Question 1

If the equilibrium constant for the dissociation of lactic acid is 1.38 × 10-4, what is the $\Delta$G°' for this reaction?

Accepted Answer

A)  16.3kJ/mol 
B)  -16.3 kJ/mol 
C)  16.96 kJ/mol 
D)  -16.96 kJ/mol 
E)  27.5 kJ/mol 
A)  16.3kJ/mol 
B)  -16.3 kJ/mol 
C)  16.96 kJ/mol 
D)  -16.96 kJ/mol 
E)  27.5 kJ/mol A

Question 2

Which redox reaction(s) will NOT proceed as written if the initial concentrations of reactants and products are equal? I. pyruvate + NADH $\rightarrow$  lactate + NAD+
II. FADH2 + NAD+ $\rightarrow$  FAD + NADH + H+
III. succinate + NAD+ $\rightarrow$ fumarate + NADH + H+ 
IV. NADH + H+ + ubiquinone $\rightarrow$ NAD+ + ubiquinol
V. cytochrome c-Fe3+ + cytochrome b-Fe2+ $\rightarrow$ cytochrome c-Fe2+ + cytochrome b-Fe3+

Accepted Answer

A)  I and IV 
B)  I, IV, and V 
C)  II 
D)  II and III 
E)  IV and V 
A)  I and IV 
B)  I, IV, and V 
C)  II 
D)  II and III 
E)  IV and V D

Question 3

When a mixture of glucose 6-phosphate and fructose 6-phosphate is incubated with the enzyme phosphohexose isomerase (which catalyzes the interconversion of these two compounds) until equilibrium is reached, the final mixture contains twice as much glucose 6-phosphate as fructose 6-phosphate. Which one of the following statements is best applied to this reaction outlined below? (R = 8.315 J/mol · K; T = 298 K) glucose 6-phosphate $\rightarrow$fructose 6-phosphate

Accepted Answer

A)  $\Delta$G'° is incalculably large and negative. 
B)  $\Delta$G'° is -1.72 kJ/mol. 
C)  $\Delta$G'° is zero. 
D)  $\Delta$G'° is +1.72 kJ/mol. 
E)  $\Delta$G'° is incalculably large and positive. 
A)  $\Delta$G'° is incalculably large and negative. 
B)  $\Delta$G'° is -1.72 kJ/mol. 
C)  $\Delta$G'° is zero. 
D)  $\Delta$G'° is +1.72 kJ/mol. 
E)  $\Delta$G'° is incalculably large and positive. D

Question 4

Which statement is TRUE regarding coupled reactions?

Accepted Answer

A)  The standard free energy changes of the coupled reactions are additive, and their equilibrium constants are multiplicative. 
B)  The coupled reactions must share a common intermediate. 
C)  The free energy of the endergonic reaction must be greater in magnitude than the free energy of the exergonic reaction. 
D)  The standard free energy changes of the coupled reactions are additive, their equilibrium constants are multiplicative, and the coupled reactions must share a common intermediate. 
E)  None of the statements is true. 
A)  The standard free energy changes of the coupled reactions are additive, and their equilibrium constants are multiplicative. 
B)  The coupled reactions must share a common intermediate. 
C)  The free energy of the endergonic reaction must be greater in magnitude than the free energy of the exergonic reaction. 
D)  The standard free energy changes of the coupled reactions are additive, their equilibrium constants are multiplicative, and the coupled reactions must share a common intermediate. 
E)  None of the statements is true.

Question 5

Which statement about NAD+ and NADH is FALSE?

Accepted Answer

A)  NAD+ is oxidized to NADH by $\alpha$-ketoglutarate dehydrogenase. 
B)  Lactate dehydrogenase binds NAD+ tightly in the Rossmann fold. 
C)  NAD+ accepts both electrons as a hydride ion. 
D)  NAD+ is oxidized to NADH by $\alpha$-ketoglutarate dehydrogenase, and lactate dehydrogenase binds NAD+ tightly in the Rossmann fold. 
E)  NAD+ is oxidized to NADH by $\alpha$-ketoglutarate dehydrogenase, and NAD+ accepts both electrons as a hydride ion. 
A)  NAD+ is oxidized to NADH by $\alpha$-ketoglutarate dehydrogenase. 
B)  Lactate dehydrogenase binds NAD+ tightly in the Rossmann fold. 
C)  NAD+ accepts both electrons as a hydride ion. 
D)  NAD+ is oxidized to NADH by $\alpha$-ketoglutarate dehydrogenase, and lactate dehydrogenase binds NAD+ tightly in the Rossmann fold. 
E)  NAD+ is oxidized to NADH by $\alpha$-ketoglutarate dehydrogenase, and NAD+ accepts both electrons as a hydride ion.

Question 6

Which molecule is NOT considered a universal electron carrier?

Accepted Answer

A)  NADH 
B)  ATPF 
C)  ADH2 
D)  FMNH2 
E)  both ATPF and FMNH2 
A)  NADH 
B)  ATPF 
C)  ADH2 
D)  FMNH2 
E)  both ATPF and FMNH2

Question 7

Glycerol 3-phosphate dehydrogenase catalyzes the following reversible reaction:
glycerol 3-phosphate + NAD+ $\rightarrow$ NADH + H+ + dihydroxyacetone phosphate
Given the standard reduction potentials below, calculate $\Delta$G'° for the glycerol 3-phosphate dehydrogenase reaction, proceeding from left to right as shown. Show your work. (The Faraday constant,  , is 96.48 kJ/V · mol.)
dihydroxyacetone phosphate + 2e- + 2H+ $\rightarrow$ glycerol 3-phosphate
E'° = -0.29 V
NAD+ + H+ + 2e- $\rightarrow$ NADH
E'° = -0.32 V

Accepted Answer

To calculate the standard Gibbs free ene

Question 8

Which statement regarding redox reactions is TRUE?

Accepted Answer

A)  NADH and FADH2 are major electron acceptors in the oxidation of fuel molecules. 
B)  In glycolysis, the conversion of 2-phosphpoglycerate to phosphoenolpyruvate is a redox reaction. 
C)  In a redox reaction, the oxidation state of the substrate remains unchanged. 
D)  A redox reaction is spontaneous when the substrate has a greater reduction potential than the product. 
E)  The Nerst equation relates the standard reduction potential of a redox pair to its actual reduction potential at any concentration of either the oxidized or reduced form of the species. 
A)  NADH and FADH2 are major electron acceptors in the oxidation of fuel molecules. 
B)  In glycolysis, the conversion of 2-phosphpoglycerate to phosphoenolpyruvate is a redox reaction. 
C)  In a redox reaction, the oxidation state of the substrate remains unchanged. 
D)  A redox reaction is spontaneous when the substrate has a greater reduction potential than the product. 
E)  The Nerst equation relates the standard reduction potential of a redox pair to its actual reduction potential at any concentration of either the oxidized or reduced form of the species.

Question 9

In general, when ATP hydrolysis is coupled to an energy-requiring reaction, the actual reaction often consists of the transfer of a phosphate group from ATP to another substrate, rather than an actual hydrolysis of the ATP. Explain.

Accepted Answer

When ATP hydrolysis is coupled to an ene

Question 10

Explain why each of the following statements is FALSE.
(a) In a reaction under standard conditions, only the reactants are fixed at 1 M.
(b) When $\Delta$G'° is positive, Keq' > 1.
(c) $\Delta$G and $\Delta$G'° mean the same thing.
(d) When $\Delta$G'° = 1.0 kJ/mol, Keq' = 1.

Accepted Answer

(a) In a reaction under standard conditi

Question 11

Which statement is NOT true regarding the biochemical standard state?

Accepted Answer

A)  The [H+] is 10-7M. 
B)  Temperature is 28°C. 
C)  All reactants and products are present at 1 M concentrations. 
D)  The pressure is 1 atm. 
E)  The concentration of water is essentially constant at 55.5 M. 
A)  The [H+] is 10-7M. 
B)  Temperature is 28°C. 
C)  All reactants and products are present at 1 M concentrations. 
D)  The pressure is 1 atm. 
E)  The concentration of water is essentially constant at 55.5 M.

Question 12

Which compound has the LARGEST negative value for the standard free-energy change ($\Delta$G'°) upon hydrolysis?

Accepted Answer

A)  acetic anhydride 
B)  glucose 6-phosphate 
C)  glutamine 
D)  glycerol 3-phosphate 
E)  lactose 
A)  acetic anhydride 
B)  glucose 6-phosphate 
C)  glutamine 
D)  glycerol 3-phosphate 
E)  lactose

Question 13

The expression $\Delta$G = $\Delta$G'° + RT ln Keq' for the actual free-energy change for the reaction A + B $\rightarrow$ C + D is incorrect. Why is it wrong, and what is the correct expression for the real free-energy change of this reaction?

Accepted Answer

The given expression for the actual free

Question 14

Which is the MOST oxidized carbon atom in a ketohexose sugar?

Accepted Answer

A)  C1 
B)  C2 
C)  C3 
D)  C5 
E)  C6 
A)  C1 
B)  C2 
C)  C3 
D)  C5 
E)  C6

Question 15

Under standard conditions, ATP can be used in phosphate-transfer reactions to generate which molecule?

Accepted Answer

A)  phosphocreatine 
B)  glycerol-3-phosphate 
C)  phosphoenolpyruvate 
D)  1,3-bisphosphoglycerate 
E)  All of the answers are correct. 
A)  phosphocreatine 
B)  glycerol-3-phosphate 
C)  phosphoenolpyruvate 
D)  1,3-bisphosphoglycerate 
E)  All of the answers are correct.

Question 16

During glycolysis, glucose 1-phosphate is converted to fructose 6-phosphate in two successive reactions: glucose 1-phosphate $\rightarrow$  glucose 6-phosphate
$\Delta$G'° = -7.1 kJ/mol
Glucose 6-phosphate $\rightarrow$  fructose 6-phosphate
$\Delta$G'° = +1.7 kJ/mol
$\Delta$G'° for the overall reaction is:

Accepted Answer

A)  -8.8 kJ/mol. 
B)  -7.1 kJ/mol. 
C)  -5.4 kJ/mol. 
D)  +5.4 kJ/mol. 
E)  +8.8 kJ/mol. 
A)  -8.8 kJ/mol. 
B)  -7.1 kJ/mol. 
C)  -5.4 kJ/mol. 
D)  +5.4 kJ/mol. 
E)  +8.8 kJ/mol.

Question 17

What is the CORRECT order of substances in terms of electronegativity, greatest to least?

Accepted Answer

A)  H $\rightarrow$  C $\rightarrow$  N $\rightarrow$ S $\rightarrow$  O 
B)  H $\rightarrow$  C $\rightarrow$ S $\rightarrow$  O $\rightarrow$ N 
C)  O $\rightarrow$  S$\rightarrow$  N $\rightarrow$ C $\rightarrow$  H 
D)  N $\rightarrow$  O $\rightarrow$ S$\rightarrow$ H$\rightarrow$ C 
E)  O $\rightarrow$  N $\rightarrow$  S $\rightarrow$ C $\rightarrow$  O 
A)  H $\rightarrow$  C $\rightarrow$  N $\rightarrow$ S $\rightarrow$  O 
B)  H $\rightarrow$  C $\rightarrow$ S $\rightarrow$  O $\rightarrow$ N 
C)  O $\rightarrow$  S$\rightarrow$  N $\rightarrow$ C $\rightarrow$  H 
D)  N $\rightarrow$  O $\rightarrow$ S$\rightarrow$ H$\rightarrow$ C 
E)  O $\rightarrow$  N $\rightarrow$  S $\rightarrow$ C $\rightarrow$  O

Question 18

Which compound is classified as high energy?

Accepted Answer

A)  phosphoarginine 
B)  succinyl-CoA 
C)  fatty acid-CoA 
D)  All of the answers are correct. 
E)  None of the answers is correct. 
A)  phosphoarginine 
B)  succinyl-CoA 
C)  fatty acid-CoA 
D)  All of the answers are correct. 
E)  None of the answers is correct.

Question 19

Given  $\Delta$ G'° for each of the following reactions,

Accepted Answer

It seems like there is some information

Question 20

Which carbon atom is in the MOST reduced state?

Accepted Answer

A)  a carbon in an alkyl group 
B)  a carbon in an aldehyde group 
C)  a carbon in a ketone group 
D)  a carbon in a carboxylic acid group 
E)  a carbon in an alcohol group 
A)  a carbon in an alkyl group 
B)  a carbon in an aldehyde group 
C)  a carbon in a ketone group 
D)  a carbon in a carboxylic acid group 
E)  a carbon in an alcohol group

Exam 13: Bioenergetics and Biochemical Reaction Types

If the equilibrium constant for the dissociation of lactic acid is 1.38 × 10-4, what is the Δ\DeltaΔ G°' for this reaction?

Which statement is TRUE regarding coupled reactions?

Which statement about NAD+ and NADH is FALSE?

Which molecule is NOT considered a universal electron carrier?

Which statement regarding redox reactions is TRUE?

In general, when ATP hydrolysis is coupled to an energy-requiring reaction, the actual reaction often consists of the transfer of a phosphate group from ATP to another substrate, rather than an actual hydrolysis of the ATP. Explain.

Explain why each of the following statements is FALSE. (a) In a reaction under standard conditions, only the reactants are fixed at 1 M. (b) When Δ\DeltaΔ G'° is positive, Keq' > 1. (c) Δ\DeltaΔ G and Δ\DeltaΔ G'° mean the same thing. (d) When Δ\DeltaΔ G'° = 1.0 kJ/mol, Keq' = 1.

Which statement is NOT true regarding the biochemical standard state?

Which compound has the LARGEST negative value for the standard free-energy change ( Δ\DeltaΔ G'°) upon hydrolysis?

The expression Δ\DeltaΔ G = Δ\DeltaΔ G'° + RT ln Keq' for the actual free-energy change for the reaction A + B →\rightarrow→ C + D is incorrect. Why is it wrong, and what is the correct expression for the real free-energy change of this reaction?

Which is the MOST oxidized carbon atom in a ketohexose sugar?

Under standard conditions, ATP can be used in phosphate-transfer reactions to generate which molecule?

What is the CORRECT order of substances in terms of electronegativity, greatest to least?

Which compound is classified as high energy?

Given Δ\DeltaΔ G'° for each of the following reactions,

Which carbon atom is in the MOST reduced state?

The Foundations of Biochemistry

Water

Amino Acids, Peptides, and Proteins

The Three-Dimensional Structure of Proteins

Protein Function

Enzymes

Carbohydrates and Glycobiology

Nucleotides and Nucleic Acids

DNA-Based Information Technologies

Lipids

Biological Membranes and Transport

Biosignaling

Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway

Principles of Metabolic Regulation

The Citric Acid Cycle

Fatty Acid Catabolism

Amino Acid Oxidation and the Production of Urea

Oxidative Phosphorylation and Photophosphorylation

Carbohydrate Biosynthesis in Plants and Bacteria

Lipid Biosynthesis

Biosynthesis of Amino Acids, Nucleotides, and Related Molecules

Hormonal Regulation and Integration of Mammalian Metabolism

Genes and Chromosomes

DNA Metabolism

RNA Metabolism

Protein Metabolism

Regulation of Gene Expression

Filters

If the equilibrium constant for the dissociation of lactic acid is 1.38 × 10^-⁴, what is the $\Delta$ G°' for this reaction?

Which statement about NAD⁺ and NADH is FALSE?

Explain why each of the following statements is FALSE. (a) In a reaction under standard conditions, only the reactants are fixed at 1 M. (b) When $\Delta$ G'° is positive, K_eq' > 1. (c) $\Delta$ G and $\Delta$ G'° mean the same thing. (d) When $\Delta$ G'° = 1.0 kJ/mol, K_eq' = 1.

Which compound has the LARGEST negative value for the standard free-energy change ( $\Delta$ G'°) upon hydrolysis?

The expression $\Delta$ G = $\Delta$ G'° + RT ln K_eq' for the actual free-energy change for the reaction A + B $\rightarrow$ C + D is incorrect. Why is it wrong, and what is the correct expression for the real free-energy change of this reaction?

Given $\Delta$ G'° for each of the following reactions, $Given \Delta G'° for each of the following reactions,$