Question

After reviewing the reactions of glutamine formation on page 90, explain why each of the following statements concerning the third (or overall) reaction is either true or false.

a. If the reaction were written in reverse, its ΔG would be -3.9 kcal/mol.
b. If all reactants and products were at standard conditions at the beginning of an experiment, after a period of time, the [NH₃]/[ADP] ratio would decrease.
c. As the reaction proceeds, the ΔG moves closer to zero.
d. At equiLiBrium, the forward and reverse reactions are equal and the [ATP]/[ADP] ratio becomes one.
e. In the cell, it is possible for glutamine to be formed when the [glutamine]/[glutamic acid] ratio is greater than one.

Answer 1

a. If the reaction were written in reverse, its ΔG would be -3.9 kcal/mol (true). b. If all reactants and products were at standard conditions at the beginning of an experiment, the [NH₃]/[ADP] ratio would decrease (false). c. As the reaction proceeds, the ΔG moves closer to zero (true). d. At equilibrium, the forward and reverse reactions are equal and the [ATP]/[ADP] ratio becomes one (true). e. In the cell, it is possible for glutamine to be formed when the [glutamine]/[glutamic acid] ratio is greater than one (true).

Step-by-step explanation:

a. If the reaction were written in reverse, its ΔG would be -3.9 kcal/mol: This statement is true. The reverse of a reaction has a ΔG that is equal in magnitude but opposite in sign to the forward reaction. Since the forward reaction has a positive ΔG value of 3.9 kcal/mol, the reverse reaction would have a negative ΔG value of -3.9 kcal/mol.

b. If all reactants and products were at standard conditions at the beginning of an experiment, after a period of time, the [NH₃]/[ADP] ratio would decrease: This statement is false. The [NH₃]/[ADP] ratio would actually increase over time, as the reaction proceeds in the forward direction and consumes ADP to produce more NH₃.

c. As the reaction proceeds, the ΔG moves closer to zero: This statement is true. As the reaction proceeds in the forward direction, the ΔG becomes more negative, meaning that the reaction becomes more favorable and spontaneous.

d. At equilibrium, the forward and reverse reactions are equal and the [ATP]/[ADP] ratio becomes one: This statement is true. At equilibrium, the rates of the forward and reverse reactions are equal, and the concentrations of both reactants and products remain constant. This means that the [ATP]/[ADP] ratio would be equal to 1, indicating that the reaction has reached equilibrium.

e. In the cell, it is possible for glutamine to be formed when the [glutamine]/[glutamic acid] ratio is greater than one: This statement is true. The formation of glutamine from glutamic acid is an amino acid synthesis reaction that requires the input of energy. This synthesis can occur when the concentration of glutamine is greater than the concentration of glutamic acid.