Question 1

The synthesis of glutamine from glutamate and ammonia is an example of

Accepted Answer

A) transamination. 
B) ATP phosphoryl group transfer. 
C) ADP phosphoryl group transfer. 
D) Inorganic phosphate group transfer. 
A) transamination. 
B) ATP phosphoryl group transfer. 
C) ADP phosphoryl group transfer. 
D) Inorganic phosphate group transfer.

Question 2

Phosphagens are energy-rich phosphoanhydrides found in animal muscle cells and which have higher group-transfer potentials than ATP.

Accepted Answer

A) True 
 B)False

Question 3

Although the CoA thioester is less stable than oxygen esters,it is stable in cells,resisting nonenzymatic hydrolysis at neutral pH values.

Accepted Answer

A) True 
 B)False

Question 4

The phosphoester bond and phosphoanhydride bonds in ATP have the approximately same free energies of hydrolysis.

Accepted Answer

A) True 
 B)False

Question 5

The hydrolysis of ATP to ADP has a △G°'of -30 kJ/mol.If in an E.coli cell the concentrations of ATP,ADP and inorganic phosphate are 7.90 mM,1.04 mM and 7.9 mM,respectively,which statement is true about the hydrolysis of ATP in the cell?(Assumeatemperature of 298 K.R = 8.315 J/K-mol)

Accepted Answer

A) Hydrolysis can proceed spontaneously. 
B) The hydrolysis is at equilibrium. 
C) The formation of ATP from ADP is occurring more rapidly than the hydrolysis. 
D) The hydrolysis is being allosterically controlled. 
A) Hydrolysis can proceed spontaneously. 
B) The hydrolysis is at equilibrium. 
C) The formation of ATP from ADP is occurring more rapidly than the hydrolysis. 
D) The hydrolysis is being allosterically controlled.

Question 6

A given cell type tends to maintain relatively constant internal concentrations of inorganic ions,enzymes and metabolites.

Accepted Answer

A) True 
 B)False

Question 7

Which statement is false about ATP?

Accepted Answer

A) Its concentration in a particular cell usually fluctuates very little. 
B) The concentration of ATP in cells is generally much lower than that of AMP. 
C) Its concentration is maintained in part by adenylate kinase. 
D) The intracellular concentration of ATP varies among cell types. 
A) Its concentration in a particular cell usually fluctuates very little. 
B) The concentration of ATP in cells is generally much lower than that of AMP. 
C) Its concentration is maintained in part by adenylate kinase. 
D) The intracellular concentration of ATP varies among cell types.

Question 8

The formation of acetyl CoA is driven to completion by

Accepted Answer

A) the negative standard free energy for the first step of the reaction. 
B) the negative standard free energy for the final step of the reaction. 
C) removal of the product pyrophosphate by the enzyme pyrophosphatase. 
D) the negative free energy for the formation of an ADP intermediate. 
E) All of the above. 
A) the negative standard free energy for the first step of the reaction. 
B) the negative standard free energy for the final step of the reaction. 
C) removal of the product pyrophosphate by the enzyme pyrophosphatase. 
D) the negative free energy for the formation of an ADP intermediate. 
E) All of the above.

Question 9

In order for a reaction to proceed spontaneously from left to right as written,

Accepted Answer

A) ATP must be involved in the reaction. 
B) a common intermediate must be formed. 
C) the overall free-energy change must be negative. 
D) a phosphate group must be transferred. 
E) All of the above. 
A) ATP must be involved in the reaction. 
B) a common intermediate must be formed. 
C) the overall free-energy change must be negative. 
D) a phosphate group must be transferred. 
E) All of the above.

Question 10

Reactions of most metabolic pathways are in a state of equilibrium and have a △G equal to zero.

Accepted Answer

A) True 
 B)False

Question 11

Phosphorylation of enzymes involved in catabolic pathways usually activates them.

Accepted Answer

A) True 
 B)False

Question 12

Compartmentation of enzymes

Accepted Answer

A) helps prevent loss by diffusion. 
B) keeps separate pools of metabolites in cells. 
C) can help control metabolic pathways. 
D) All of the above. 
A) helps prevent loss by diffusion. 
B) keeps separate pools of metabolites in cells. 
C) can help control metabolic pathways. 
D) All of the above.

Question 13

Consider the synthesis of a biopolymer in which the addition of successive monomers occurs by the same kind of reaction(s).The synthesis of the polymer is a ________ pathway.

Accepted Answer

A) linear 
B) cyclic 
C) spiral 
D) branched 
A) linear 
B) cyclic 
C) spiral 
D) branched

Question 14

Which of the following is not a factor contributing to the large free energy of hydrolysis of ATP?

Accepted Answer

A) Electrostatic repulsion of oxygen atoms. 
B) Better solvation of products than ATP itself. 
C) Complexes with Mg²+ or Mn²+ ions. 
D) Better stability of products than ATP itself. 
E) Electrical shielding of products of hydrolysis. 
A) Electrostatic repulsion of oxygen atoms. 
B) Better solvation of products than ATP itself. 
C) Complexes with Mg²+ or Mn²+ ions. 
D) Better stability of products than ATP itself. 
E) Electrical shielding of products of hydrolysis.

Question 15

All metabolic reactions occur in the cytosol of cells.

Accepted Answer

A) True 
 B)False

Question 16

Most metabolic reactions occur continuously at a fixed rate.

Accepted Answer

A) True 
 B)False

Question 17

ATP has the highest phosphoryl-group-transfer potential in cells.

Accepted Answer

A) True 
 B)False

Question 18

The flow of material through a reaction pathway usually depends on ________.

Accepted Answer

A) control at several steps in the pathway 
B) control of the first step of the pathway 
C) covalent modification of the enzyme that catalyzes the reaction 
D) feed-forward activation 
A) control at several steps in the pathway 
B) control of the first step of the pathway 
C) covalent modification of the enzyme that catalyzes the reaction 
D) feed-forward activation

Question 19

Phosphorylation by protein kinases coordinates regulation of different pathways.Usually this phosphorylation ________ catabolic pathways and ________ anabolic pathways.

Accepted Answer

A) deactivates;deactivates 
B) deactivates;activates 
C) activates;deactivates 
D) activates;activates 
A) deactivates;deactivates 
B) deactivates;activates 
C) activates;deactivates 
D) activates;activates

Question 20

The conversion of glucose-1-phosphate to glucose-6-phosphate by the enzyme phosphoglucomutase has a △G°' of -7.6 kJ/mol.Calculate the equilibrium constant for this reaction at 298 K and a pH of 7.(R = 8.315 J/K-mol)

Accepted Answer

A) 0.003 
B) 0.047 
C) 1.00 
D) 21 
A) 0.003 
B) 0.047 
C) 1.00 
D) 21

Exam 10: Introduction to Metabolism

The synthesis of glutamine from glutamate and ammonia is an example of

Phosphagens are energy-rich phosphoanhydrides found in animal muscle cells and which have higher group-transfer potentials than ATP.

Although the CoA thioester is less stable than oxygen esters,it is stable in cells,resisting nonenzymatic hydrolysis at neutral pH values.

The phosphoester bond and phosphoanhydride bonds in ATP have the approximately same free energies of hydrolysis.

The hydrolysis of ATP to ADP has a △G°'of -30 kJ/mol.If in an E.coli cell the concentrations of ATP,ADP and inorganic phosphate are 7.90 mM,1.04 mM and 7.9 mM,respectively,which statement is true about the hydrolysis of ATP in the cell?(Assumeatemperature of 298 K.R = 8.315 J/K-mol)

A given cell type tends to maintain relatively constant internal concentrations of inorganic ions,enzymes and metabolites.

Which statement is false about ATP?

The formation of acetyl CoA is driven to completion by

In order for a reaction to proceed spontaneously from left to right as written,

Reactions of most metabolic pathways are in a state of equilibrium and have a △G equal to zero.

Phosphorylation of enzymes involved in catabolic pathways usually activates them.

Compartmentation of enzymes

Consider the synthesis of a biopolymer in which the addition of successive monomers occurs by the same kind of reaction(s).The synthesis of the polymer is a ________ pathway.

Which of the following is not a factor contributing to the large free energy of hydrolysis of ATP?

All metabolic reactions occur in the cytosol of cells.

Most metabolic reactions occur continuously at a fixed rate.

ATP has the highest phosphoryl-group-transfer potential in cells.

The flow of material through a reaction pathway usually depends on ________.

Phosphorylation by protein kinases coordinates regulation of different pathways.Usually this phosphorylation ________ catabolic pathways and ________ anabolic pathways.

The conversion of glucose-1-phosphate to glucose-6-phosphate by the enzyme phosphoglucomutase has a △G°' of -7.6 kJ/mol.Calculate the equilibrium constant for this reaction at 298 K and a pH of 7.(R = 8.315 J/K-mol)

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

Filters

Phosphorylation by protein kinases coordinates regulation of different pathways.Usually this phosphorylation catabolic pathways and anabolic pathways.