both NADH and NADPH are oxidized in cells,but NADH is more often used in specialized pathways to provide hydride ions for reductive reactions in anabolism.

Accepted Answer

A) True 
 B)False

Question 13

For a step in a reaction pathway to serve as a control point it should be ________.

Accepted Answer

A) irreversible 
B) endergonic 
C) far from equilibrium 
D) Both A and C 
E) All of the above 
A) irreversible 
B) endergonic 
C) far from equilibrium 
D) Both A and C 
E) All of the above

Question 14

g-Glutamyl phosphate is formed as an intermediate in the conversion of glutamate to glutamine by the enzyme glutamine synthetase because

Accepted Answer

A) it has a large negative free energy. 
B) it is positively charged. 
C) it is unstable in water. 
D) it is a nucleophile. 
E) All of the above. 
A) it has a large negative free energy. 
B) it is positively charged. 
C) it is unstable in water. 
D) it is a nucleophile. 
E) All of the above.

Question 15

The free energy for ATP hydrolysis in vivo is actually greater than the standard free energy change of -30 kJ mol-1 because

Accepted Answer

A) it has stronger electrostatic repulsion. 
B) of the actual concentrations of ATP and its hydrolysis products in cells. 
C) it can easily be formed from other nucleotide triphosphates. 
D) it can participate in phosphoryl group transfers. 
E) All of the above. 
A) it has stronger electrostatic repulsion. 
B) of the actual concentrations of ATP and its hydrolysis products in cells. 
C) it can easily be formed from other nucleotide triphosphates. 
D) it can participate in phosphoryl group transfers. 
E) All of the above.

Question 16

ATP is thermodynamically suited as a carrier of phosphoryl groups in animal cells because

Accepted Answer

A) it is stable under cell conditions. 
B) it is not hydrolyzed in cells without enzyme action. 
C) it is intermediate in group-transfer potential. 
D) it can be produced from phosphocreatine. 
E) All of the above. 
A) it is stable under cell conditions. 
B) it is not hydrolyzed in cells without enzyme action. 
C) it is intermediate in group-transfer potential. 
D) it can be produced from phosphocreatine. 
E) All of the above.

Question 17

Which bond in ATP is primarily responsible for its being a high energy molecule?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
A) A 
B) B 
C) C 
D) D

Question 18

A reaction that best serves as a control point for regulation ________.

Accepted Answer

A) is a near equilibrium reaction 
B) has a large positive △G 
C) is metabolically irreversible 
D) follows Michaelis-Menten kinetics 
A) is a near equilibrium reaction 
B) has a large positive △G 
C) is metabolically irreversible 
D) follows Michaelis-Menten kinetics

Question 19

The flow of material through a metabolic pathway is called the ________.

Accepted Answer

A) current 
B) degree of amplification 
C) cascade effect 
D) flux 
A) current 
B) degree of amplification 
C) cascade effect 
D) flux

Question 20

Which thermodynamic quantity is used to determine if a reaction in a cell is spontaneous?

Accepted Answer

A) △G°' 
B) △G 
C) △H 
D) △S 
A) △G°' 
B) △G 
C) △H 
D) △S

Exam 10: Introduction to Metabolism

ATP is classified as an energy-rich compound because

Enzymes that oxidize NADH can best be measured by the ________ .

Calculate the equilibrium constant for an oxidation-reduction reaction involving the transfer of 1 mole of electrons with ΔE0'= 0.25 V.(R = 8.315 JK-1mol-1,ℱ= 96.48 kJV-1mol-1,T = 298k)

ATP can be used to activate a substrate by

Studies of specific enzymes in cells may not give information about cell metabolism since

Calculate △G°'for the reaction shown if the mass action ratio,Q,is 5.3 × 102 M-1 and △G is 46 kJ/mol at a temperature of 298 K.(R = 8.315 J/K-mol)ADP + Pi ⇌ ATP

A chemical reaction with a negative enthalpy change and a negative entropy change ________.

Mutant organisms can be helpful in the study of metabolism because

The citric acid cycle is

What defines a near-equilibrium reaction?

Nucleoside triphosphates exist in a cell as complexes with

Both NADH and NADPH are oxidized in cells,but NADH is more often used in specialized pathways to provide hydride ions for reductive reactions in anabolism.

For a step in a reaction pathway to serve as a control point it should be ________.

g-Glutamyl phosphate is formed as an intermediate in the conversion of glutamate to glutamine by the enzyme glutamine synthetase because

The free energy for ATP hydrolysis in vivo is actually greater than the standard free energy change of -30 kJ mol-1 because

ATP is thermodynamically suited as a carrier of phosphoryl groups in animal cells because

Which bond in ATP is primarily responsible for its being a high energy molecule?

A reaction that best serves as a control point for regulation ________.

The flow of material through a metabolic pathway is called the ________.

Which thermodynamic quantity is used to determine if a reaction in a cell is spontaneous?

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

The Citric Acid Cycle

Electron Transport and Atp Synthesis

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

DNA Replication, repair, and Recombination

Transcription and RNA Processing

Protein Synthesis

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